The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Greybeard on 23.05. 2018 15:51
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During my recent ride to the BSAOC camp in Cheshire. I thought I could hear a new sound from the engine. I have a tight fitting skidlid and also I was wearing earphone buds to hear my SatNav directions. Anyway, I've been cleaning the bike today. I had not run it since the weekend. When I started it to walk it back into the shed I could deffo hear a new rattle. The sound was mostly on over-run and sounded light, like a small chain. So, I took off the timing cover and adjusted the dynamo chain. Started again; same sound. Took off the sump plate to find this!!
The bits are non-ferrous. Slightly curved bronzy appearance. There was no obvious debris at the bottom of the timing side outer case so I hope they are not from the timing side main bearing. Are they from the camshaft bush? I just know someone here can tell me where they have come from. Obviously, I've now got to take the engine down. I have a new camshaft to put in so here is my chance!
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Something has disintegrated, hopefully a tab washer which may be alloy. Keep us updated please.
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Something has disintegrated, hopefully a tab washer which may be alloy. Keep us updated please.
The bits are yellow, so assuming bronze. It's a bush I guess. I will update as I go.
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Right side bush ? which one gets the oil last ?
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Looks like a drive side main bearing cage has broken up.
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GB,
Sorry to see this. Can't say I've seen anyone post one like this before. It's hard for me to envision a bushing chunking out like this, so I think Black Sheep might be on it. He's probably seen it before. I went looking for something that could support the broken cage idea and came upon the attached picture. Now, we're all in anticipation of the findings.
Richard L.
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well there chunks rather than swarf so sadly not good, first thought was the flange from camshaft bush, intermediate timing sprocket bush - would have to be chunks that fell into the crankcase rather than the timing chest maybe.
Well your going to find out one way or another and the size of them suggest it wont be difficult to spot
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I haven't made a start yet; the dog required a walk and now I'm chillin' so I hope to whip the head and block off tomorrow morning. I'll be completely stripping the bottom end when I can.
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Sorry to hear your news GB. I can't offer technical advice, but if you need some brute force or just an extra pair of hands when dismantling or rebuilding, feel free to PM me.
Paul.
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Sorry to see those pics, especially after an obviously enjoyable weekend. Good luck with it GB and I hope it doesn't prove too stressful or costly for you. No doubt we'll be seeing lots of posts and photos.
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Allow me to redouble Paul's offer, but it might take me a while to swim there.
Richard L.
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BUGGA *ex*. That's the last thing any of us needs to see. I can see Black Sheeps suggestion but it still looks a bit bushy to me.
Before you rip into it, just as a matter of interest. Feel for endfloat or up and down movement on either end of the crank.
Cheers
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My bet it's a camshaft bush *sad2*.
Edit: Been trying to fathom out what diameter it was.
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Thanks fella's, your comments are appreciated. Yes Musky, I'll be checking the health of the crankshaft bearings etc.
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*sad2*
Why do these things always happen at the start of the riding season...
Looks like either a shattered bush shoulder or a disintegrated bearing case. I’m somewhat in the bearing camp. Seen similar chunks in the bottom of a printing press recently when a bearing gave up.
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*sad2*
Seen similar chunks in the bottom of a printing press recently when a bearing gave up.
Never had that with Bremner or Arab platens or Wharfedales *smiley4*
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A collapsed main bearing would be the best for me as I would not need to be fitting and reaming bushes.
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*sad2*
Seen similar chunks in the bottom of a printing press recently when a bearing gave up.
Never had that with Bremner or Arab platens or Wharfedales *smiley4*
They don’t make ‘em like that anymore sir!
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Might that junk be from a piston pin bush? Though I imagine the sound of a blown small-end would be pretty obvious.
Flippin-eck, already on page 2 and I haven't even started yet!
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Don't fret GB. What will be will be (should do a song like that *bash*). We all like a juicy postmortem, just a shame it happens to be a forum member at the start of the riding season.
Just had to delete a thought as to not instill further anguish.
We're all hopeful of a speedy recovery.
Cheers
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What bad luck, let's hope for a speedy recovery for your old girl.
More of the kids inheritence will have to be spent to get her fully fit as it looks like the mains bearing.
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hi guys, GB sorry to see this happen to you it is probably going to be expensive. I was thinking that it could be the cam bush (25) coming loose and bits of it chomped off by the cam lobe with bits being spit over the cam trough. I would have expected to see bits of Ali as well if it was the main bush.
In any case a complete strip down to fix i would think so good luck with the time consuming job, cheers
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Ok, some news. I have the head and block off. The metal is from the timing side little-end bush. The bush has been spinning in the con-rod.
I can also see that the camshaft and followers are buggered. I have a new camshaft that I bought from Andrew Guttman a while ago because the cam I put in the engine when I restored it was an old one that had been reprofiled, so I was expecting trouble. I've just been too busy, (or lazy) to strip the engine to change it!
So far, I know I need a timing side con-rod and cam followers.
The wear on the cam and followers explains the rather rattly engine when it was hot!
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I guess time will take its toll on anything (myself, for example), but gotta wonder if lack of oil up there is a culprit, and why?
Richard L.
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I guess time will take its toll on anything (myself, for example), but gotta wonder if lack of oil up there is a culprit, and why?
Richard L.
I'm pretty good at changing the oil frequently and keep the level up. I'm pretty sure that little-end bush is original. The camshaft was not a surprise.
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I guess time will take its toll on anything (myself, for example), but gotta wonder if lack of oil up there is a culprit, and why?
Richard L.
I'm pretty good at changing the oil frequently and keep the level up. I'm pretty sure that little-end bush is original. The camshaft was not a surprise.
Yep it looks like the hardening has well and truly gone on the cams and followers! You must have been doing the tappet clearances regularly *work*
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I knew all along it was that *whistle*.
*eek* Crikey, I wonder what mine are like?
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Engine is out of the bike and cases are split.
If anyone is interested I took photos of the strip. Some of them are here: https://www.dropbox.com/sh/qfpww7lt8o1bsz1/AADldGcLLg9ANq4k1ETb6Oiya?dl=0
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If I cannot get hold of a replacement small journal conrod, is it feasible to have the old one bored out and a new bush made up to fit?
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G'day GB.
I was just about to suggest that. Any machine shop worth their salt would be able to do that. The rods in my A7 were done 35 years ago and still good. I just can't remember the correct interference fit but I'd say about 1,1/2 thou".
I'd also consider all the other bushes while it's down, especially the cam bushes.
Cheers
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hi greybeard, i have plenty of conrods but you will need new small end bushes. post me your address.
i risk opening a can of worms. but..... i think your cam and followers have ran too hot and starved of oil. i file a thin slot in each follower to allow oil to run down into the trougth. it seems to work.
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hi greybeard, i have plenty of conrods but you will need new small end bushes. post me your address.
i risk opening a can of worms. but..... i think your cam and followers have ran too hot and starved of oil. i file a thin slot in each follower to allow oil to run down into the trougth. it seems to work.
Thanks Edboy, I'll bear that offer in mind.
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hi guys, GB glad you found the problem could have been a lot worst than a small end bush, good luck with the rebuild cheers,
nice pics.
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If I cannot get hold of a replacement small journal conrod, is it feasible to have the old one bored out and a new bush made up to fit?
Its almost standard procedure in NZ! Our bikes tend to have been used a lot during their lives *whistle* (aside from those bikes imported from the US).
A machine shop may also be able to expand a standard bush to suit the rod, and still be able to ream the ID to fit the pin. The expander tool can be a piece of bar with a short raised section of the required diameter. You just push the bush over it using a small press or vice etc.
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Hi GB,
What state is the timing side bush in?
I see you have an iron bodied oil pump so that is good
Check the PRV and make sure its good
The usual cause of cam wear is bad oil pressure
Glad to see its not a major disaster though *smile*
John
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Hi GB,
What state is the timing side bush in?
I see you have an iron bodied oil pump so that is good
Check the PRV and make sure its good
The usual cause of cam wear is bad oil pressure
Glad to see its not a major disaster though *smile*
John
I was knackered at the end of play yesterday so I just had a quick look at bearings. The timing side bush looks good. Before I split the cases I applied leverage to the shaft to see if it visibly lifted in the bush. All that was visible was a slight squeeze of oil. I also tried a pair of internal callipers, (see below) in the empty bush and did not feel any difference in contact as I spun the callipers around.
The PRV is a plunger type that came from SRM so should be good. That pump was described as high capacity and the return flow is very good.
The camshaft I bought had been reprofiled from an old one so was smaller than standard; my tappet adjusters had to be screwed right in to get correct clearances. The seller claimed the shaft had been rehardened, but who knows how good that hardening was? When I last adjusted the tappets I did set them a bit closer than recommended as the engine has always been rattly when hot. It's possible that I left them too tight.
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Check the relief valve plunger and bore for smooth movement and marks which might indicate that they have stuck together at any time.
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I always figure a good press fit is .001 per inch of diameter.
Under an inch is always. 001+ when I make something.
Lee
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I've stripped and cleaned the PRV. It looks good as new.
Timing side bush:
I set my internal callipers to lightly touch inside the timing side bush. As I said yesterday the bush feels consistent all around. I measured the callipers with my brand new 1 to 2" micrometer and found a measurement of 1.3750". The crankshaft journal measures 1.3732". I make the difference 1.8 Thou.
I did not detect any appreciable ovality in the crank journal.
Big end journals, measured North to South and West to East:
Timing side, N/S, 1.4495", W/E, 1.4492"
Drive side, N/S, 1.4498", W/E, 1.4498"
What do you think about all this?
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I always figure a good press fit is .001 per inch of diameter.
Under an inch is always. 001+ when I make something.
Is this referring to getting my Conrod rebushed?
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I've stripped and cleaned the PRV. It looks good as new.
Timing side bush:
I set my internal callipers to lightly touch inside the timing side bush. As I said yesterday the bush feels consistent all around. I measured the callipers with my brand new 1 to 2" micrometer and found a measurement of 1.3750". The crankshaft journal measures 1.3732". I make the difference 1.8 Thou.
I did not detect any appreciable ovality in the crank journal.
Big end journals, measured North to South and West to East:
Timing side, N/S, 1.4495", W/E, 1.4492"
Drive side, N/S, 1.4498", W/E, 1.4498"
What do you think about all this?
You are getting on quickly! Those crank measurements suggest new shells needed, at most to me, the main journal has slightly more clearance than I would like but I think it’s ok, given the engine is going back together as a part worn one anyway, just my opinion!
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Good progress indeed GB. Very pleased to see you've caught things before more major damage. Well done.
Looks like it won't be long before you're riding again at the rate you're going.
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GB,
I meant to ask, were there any signs of gudgeon pins spinning in the pistons? I should add, "...leading to evident wear in the pistons?"
Richard L.
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I meant to ask, were there any signs of gudgeon pins spinning in the pistons?
Hmm, haven't checked for that, yet. I think they are probably OK though as I had to use the hot air gun on the pistons to get the pins out.
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...Those crank measurements suggest new shells needed...
I was planning to get new shells.
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Gudgeon pins are OK.
Big end shells are -10 undersize. Pistons are +20 oversize.
There are a couple of scores along the timing side bore. This seems to explain why that exhaust would smoke after I revved the engine and why there is a lot of carbon in the combustion chamber. I'd like to try and avoid a rebore; how much will honing remove? The scores are not severe but can be felt with a thumbnail.
It certainly looks like the old camshaft and followers have overheated. Either I tightened the tappets too tight, or the hardening failed, or a combination of both :/
Looking at the camshafts I see that the new one I have is a 67-356; the knackered one and the presumably original one I took out when I restored the engine are both 67-334's. What's correct for my engine?
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Hi GB, I hope I'm not the bearer of more bad news for you.
I've checked on the parts lists I have and A7/A10 plunger and s/arm 1954-57 is 67-334. That same number is also listed for A7/A10 s/arm 1958-59.
67-0356 is listed for A Group 1960 - 62.
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Hi GB, I hope I'm not the bearer of more bad news for you.
I've checked on the parts lists I have and A7/A10 plunger and s/arm 1954-57 is 67-334. That same number is also listed for A7/A10 s/arm 1958-59.
67-0356 is listed for A Group 1960 - 62.
Thanks, Roger, I've now found my own parts list and I see that the 67-356 is ok for the year of my machine but is for the Star Twin and Shooting Star. What difference would this make to my low comp engine?
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Not a lot. The 356 will be absolutely fine.
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Thanks, Roger, I've now found my own parts list and I see that the 67-356 is ok for the year of my machine but is for the Star Twin and Shooting Star. What difference would this make to my low comp engine?
Yes, 67-356 also for the 1954-57 Star Twin and Shooting Star, however I'm not that technical savvy to be able to advise but I'm sure someone here will be able to.
Edit: There you go *smile*.
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Not a lot. The 356 will be absolutely fine.
Are the lobes slightly higher, causing the valves to open wider?
Or are the lobes a slightly different profile to affect the timing of the opening and closing of the valves?
Or a combination of both?
Edit: If they lift the tappets and pushrods higher would valve spring strength and valve clearance be something to consider?
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Not a lot. The 356 will be absolutely fine.
Are the lobes slightly higher, causing the valves to open wider?
Or are the lobes a slightly different profile to affect the timing of the opening and closing of the valves?
Or a combination of both?
Edit: If they lift the tappets and pushrods higher would valve spring strength and valve clearance be something to consider?
I await more input from the Southern Hemisphere...
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G'day GB.
A 356 will be fine in your motor and give a fair increase in performance (a couple extra ponies). No problem with springs and clearances. Looks like the new one has been nitrided *wink2*.
Cheers
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Thanks, Musky. How about the tramlines in one bore? Can I just get it honed?
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Yes I don't think it's bad enough to warrant a rebore. Try to keep the piston/bore clearance to 5 thou", they will run with more but sound sloppy. New set of rings and away you go.
Cheers
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Hi GB,
The lines in the bores are the result of shrapnel from the cam and followers
If otherwise unworn I would opt for a hone and a set of quality rings, you might find scores on the rings????
The 356 cam will be an improvement and should run quieter later figures for valve clearances apply
Next question is the quality of replacement followers *????*
I have not had problems with SRM's stellite faced ones, I have fitted them to all the A engines I have rebuilt
Good oil return is no indication of how well *doh*the pressure side is doing *doh*
John
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Thanks guys!
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It certainly looks like the old camshaft and followers have overheated. Either I tightened the tappets too tight, or the hardening failed, or a combination of both :/
Looking at the camshafts I see that the new one I have is a 67-356; the knackered one and the presumably original one I took out when I restored the engine are both 67-334's. What's correct for my engine?
I’ve a (srm) 356 cam in my ‘56 and it’s a straight swap with the 334, it’s generally accepted there is no downside to the upgrade to a 356 from a 334. The 356 was fitted to late GFs and early rockets. The later 357 cam as fitted to rockets can hit the crankcase of a GF due to its higher lift, but even this is easily fixed with a grinder *work*
I don’t think you easily could buy a new 334 anyway. I’ve a box of used ones I doubt anyone would want!
My guess is your old 334 cam was ground to return it to shape and was not re-hardened afterwards, and the grinding went through the hardening layer, leading to the excessive wear you can see on the cam, it’s possible the followers had the same fault.
There is risk with re grinding A10 cams and followers that afterwards the tappets are not able to touch the cam base circle, there is not much extra movement in the followers before they hit the “stop” in the barrel.
It’s got to be worth a try hone and new rings (at most) isn’t it? I fitted new pistons on a used rehoned bore and 005 plus a bit clearance and it runs great, no smoke or rattles 7500 Miles later.
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I can't add anything that I can think of that hasn't been said, except o say that I'm running a re-ground 67-357 in my early BA10 and it goes fine and doesn't clash in the oil-bath, although some of the points raised above have niggled in my mind as they came to my attention after I'd rebuilt it ie;
There is risk with re grinding A10 cams and followers that afterwards the tappets are not able to touch the cam base circle, there is not much extra movement in the followers before they hit the “stop” in the barrel.
One thing I'll ask GB is if you can measure the length of your pushrods, if it's no trouble ?
Hoping it all goes well- don't stress though, (your) Summer hasn't even started yet so you'll still have plenty of daylight to do it.. *smile*
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dutch, I'll get back to you later on that. They are £SRM push-rods.
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Good news and no doubt a relief for GB that there is consensus that he can safely use his later camshaft and with some benefit *smile*.
Just as a matter of interest . . . and before things move on can anybody briefly say what the difference is between the earlier and later camshafts (apart from the pt no), i.e. completely different shape to profiles or just higher peaks to the lobes, etc?
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Wow GB you ripped into sorting this well done
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G'day Roger
Inlet opens before tdc closes after bdc. Exhaust opens before bdc closes after tdc.
334 inlet has 280 degrees duration, exhaust 270 degrees, 55 degrees overlap (both valves open)
356 " " 284 " " " 284 " 79 " "
357 " " 299 " " " 295 " 88 " "
358 I don't have figures and I don't have lift figures at hand. I think Rocket Racer may have that info.
Cheers
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Thanks for that Musky *respect*, I was just curious what the difference was. So to my un-technical details understanding - the valves are open to both inlet and exhaust for slightly longer?
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So, better breathing then?
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Take a look here for the various cam profiles versus valve opening:
http://atlanticgreen.com/bsamain.htm
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So, better breathing then?
I always understood that the speed of the burnt gases leaving the cylinder helps sucking in the fresh mixture, hence the overlap. This would mean though that the overall fuel consumption will rise if there’s more overlap.
I also wonder if the carb would need to be jetted differently?
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I don't know if I should create a fresh thread, but. I'm cleaning bits-n-bobs. I've removed the spring loaded check valve in the timing side case. I missed that when I restored the engine six years ago. The bits all looked good but I'm going to order a new ball and spring. I understand that I should lightly tap the ball into its seat to make sure the seal is as good as possible.
I was wondering if I should pull the oil suction pipe out to clean the galleries more thoroughly. Is the top end locked into the case with a glue?
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I also wonder if the carb would need to be jetted differently?
I must admit that did cross my mind also, Monobloc 276 vs 389 *dunno*.
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Sludge! I'm not sure how many miles I've done * in the last six years since I cleaned the sludge trap but this is what came out today. Probably not a problem but it goes to show that even with an external filter and monograde oil the sludge trap is still doing a good job.
* An indication of my mileage is given by how long you expect Avon SM and Speedmaster tyres to last because they are getting a bit low on tread!
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I always understood that the speed of the burnt gases leaving the cylinder helps sucking in the fresh mixture, hence the overlap. This would mean though that the overall fuel consumption will rise if there’s more overlap.
I also wonder if the carb would need to be jetted differently?
There’s more to long duration cams than the overlap (period when both valves are open, although yes, the inertia of the departing exhaust charge reduces pressure in the combustion chamber and starts to draw the fresh charge in. Overlap also allows some of the more complicated sonic effects of a tuned exhaust.
Early opening of the inlet valve before TDC means it’s already open by a useful amount when the piston starts to descend. Late closing of the inlet valve after BDC allows the inertia of the incoming charge to cause cylinder filling to continue after the compression stroke has started. This effect needs a few 1000s of rpm to work: at idle and low rpm, late closing of the inlet has the ill-effect of allowing mixture to be pushed back out through the inlet ports and carburettor. Mixture being blown out through the carb and then sucked back in causes richness that fouls plugs in traffic jams.
Early opening of the exhaust valve before BDC on the power stroke lets the gases start to be expelled by their own expansion pressure, at a time when they won’t do much more useful work pushing the piston down.
Are we back where we started?
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There’s more to long duration cams than the overlap (period when both valves are open, although yes, the inertia of the departing exhaust charge reduces pressure in the combustion chamber and starts to draw the fresh charge in. Overlap also allows some of the more complicated sonic effects of a tuned exhaust.
Early opening of the inlet valve before TDC means it’s already open by a useful amount when the piston starts to descend. Late closing of the inlet valve after BDC allows the inertia of the incoming charge to cause cylinder filling to continue after the compression stroke has started. This effect needs a few 1000s of rpm to work: at idle and low rpm, late closing of the inlet has the ill-effect of allowing mixture to be pushed back out through the inlet ports and carburettor. Mixture being blown out through the carb and then sucked back in causes richness that fouls plugs in traffic jams.
Early opening of the exhaust valve before BDC on the power stroke lets the gases start to be expelled by their own expansion pressure, at a time when they won’t do much more useful work pushing the piston down.
Are we back where we started?
Are you talking about more extreme cams than my 67-356?
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I was wondering if I should pull the oil suction pipe out to clean the galleries more thoroughly. Is the top end locked into the case with a glue?
When I bought SRMs magnetic sump filter the instructions said put a ring spanner over the scavenge pipe to move it forwards or backwards to align it with the hole in the filter. Mine moved easily and was obviously swivelling, so I would assume it's a press fit. The instructions to move it left or right was to tap it with a hammer. I'm not sure if that bent the pipe sideways to align it or moved it in and out of the hole. All I can say is that it was easy and worked fine. Others may be able to give you more precise explanation.
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I've been online and ordered piston rings, big end shells, cam followers, gaskets and seals.
I still need sludge trap plugs and oil check valve spring and ball and clutch centre tab washer.
Today, after emptying and filling the dishwasher and reassembling brother-in-laws mower motor I have been mostly scraping old gasket off and decoking the combustion chambers. I will strip, decoke and regrind the valves when I get my new spring compressor. When I have all the new parts I will be carefully washing parts in something suitable, blow drying and wrapping in plastic bags ready for a surgically clean rebuild.
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Jeez GB, they say that women are good in multitasking but you are the living proof of the contrary... ;) *smile*
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Putting my rebuild to shame *yeah*
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Dynamo belt kit ordered from Dynamo Regulators.
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G'day GB.
The joys of retirement hay. You can be as quick or slow as you like.
Cheers
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I don't know if I should create a fresh thread, but. I'm cleaning bits-n-bobs. I've removed the spring loaded check valve in the timing side case. I missed that when I restored the engine six years ago. The bits all looked good but I'm going to order a new ball and spring. I understand that I should lightly tap the ball into its seat to make sure the seal is as good as possible.
I was wondering if I should pull the oil suction pipe out to clean the galleries more thoroughly. Is the top end locked into the case with a glue?
In my limited experience the suction pipe is glued in. If it’s heated it should come loose as the glue softens. I used loctite bearing retainer to glue mine back in. An easy job.
Yes I’d lightly tap the ball, but I don’t think that will do much it’s difficult to see how the seat could wear and then not seal!
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RichardL uses a different method. Glues a ball to a stick and laps the seat with paste. If doing it that way I'd only use Brasso and clean thoroughly after.
I buy two balls *whistle* and use one to tap (just a very light tap) the seat and throw it away (or keep for next time) and use the other.
Cheers
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Are you talking about more extreme cams than my 67-356?
If you only hear good reports about the 356, then you’ll probably be happy with it too. Its having been original equipment on the Super Rocket (if I’ve got that right) is a good sign too.
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it’s difficult to see how the seat could wear and then not seal!
The ball and spring are in a larger bore hole so the ball has to find it's own seat. Over time the spring weakens, the ball isn't hitting the seat square on and can wear off center. Mine lasted about 30 years (good for the first 29) but leaks like a sieve now.
Cheers
ps: add to that all the fine debris (all that stuff in the sludge trap) being pumped through it.
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Jeez GB, they say that women are good in multitasking but you are the living proof of the contrary... ;) *smile*
I also do most of the cooking at home! *good3*
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RichardL uses a different method. Glues a ball to a stick and laps the seat with paste.
Muskrat,
Thanks for the recognition. My bike has stayed amazingly free of wet sumping since doing this, more than two years ago now. Can't lose sight of the fact that I put in an SRM pump at the same time. Before that work, sitting more than a week, or so, meant draining the sump. Now, months can go by and wet sumping is minimal (not saying zero), with no sump draining required. Also can't say that I didn't just get lucky or that things won't change tomorrow, but, for now, I'm happy with it.
Richard L.
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Mine is also pretty good. After months of not running, I checked that there was oil covering the tank filter, started the engine, fast idle, pumped the oil back into the tank.
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Jeez GB, they say that women are good in multitasking but you are the living proof of the contrary... ;) *smile*
I also do most of the cooking at home! *good3*
I do ALL of the cooking at home . *sick* *sad2*
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Jeez GB, they say that women are good in multitasking but you are the living proof of the contrary... ;) *smile*
I also do most of the cooking at home! *good3*
I do ALL of the cooking at home . *sick* *sad2*
I'm rubbish at it. When my wife was out I made a cup of coffee with Bisto once *red*. After drinking half of it I said to my wife 'I don't go much on the new coffee'. Looking surprised she said 'What new coffee?'. When I pointed to it she said 'That's Bisto you fool' *eek*.
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I've opened a new Bisto & gravy post in Off-topic
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Checking the pistons in the bores. Rings are off. I used a block to keep the piston in the normal running area. I can get a 2 thou feeler between the piston skirt and the bore but cannot get a 3 thou feeler in. My thoughts on this are that if I can get the marked bore honed by say half a thou I may still be ok. Do you agree?
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depends on how much they take out, but I would say yes, ive seen somewhere that even at 5 or 6 thou you don't get piston slap, but I do know I once used old genuine bsa pistons and got the barrels bored to suit then years later let an engineer talk me into having the bores honed to get the lip out above the rings and one pot developed slap, but I ran it for a couple of summers ticking away and annoying me, when I stripped it the piston was visibly hammered and there was about 8 thou so it depends on your score depth
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depends on how much they take out, but I would say yes, ive seen somewhere that even at 5 or 6 thou you don't get piston slap...
...so it depends on your score depth
Musky advised that I should not have more than 3 thou so your thoughts on having maybe 5 or 6 thou are encouraging. Obviously I will be asking them to take the minimum out.
What about using a mechanics glaze buster; would using one of those be a bad idea or would it take out these shallow tramlines?
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I don’t think you’re getting a proper measurement.
A 2.75” bore with less than 3 thou clearance would probably have seized.
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I don’t think you’re getting a proper measurement.
A 2.75” bore with less than 3 thou clearance would probably have seized.
Scrolling back, I see you have what look like split skirt pistons, so your close clearance may be correct. I thought pistons like that were ancient history by now.
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ive just found the book and super rocket is 5 thou shooting star 3 but when I rebuilt mine after the oil disaster 2 years ago I honed the barrels I fitted with a do it yourself honer and got a very tight 5 and nice 4 thou and its ok. I would let the honer have the pistons and tell them not to take more than 4 even if it leaves a shadow, like triton thrasher says you've got split skirts that work at finer tolerance. bit off topic but a mate rebuilt his triton [morgo barrels 750] after I told him to get rid of the lip at the bottom of his barrels and he broke the oil rings *eek*
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I don’t think you’re getting a proper measurement.
A 2.75” bore with less than 3 thou clearance would probably have seized.
Scrolling back, I see you have what look like split skirt pistons, so your close clearance may be correct. I thought pistons like that were ancient history by now.
I'm pretty sure that the bike came to me in 1973 with these +20 pistons so not surprised they are old-school. I put new rings on 6 years ago and will do again this time
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G'day GB.
That'll be fine mate. 3-5 is OK for a road motor, I ran 8 in the racer. Just make sure the ring gaps are good.
Cheers
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Checking ring gaps is a good idea, especially in a case like this where the bore may be slightly smallish, for that close bore clearance.
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Checking ring gaps is a good idea, especially in a case like this where the bore may be slightly smallish, for that close bore clearance.
Don't fret, it's on the to-do list *smile*
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I was wondering if I should pull the oil suction pipe out to clean the galleries more thoroughly. Is the top end locked into the case with a glue?
I've removed the pick-up pipe using some heat, (I was a bit concerned about warming the case near the timing side bush!). I now cannot see any point in removing the pipe as it just connects through the case with no side ports. It can be cleaned just as well in situ.
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I took the barrels to a rebore shop. They've taken the piston clearance to 5 thou and the tramlines are still evident. I'm going to collect the block and try it. If that side is still smoky I'll consider a rebore. I've asked them to deglaze the other bore while it's there. Cost for the work is £31.
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I was wondering if I should pull the oil suction pipe out to clean the galleries more thoroughly. Is the top end locked into the case with a glue?
I've removed the pick-up pipe using some heat, (I was a bit concerned about warming the case near the timing side bush!). I now cannot see any point in removing the pipe as it just connects through the case with no side ports. It can be cleaned just as well in situ.
I agree. My pick up pipe was only removed so the sump gasket area could be milled flat. There was a step on my cases as they were “mismatched” cases.
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I've collected my barrel from the machine shop in Coventry. They took another skim and have now removed the tramlines. Looks good. I'll check skirt clearance when I've cleaned the barrels. Great chaps to deal with. I'll give them a mention in the Services section of the forum.
Bits have started to arrive. This picture shows SRM's contribution. These items cost £20.39, (including tax and carriage)!!
Sludge trap plugs and oil check valve spring.
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Whoopy!
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i have not been to the pub,[that's tmow *countdown* *bash*] me and our kid had to freeze the bloody water pipe because stop cock knackered , good job he had freezer kits, anyway to the point, you carn't beat new toys coming through the post for your rebuilds , when you open up your packages it smells like victory, greybeard I think you would have got away with a shadow of the scores left I hope they've not taken too much like my engineer did and left me with the annoying piston slap
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you carn't beat new toys coming through the post for your rebuilds , when you open up your packages it smells like victory, greybeard I think you would have got away with a shadow of the scores
Yes, I must say I'm enjoying all these parcels arriving; just like Christmas!
left I hope they've not taken too much like my engineer did and left me with the annoying piston slap
I haven't checked it yet. The engineer said he got the lines out with 5 thou skirt clearance.
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A box of bits arrived from Fecked.
I think it's pretty cheap of the current owners of the Hepolite name to print the box dirty, as though it's NOS!
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Just love those Hepolite packets and boxes, they look like they've been kicking around on a shelf for the last 50-60 years
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Just love those Hepolite packets and boxes, they look like they've been kicking around on a shelf for the last 50-60 years
Sarcasm?
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Without taking the dratted cost into consideration *pull hair out* I bet you're looking forward to rebuilding now *smile*.
I'm certainly looking forward to following your progress.
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Sarcasm?
not intended GB, I think the number of the Hepolite boxes that come out, they can't be original anymore, so somebody has their eye the value of nostalgia (full marks to them), now your going to tell me they have been sitting on a shelf for decades ;)
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The modern Heoplite boxes have grease marks printed on them. This is surely to try to con the buyer into believing they are new old stock.
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Without taking the dratted cost into consideration *pull hair out* I bet you're looking forward to rebuilding now *smile*.
I'm certainly looking forward to following your progress.
I'm touched, (we know that GB!) that you care Roger! I'm still planning to get to Norfolk BSAOC camp, weekend after next. I'm still waiting for some more parts but I intend to get on with stuff tomorrow and probably as much time next week as 'She' will tolerate.
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The modern Heoplite boxes have grease marks printed on them. This is surely to try to con the buyer into believing they are new old stock.
I’m sure they don’t expect to fool anyone.
It’s just a bit of retro chic.
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Got a chance to go out to the shed this morning. The barrel that was scored has cleaned up with a 5 thou skirt clearance. I am happy about that.
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Valve spring compressor via eBay has arrived. Even more parts arrived today.
I've had this expanding reamer in my odds-n-sods box for ages. I've cleaned it up this morning. It appears to be suitably sized for the A10 small-end bush. This means that I've probably had the tool since I rebuilt my Ariel Huntmaster waaay back in 1966. What do you say about using this reamer on my bike? The blades may not be extremely sharp anymore as they've been in a box of other tools. I'm worried about getting judder in the cut. Should I be looking for a fixed size reamer?
I found this thread:
https://www.a7a10.net/forum/index.php?topic=10506.msg78055#msg78055
I should be able to use my pillar drill as a rigid table and reamer holder to get the cut accurately at right-angles. (I'm not planning to use the drill motor!)
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I've got a set of them in a wooden box GB, have used them for stuff other than engine or fast moving bits, I now what you mean by judder, but my concern is/was I could not work out in my head if they reamed parallel or slight taper, has to be parallel of course but you know if you sow a seed of doubt it grows, I satisfied myself by reaming from each side - ah what happened to the unbound confidence of youth
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I'd entrust reaming an urgently needed small end bush to a competent machine shop, but that's based on my experience of judder with an adjustable reamer. You might easily be better at it than me, which would not be difficult.
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I went to the pub at 2-30pm and fell through the door at 1am [*** ed]I am ill! yes in the head.. I like your new toys greybeard ive been using same spring compresser for many years on cars and bikes , a very good tool to have , I once lent it out and forgot who had it, I got it back about a year later after knocking on many doors to find it
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Read somewhere a while ago that Hepolite has been taken over by Wassell and the pistons they supply are JCC pistons made in Taiwan can anyone confirm this.
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...I went to the pub at 2-30pm and fell through the door at 1am [*** ed]I am ill! yes in the head......
You did ok then- considering *eek*
« Reply #70 on: May 27, 2018, 02:45:16 »
Quote
Quote from: Morris
I always understood that the speed of the burnt gases leaving the cylinder helps sucking in the fresh mixture, hence the overlap. This would mean though that the overall fuel consumption will rise if there’s more overlap.
I also wonder if the carb would need to be jetted differently?
There’s more to long duration cams than the overlap (period when both valves are open, although yes, the inertia of the departing exhaust charge reduces pressure in the combustion chamber and starts to draw the fresh charge in. Overlap also allows some of the more complicated sonic effects of a tuned exhaust.
Early opening of the inlet valve before TDC means it’s already open by a useful amount when the piston starts to descend. Late closing of the inlet valve after BDC allows the inertia of the incoming charge to cause cylinder filling to continue after the compression stroke has started. This effect needs a few 1000s of rpm to work: at idle and low rpm, late closing of the inlet has the ill-effect of allowing mixture to be pushed back out through the inlet ports and carburettor. Mixture being blown out through the carb and then sucked back in causes richness that fouls plugs in traffic jams.
Early opening of the exhaust valve before BDC on the power stroke lets the gases start to be expelled by their own expansion pressure, at a time when they won’t do much more useful work pushing the piston down.
Are we back where we started?
That could explain why mine is a bit fumey around town and may explain higher consumption ratio....
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Read somewhere a while ago that Hepolite has been taken over by Wassell and the pistons they supply are JCC pistons made in Taiwan can anyone confirm this.
Hepolite is just a brand. Their Bradford factory has been closed for a long time.
Wassell owns the Hepolite brand and they stick it on boxes containing Taiwanese JCC pistons. They are good pistons and may be better than original British Hepolite.
I don’t know what rings Wassell sell as Hepolite. Their circlips looked dreadful to me and I bought alternative ones from EBay.
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Today's work:
Pic 1: Timing side case with new ball and spring fitted to anti wet-sump arrangement. Oil pickup pipe resealed.
Pic 2: Head, (and barrel) masked-up prior to spraying with heatproof paint. Items then baked in the oven, (which made someone rather cross!)
Pic 3: New style sludge trap plug fitted
Pic 4: Valve grinding
Pic 5: Combustion chambers holding petrol
Pic 6: Oil tank, pipes and filter next off for cleaning
I am now in need of a useable conrod. Monday, I'm going to take my worn one to my new friends at Coventry Boring and Metalling and ask them to machine the rod, make a new bush and ream it to fit the Gudgeon Pin for me. I cannot get an oversize bush delivered quickly so I'm hoping that the engineers will be able to modify a stock bush from another source.
PS: I also fitted new seals in the drive side bearing and clutch.
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Read somewhere a while ago that Hepolite has been taken over by Wassell and the pistons they supply are JCC pistons made in Taiwan can anyone confirm this.
Hepolite is just a brand. Their Bradford factory has been closed for a long time.
Wassell owns the Hepolite brand and they stick it on boxes containing Taiwanese JCC pistons. They are good pistons and may be better than original British Hepolite.
I don’t know what rings Wassell sell as Hepolite. Their circlips looked dreadful to me and I bought alternative ones from EBay.
Well, I hope they source decent quality rings as well. I'm not a tearaway these days so anything I put in this engine should be low-stressed.
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I have put Hepolite pistons and rings in the SA. They came in the famous box with the fingerprints and all. Clocked up about 300 miles now and they behaved flawlessly.
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GB,
If you were going to attempt to use that reamer for the little ends:
A trick I learned a long time ago to help cut down on chatter while using an adjustable reamer:
Pack the blades full of axle grease, then wrap the whole mess one time around in wax paper.
The grease dampens out the harmonics, and the wax paper helps keep chips out of the grease just in case you have to adjust and hit it again.
Lee
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Lee, thanks for that tip. Are you saying you ream with the paper on?
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I have put Hepolite pistons and rings in the SA. They came in the famous box with the fingerprints and all. Clocked up about 300 miles now and they behaved flawlessly.
300 whole miles?
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Lee, thanks for that tip. Are you saying you ream with the paper on?
Yup, leave the wax paper on.
The guy who showed me this was a known trickster, so I automatically thought he was full of B.S.
There is no doubt its messy, but also no doubt it helps the surface finish too.
Lee
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I have put Hepolite pistons and rings in the SA. They came in the famous box with the fingerprints and all. Clocked up about 300 miles now and they behaved flawlessly.
300 whole miles?
Ain't bad in 2 weeks time I guess ;)
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300 whole miles?
At least his bike runs.
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300 whole miles?
At least his bike runs.
Ouch!
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Hi GB and All,
If and when using an adjustable reamer, take very small cuts, if the blades are dull it wont take fine cuts so you adjust some more and some more until they dig in and produce a series of ridges *problem* *warn*
A spiral fixed size reamer is a better bet, best of all is a Sunnen hone and an experienced operator
A "normal pillar drill" would not be accurate (square) enough to ensure alignment
John
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Hi GB and All,
If and when using an adjustable reamer, take very small cuts, if the blades are dull it wont take fine cuts so you adjust some more and some more until they dig in and produce a series of ridges *problem* *warn*
A spiral fixed size reamer is a better bet, best of all is a Sunnen hone and an experienced operator
A "normal pillar drill" would not be accurate (square) enough to ensure alignment
John
Valuable information. Thanks.
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Cleaned the bores and checked ring gaps today. All rings have a 10 thou gap out of the box.
I also fitted new cam followers to the block.
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Moving right along. She'll be back on the road in no time at this rate!
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Been in the shed most of today. I have the short engine back in the frame. I've fitted the dynamo belt kit. I have the clutch and primary on. I've taken advice from 'Er Indoors' and stopped before I start making mistakes.
I'm glad someone here pointed out the issue of modern oil pump gaskets having holes that are smaller than the pump ports. The holes in this gasket were only 3/16"! I opened these up with a hot skewer.
Tomorrow I expect to get the engine running.
I'm now hoping that I can get to the BSAOC Norfolk camp at the weekend. It's a long run, so will give the engine a good start to its bedding in.
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G'day GB.
My next rebuild will be a lot quicker if I post it over to you! *smile*
Cheers
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G'day GB.
My next rebuild will be a lot quicker if I post it over to you! *smile*
Cheers
Please do; you may not get it back though!
Waiting for parts to arrive has been the only real delay.
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Pistons and block fitted. Mag timed. The head is on. I've stopped for lunch. I'm bracing myself for 'The Pushrod Experience' *work*
PS. Edboy very kindly sent me a pair of conrods from his stock. However, as I doubted my ability to achieve a good result with my 52 year old adjustable reamer, and, as I'd found a friendly, fairly local engineering shop, that obviously knew about old engines, (there was a set of Austin Seven conrods on the counter in for re-metalling) that I'd stick with my original rods. I took in a new standard bush that they fitted to the good rod. They bored out the little end of my buggered rod and machined up a new bush. They then machined both bushes to fit my pins. The work was turned around in one day and cost £103, but I'm happy.
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Excellent GB, obviously not only a distinguised gent ,but a pretty damn quick one to!! Bloody well done , by the way your Crank was really looking clean and ready for business , best of luck with the start up, Bob
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Hi GB
I hope you have not forgotten to fit the nut inside the crankcase mouth thats missing in the photo above?
*pull hair out* *pull hair out*
John
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What is that boss with a hole in the middle ?
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What is that boss with a hole in the middle ?
It's part of the mechanical breather mechanism. The cork disk behind it seals the pressure until the hole in the part you mention rotates and opens to release crankcase pressure.
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G'day Roy.
To add, it's driven by the peg on the cam pinion. The cork that GB mentions fits on the pinion first and the breather runs against the inside timing cover. The cork comes in various thicknesses so there is just a little crush to make it all seal. Crankcase fumes go in red arrow, travel up yellow arrow, take a left at green arrow, travel across cases and exit in front of g/box sprocket.
Cheers
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Thanks for the explanation, was wondering what it was when fitting my belt.
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We have a problem Houston! *sad2*
I've got the head on and started to adjust tappets. When any of the valves are set, (8 & 10 thou) the engine will not go over TDC. BUGGER! It seems valves are touching pistons!
So, now I'm wondering about this later, 356 camshaft that I've put in. This engine has low comp slightly dished-top pistons in an iron head. Are you sure that combination is ok?
I wondered if I could somehow have mucked up the cam timing so I've had a check that the pistons are at TDC while a pair of valves are 'rocking', and yes, they are.
I've used a copper gasket, which I guess is slightly thinner than the composite original type. Could that be the issue?
Oh well, I'll take the head off and have a look-see.
Just had a thought: I've also fitted new cam followers. They might be incorrectly sized and lifting valves too high.
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I assume the engine turned over before you put the head on? (had a problem with my last rebuild, turned out to be timing side bush not machined square, shop sorted it for free).
Quick check ease the barrells up just enough to put some 16th/8th shims (washers?) equal both sides back and front and gently try to turn it over, might just save a bigger teardown
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I've double checked valve timing is correct. Still no-go. Head is now off. I cannot see any evidence of valves touching pistons, but then I was only rotating the engine by turning the back wheel so no hard impacts were made. I did wonder if maybe the 356 camshafts used different cam followers but the parts book says no.
I have another copper head gasket, so I could try fitting two to increase clearance. I also have a new composite head gasket that, at least before tightening down, is thicker. I think I have another cylinder base gasket so doubling them up might help.
Advice, please!
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I assume the engine turned over before you put the head on? (had a problem with my last rebuild, turned out to be timing side bush not machined square, shop sorted it for free).
Quick check ease the barrells up just enough to put some 16th/8th shims (washers?) equal both sides back and front and gently try to turn it over, might just save a bigger teardown
The engine turned over as it should when I just slackened off the tappet adjusters. It does seem as though the valves are kissing the pistons.
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Hi GB
I hope you have not forgotten to fit the nut inside the crankcase mouth thats missing in the photo above?
*pull hair out* *pull hair out*
John
When I reviewed the photos I thought, "Did I put that nut on". I did!
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I'm going to stop for a while and get some tea, and then take the dog for a walk. Maybe I'll think of some obvious reason for this problem that I've overlooked.
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I have another copper head gasket, so I could try fitting two to increase clearance. I also have a new composite head gasket that, at least before tightening down, is thicker. I think I have another cylinder base gasket so doubling them up might help.
...maybe better to find and fix the cause than treat the symptoms ?
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I've been studying the BSA parts list. Here is a possible explanation of the problem. Pushrod lengths: The Plunger A10 uses part No's 67-360 and 67-362. The Star Twin and Shooting Star uses part No's 67-979 & 67-977. I've fitted a camshaft intended for the Star Twin & Shooting Star. The cam I have now has higher lift, so maybe the pushrods I have are too long. Anyone?
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I have another copper head gasket, so I could try fitting two to increase clearance. I also have a new composite head gasket that, at least before tightening down, is thicker. I think I have another cylinder base gasket so doubling them up might help.
...maybe better to find and fix the cause than treat the symptoms ?
You are right of course. I've promised the organisers that I'll try to get to the Norfolk BSAOC camp, but it looks like I may not be able to sort out the problem before the weekend.
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The cam I have now has higher lift, so maybe the pushrods I have are too long. Anyone?
That makes sense GB.
When I put a high lift cam in my Trans-Am, I had to fit shorter push rods.
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Hi GB,
My 2 cents worth,
If you can get slack in the tappet adjusters then I dont think the problem is too serious,
Loosen the tappets right off and see will the engine turn over?
If not next loosen the rockerbox and raise it up 1/4 in, then check if the engine turns
If the pushrods have not sat into the followers or rockers properly then the engine will jam as it is turned
I do not know why but the pushrods seem to like NOT sitting into their proper places *????* *????*
John
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agree with charterlea25 I once had one sitting on the very edge of a rocker cup and didn't know about it until I heard a twang when I was pulling the rocker box down, this was in the seventies and when I stripped the engine a couple of years later I found a bent push rod which explained what had happened
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Hi GB,
My 2 cents worth,
If you can get slack in the tappet adjusters then I dont think the problem is too serious,
Loosen the tappets right off and see will the engine turn over?
If not next loosen the rockerbox and raise it up 1/4 in, then check if the engine turns
If the pushrods have not sat into the followers or rockers properly then the engine will jam as it is turned
I do not know why but the pushrods seem to like NOT sitting into their proper places *????* *????*
John
Mmm, yes, that seems possible. With my bright torch I could see that the rocker caps were all located. I'll refit the head and rocker box and make sure the push-rods are in the cam followers properly. Fingers crossed that is the problem.
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greybeard I drop oil into the cam follower cups and put pushrods in then lift them out and feel the suction its a good way to find they are in
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Right, I've had my tea and done my duty by the dog. I now feel quite hopeful that John, (chaterlea25) has the answer.
I'm going back out to the shed, (at 20:30). I may be gone some time!
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I don't know how much higher your cam is lifting, but I had to change valve springs as well because they were getting coil bound.
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Hi GB,
Roy has a point, did you replace the valve springs?
There have been some badly made ones on the market lately
II had a similar issue wit a B33 a few years ago, I had fitted goldie scrambles cams, but one spring had an extra 2/3 turn of wire even though overall length of the spring was correct
John
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I've been studying the BSA parts list. Here is a possible explanation of the problem. Pushrod lengths: The Plunger A10 uses part No's 67-360 and 67-362. The Star Twin and Shooting Star uses part No's 67-979 & 67-977. I've fitted a camshaft intended for the Star Twin & Shooting Star. The cam I have now has higher lift, so maybe the pushrods I have are too long. Anyone?
*????* *????* *????* I don’t see how the length of the pushrods or cam followers have any influence on the valve lift. If the followers or rods are too long or too short you’ll run out of adjustment on the tappet adjusters that’s all. If you can obtain your 8 or 10 thou play when the valves are closed and they are to far open when fully open it can only be the cam lifting them to high.
Another possibility is that your pistons don’t have the cutout for the valves.
I don't know how much higher your cam is lifting, but I had to change valve springs as well because they were getting coil bound.
Or that may also be possible.
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Hi GB, very sorry to read you’ve hit a snag.
I did wonder about valve clearance & springs in one of my earlier posts if using camshaft 356. (edit: reply no 50).
According to my parts list camshaft 356 was used for 1960-62 A10 s/a as well as A7SS, A10RR, it's pt no 67-0356 and the pushrod are 67-0360 inlet & 67-0362 exhaust (so are just renumbered 1954-59 A10 Plunger nos 67-360 & 67-362). Same pt nos also for 1958-59 A10s. So they're the same parts from 1954 right through to 1962 for A10s.
Tappets & springs are also the same from 1954 to 1962 for all std A10s.
Not sure but I have it in my head (from many moons ago) pushrods lengths for A10s are 8 1/2” and 9 1/2”. A7s being shorter. I'm sure someone will be able to confirm that - or not?
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i would double check your valve timing before you do anything else. valves should not touch pistons whatever the cam. maybe your camshaft is bad pattern.
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I've been studying the BSA parts list. Here is a possible explanation of the problem. Pushrod lengths: The Plunger A10 uses part No's 67-360 and 67-362. The Star Twin and Shooting Star uses part No's 67-979 & 67-977. I've fitted a camshaft intended for the Star Twin & Shooting Star. The cam I have now has higher lift, so maybe the pushrods I have are too long. Anyone?
It’s a while back but when I compared the 334 cam and the new 356 cam (from srm) I was surprised how little extra lift there was, from memory less than 020” so I doubt this is your cause of your problem?
As an aside I actually “complained” to srm who explained they had run out of 356 cams and the “emergency” batch they made was based on a blank not 100% correct, which resulted in the slightly lower lift to std, it was only a few thou so they thought I would not notice I guess. They offered to replace it but as I had already waited months for them to make a batch of cams, I kept it.
Edit: I know the problem goes away when tappets are slackened but thought I’d mention the classic error of the front primary chaincase bolts hitting the crank......just in case you moved these?
Edit: The lift I meant was cam, e.g the difference between cam base circle and cam lobe measurements. The valve lift is greater, as the rocker has “arms” of unequal length.
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The 500 pushrods are of course shorter than the 650 ones. The difference in lift of the 356 cam is miniscule - I really can't see it causing the valves to hit the pistons. There has to be another explanation. Coil bound valve springs are a possibility. A good night's sleep and a few more cups of tea will help. Don't rush it.
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G'day GB
I agree with morris in that cam followers & push rods won't make any difference. Roy and John have a point on coil bound valve springs. I put a 357 in the A7 plunger without any problems with springs (just the cam rubbing the case in the trough). Std A10 valve lift 0.265", 356 = 0.301", 357 = 0.338". General rule is that at full lift you should be able to compress the spring another 0.060" till it's coil bound.
Cheers
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......Edit: I know the problem goes away when tappets are slackened but thought I’d mention the classic error of the front primary chaincase bolts hitting the crank......just in case you moved these?
Good idea but Plungers don't have those (two very short studs carry the chain tensioner where the S/a rear bolts go )
GB- does it jam up both sides on each respective cycle or just one ?
just a quick look at the cam timing suggests that no valve is *fully* open at TDC....also for what it's worth, I think I recall discussion with B-Bill when I was doing mine, about the rocker arms being longer on the adjuster side than the 'cup' side- maybe worth considering when calculating travels (?)
General rule is that at full lift you should be able to compress the spring another 0.060" till it's coil bound........
So I guess you'll be measuring the pushrod lengths now?? *smile*
I've a couple of hours solid looking 'wet-stuff from the sky' heading my way very soon, so won't be doing much today....not that's much help to you.... *smile*
*edit; Yes I have a 357 cam in my Plunger, but also have an Alloy head with S/R springs, and I dunno if those springs would fit in a iron head, but others will know *conf2*
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At top dead center on the exhaust stroke both valves are partially open and you should be able to push the valve down a further 0.06" as well.
Cheers
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Thanks guys. I went back to the shed. I am still getting the same problem! I made sure the push-rods were in their cam followers before I put the rocker box on. I got fed up and had a drink and a bath. As BlackSheep says, a good night's sleep may get it sorted tomorrow. I'll be checking for coil binding in the valve springs.
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I've always found the top cups are mostly the problem and the inlets more than the exhaust even though the ex are harder to see.
Cheers
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At top dead center on the exhaust stroke both valves are partially open and you should be able to push the valve down a further 0.06" as well.
Kinda what I had in mind.... *conf2*...
I've always found the top cups are mostly the problem and the inlets more than the exhaust even though the ex are harder to see.
I found the 'hard to see' ones can be just visible over the top of the shaft/s ( maybe with a bright pinpoint light and small mirror if necessary) a bit of a jiggle shows if the rods are in ok....
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I have a new small super bright torch; using that it's possible to see that the rods are in the rocker cups. Not so easy to see the bottom of the pushrods.
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It looks like the problem is binding of the valve springs: with an inlet rocker fully down I cannot get a 3 Thou feeler between the coils! What to do about this; that's the next question.
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It looks like the problem is binding of the valve springs: with an inlet rocker fully down I cannot get a 3 Thou feeler between the coils! What to do about this; that's the next question.
a. Change the cam.
b. Machine the cylinder head spring seat
deeper (.050” to .075” max) with the
appropriate Crower spring seat cutter
https://www.crower.com/media/pdf/valvespring.pdf
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If I set the tappets to 30 thou the engine turns ok. I'm thinking about doubling up the solid copper head gasket, just to get me going for the weekend. The copper gasket should add about 30 thou to the clearance. Thoughts?
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If I set the tappets to 30 thou the engine turns ok. I'm thinking about doubling up the solid copper head gasket, just to get me going for the weekend. The copper gasket should add about 30 thou to the clearance. Thoughts?
But won't you still have the same problem when the tappets are set to the correct size ?
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Thanks for coming back with that Roy; of course you are right. BUGGER! Now I'm considering taking metal off the springs!
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Thanks for coming back with that Roy; of course you are right. BUGGER! Now I'm considering taking metal off the springs!
Looks as though you are looking for .060" from somewhere.
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G'day GB.
I was just about to post what Roy said. Yes the extra gasket will let it spin but you still need another at least 40 thou. The head and barrels must have been excessively decked in the past.
So the only new parts to the valve train is the cam and followers, still with the old valves and springs. Discount the followers as they won't affect it other than tappet adjustment.That leaves the cam lift is too much. Machining the spring seat and or the lower valve spring cup will give a bit more spring bind clearance but not help with the valve/piston clearance. To get it going you would need 3 possibly 4 head gaskets *eek*. Then that upsets the rocker/valve geometry. Lani at https://coppergaskets.us/ makes my special head gaskets for the through bolt motors and can make std A10 head gaskets up to 1/8" thick.
Where did that cam come from?
Cheers
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The only place that I can see for (shortening the spring) is by making more room for it by removing metal from top/bottom spring seats, cutting the head seats deeper or reducing the amount of lift (more docile cam).
Are all BSA springs the same length and wire thickness ?
Slightly thinner wire gauge could cure it.
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I've just removed 60 Thou from each of the outer valve springs. When I've got the head & rocker box back on I'll give you an update.
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To get it going you would need 3 possibly 4 head gaskets *eek*. Then that upsets the rocker/valve geometry. Lani at https://coppergaskets.us/ makes my special head gaskets for the through bolt motors and can make std A10 head gaskets up to 1/8" thick.
Where did that cam come from?
Cheers
The only thing that a thicker head gasket would help is if the valves were hitting the pistons, it wouldn't help the coil bind.
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Are all BSA springs the same length and wire thickness ?
Am I right in thinking S.Rocket springs are thinner wire
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Just a thought but the coil binding problem may have been “hidden” by the worn cam (which would have had less lift than std). The coils binding (and high spring pressure) may have even been the cause of the excessive cam wear in the first place?
Maybe the valve stems are shorter than standard, maybe the springs are wrong *dunno* but shortening the springs may get GB to the ball (rally).
If this issue has not been experienced by others, it may require further investigation......
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Do you know how many times I've had the flippin top-end on and off this bike?! I'm getting pretty nippy at it. I'm glad I bought the 3/8 socket driver adaptor for my battery drill; I'm running the loosened bolts in and out with it.
Taking 60 thou off each outer valve spring has made no difference to the engine not turning over when I start to set the tappet clearances. With a valve fully open I can now get a feeler gauge between the coils. I don't think the inner springs are binding; putting the spring assembly between the vice jaws and closing it up, looks like the inner spring does not close up when the outer does.
Ok, so, I'm back to fitting two copper head gaskets, to at least test that idea.
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Just a thought but the coil binding problem may have been “hidden” by the worn cam (which would have had less lift than std).
The reconned camshaft was fitted along with new cam followers, valves, guides and springs when I did the engine up six years ago.
The coils binding (and high spring pressure) may have even been the cause of the excessive cam wear in the first place?
*sad2*
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Just a thought but the coil binding problem may have been “hidden” by the worn cam (which would have had less lift than std).
The reconned camshaft was fitted along with new cam followers, valves, guides and springs when I did the engine up six years ago.
The coils binding (and high spring pressure) may have even been the cause of the excessive cam wear in the first place?
*sad2*
What you are saying is that there is nothing different/new in the engine that wasn't there before you started the rebuild.
If so, it should go.
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I wonder if you could make/machine the top-cap/collet grooves a bit closer to the valve tip, would depend on how much is there to play with...?
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If it's not coil bind, are you sure that your pistons aren't touching the valves.
If it turns over when you increase the tappet gap (not pushing the valves down so far).
Put some clay on top of the pistons to check the clearance.
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Are all BSA springs the same length and wire thickness ?
A Group 1954-1962
A7, A7SS, A10, outer springs all pt no 67-439, inner springs all pt no 67-440. (for 1960-1962 just add a 0 after the hyphen).
A10RR, A10SR, are different, outer springs 67-0884, inner springs pt no 67-0883.
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I know the springs and collars & collets/keepers are different for SR, and apart from head size, I'm not sure if the valves *may* have slightly longer stems also....big can ' worms there *conf2*
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Is the timing out making your valves touch the pistons ?
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Does anybody want an old motorbike? It's just out there near the bins; help yourself!
I'm knackered and have given up until such time as I find some enthusiasm or insight into this problem. I can only think the camshaft that I bought is either not compatible with this engine or has been incorrectly made.
I assembled the top end with doubled up copper head gaskets - No difference. I've tried setting the tappets really wide; 30 thou - no difference.
The symptoms are: turning the engine over by rotating the back wheel, (in 4th gear); engine goes almost full circle but comes to a stop when a rocker is fully down.
When I can raise the enthusiasm I'll take the head off again and put engineers blue on the piston crown to see if the valve(s) are touching.
Some more pictures:
1) Thank you to whoever suggested using rubber bands to hold the rocker cups down. It makes getting the pushrods in a lot easier.
2) Also, thank you to whoever suggested putting soft wires around the pushrods to manipulate them into position as the rocker box is lowered.
3) Here is my valve spring shortening machine
4) Checking dynamo belt tension by twisting to 45°, as advised by Dynamo Regulators Ltd.
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Is the timing out making your valves touch the pistons ?
Roy, I did wonder about that but I've removed the inner timing cover to check the marks on the gears.
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I'm not sure if the valves *may* have slightly longer stems.
A10SR valves have a different pt no to the other A Group models but I don't know how they differ.
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Surely if valves, push rods, followers etc are longer, it would only make a difference if there were no tappet clearance. As there is clearance isn't the problem elswhere? Or am I missing something ?
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G'day GB.
I just went back to page 1 and read for an hour! Beforehand you said with 30 on the tappets she turned over. Now with two head gaskets and 30 on the tappets she doesn't *????* The only thing I can think of is something has dropped into the cam trough and is jamming the cam. *dunno*
Cheers
edit: or the key is missing on either the crank or cam pinion.
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G'day GB.
I just went back to page 1 and read for an hour! Beforehand you said with 30 on the tappets she turned over. Now with two head gaskets and 30 on the tappets she doesn't *????* The only thing I can think of is something has dropped into the cam trough and is jamming the cam. *dunno*
Cheers
Nope can't be that; the engine turns free without the head on.
I'm so tired of this that I may be making mistakes about tappet clearances. I'll get back to the problem when I've left it for a couple of days. My faculties may have returned by then!
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see my edit ^^^
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Surely if valves, push rods, followers etc are longer, it would only make a difference if there were no tappet clearance. As there is clearance isn't the problem elswhere? Or am I missing something ?
Tappet clearance is set when the follower is on the flat area, not when the cam is lifting the follower/tappet/valve.
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...or the key is missing on either the crank or cam pinion.
Hmm, I'll have to check them. TDC does seem to coincide with a pair of rockers, 'rocking' though.
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GB, in BSA Twin Restoration book it specifies for:-
356 camshaft: Inlet open 42, inlet closed 62, exhaust open 67, exhaust closed 37.
334 camshaft: Inlet open 30, inlet closed 70, exhaust open 65, exhaust closed 25.
Are you timing it as before when you had the 334 fitted? Look at timing it as a 356.
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In the same Book valve spring lengths for A7, A7ST, A7SS, A10, 1951 - 1962: Inner 1.531, Outer 1,875.
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In the same Book valve spring lengths for A7, A7ST, A7SS, A10, 1951 - 1962: Inner 1.531, Outer 1,875.
Is that the installed length ?
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Thats the free length Roy in decimal. In inches inner spring 1 17/32" and outer spring 1 7/8".
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Hi GB,
I think I can see what the problem is??
First though, what shape groove is on the valve stems?
semicircular or a parallel reduced portion?
From your photos there appears to be too much valve stem protruding up from the valve caps
also the collets are not sitting far enough down into the caps
I had a thought earlier that maybe the top collar/collets were hitting the tops of the guides
I came across an A10 head where the components were mixed up and Super rocket valves and collets were fitted to
iron head valve caps, they do not fit correctly
The collets themselves maybe too thick??
If you take a valve cap and collets and assemble them off the engine will the collets hold the cap solidly without "rock"
The taper should hold the cap from falling
I am wondering now if this problem existed and contributed to wearing the reprofiled cam ????
John
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Hi GB,
I think I can see what the problem is??
First though, what shape groove is on the valve stems?
semicircular or a parallel reduced portion?
From your photos there appears to be too much valve stem protruding up from the valve caps
also the collets are not sitting far enough down into the caps
I had a thought earlier that maybe the top collar/collets were hitting the tops of the guides
I came across an A10 head where the components were mixed up and Super rocket valves and collets were fitted to
iron head valve caps, they do not fit correctly
The collets themselves maybe too thick??
If you take a valve cap and collets and assemble them off the engine will the collets hold the cap solidly without "rock"
The taper should hold the cap from falling
I am wondering now if this problem existed and contributed to wearing the reprofiled cam ????
John
Wow, you guys are great; while I've been out for a walk with Janet and the dog you've all been scratching your heads on my behalf!.
The collets are something I will be checking.
What about Rogers idea about different cam timing? I guess if that cam requires different timing there must be a camshaft pinion to go with it. I'll check the parts book.
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One thing I'll ask GB is if you can measure the length of your pushrods, if it's no trouble ?
Sorry duTch, I forgot about that but I'll be seeing the pushrods again soon and I'll try to remember to measure them.
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Surely if valves, push rods, followers etc are longer, it would only make a difference if there were no tappet clearance. As there is clearance isn't the problem elswhere? Or am I missing something ?
Tappet clearance is set when the follower is on the flat area, not when the cam is lifting the follower/tappet/valve.
Thats what I mean. If the valve is hitting the piston but you have clearance when on the base circle, surely all thats left is either coil bound or cam lift.
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Hi GB,
I think I can see what the problem is??
First though, what shape groove is on the valve stems?
semicircular or a parallel reduced portion?
From your photos there appears to be too much valve stem protruding up from the valve caps
also the collets are not sitting far enough down into the caps
I had a thought earlier that maybe the top collar/collets were hitting the tops of the guides
I came across an A10 head where the components were mixed up and Super rocket valves and collets were fitted to
iron head valve caps, they do not fit correctly
The collets themselves maybe too thick??
If you take a valve cap and collets and assemble them off the engine will the collets hold the cap solidly without "rock"
The taper should hold the cap from falling
I am wondering now if this problem existed and contributed to wearing the reprofiled cam ????
John
I see what you mean, if the caps are being held down by the collets, that could cause coil bind.
It has not yet been confirmed that the valves are hitting the pistons.
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I guess if that cam requires different timing there must be a camshaft pinion to go with it. I'll check the parts book.
Looked at my parts list and they have the same pt nos 1954 - 1962, cam 67-337/67-0337, idler 67-335/67-0335, crank 67-339/67-0339.
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sorry to jump in without reading all the posts,,, greybeard have you got the timed breather and cork washer and inner timing cover on... if you havn't the cam is wandering as I learnt and jamming two valves together hope this helps, ps I have not been to the pub
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sorry to jump in without reading all the posts,,, greybeard have you got the timed breather and cork washer and inner timing cover on... if you havn't the cam is wandering as I learnt and jamming two valves together hope this helps, ps I have not been to the pub
Hmm, interesting. I had the inner timing cover off when I first noticed this problem but It's been off today while I've been testing. I don't get this though: The cam has a flange on the inside and the pinion fixed on the outside so cannot really wander, (as long as there is not a huge amount of endfloat).
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After checking the pinions I compared all the pt nos for 1954 - 1957 A10 s/a and plunger valve gear with 1960 - 1962 s/a models valve gear. All use the same pt nos except for valves.
1954-57 A10: exhaust 67-324, inlet 67-323
1960-62 A10: exhaust 67-0743, inlet 67-0742
In addition the A7SS and A10SR, which also use the 356 camshaft, have even different pt nos again for the valves.
That's the only difference I could find between the valve gear. What the actual difference is in the valves I don't know - but there must be a difference.
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mmm tricky one this you could do with someone helping and 4 eyes are better to make two brains work, I do know when dry building my spare shooter engine with 357 cam to get none binding springs[ long story modified head with SR inlets standard exhausts ] I was turning the engine without everything in situ and eventually found the cam was riding two followers at a certain point and jamming two valve heads together , it took me ages to find out by using a good torch down plughole. it could also be it wasn't meant to have a 356cam like my shooter wasn't meant to have 357 without lots of things to put right to make it work, even srm knew when I told them what I was doing that they had to supply me with ground down bottom valve spring holders so I didn't get coil bind on the innlets and I had to take out some from where the collets fit on the exhausts to raise the spring height and stop those binding , some people had to remove metal from the cam trough when fitting a 357 I was lucky I didn't but I had a 4 day MARE trying to get valve gear satisfactory.
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After checking the pinions I compared all the pt nos for 1954 - 1957 A10 s/a and plunger valve gear with 1960 - 1962 s/a models valve gear. All use the same pt nos except for valves.
1954-57 A10: exhaust 67-324, inlet 67-323
1960-62 A10: exhaust 67-0743, inlet 67-0742
In addition the A7SS and A10SR, which also use the 356 camshaft, have even different pt nos again for the valves.
That's the only difference I could find between the valve gear. What the actual difference is in the valves I don't know - but there must be a difference.
Are there any part numbers on valves ?
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That's the only difference I could find between the valve gear. What the actual difference is in the valves I don't know - but there must be a difference.
My bit; Reply 192
I know the springs and collars & collets/keepers are different for SR, and apart from head size, I'm not sure if the valves *may* have slightly longer stems also....big can ' worms there *conf2*
Without being a camshaft expert, I suggest the opening closing time difference is only due to fatter profiles at those points, and the fatter duration at TDC may vary a bit, but I'm running a 357 (with Ally head), and it works fine for me with 7.25:1pistons
GB, if the springs *are* binding, you may have missed my suggestion;
Reply 189;
I wonder if you could make/machine the top-cap/collet grooves a bit closer to the valve tip, would depend on how much is there to play with...?
Modify message
chaterlea-Johns idea sounds familiar and worth a look....
** bergers' idea got me thinking that before I finally put my barrels on properly,( because I gouged a cam-bush- yep with the key), I left the lifters out and had a look down the tunnel to ensure that the cam is running central and all the lobes are running true to each own lifter- no clipping, but as you didn't change bushes it should be fine *eek*
** berger got in while I was writing...but same-ish story..... then Roy
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I agree with the earlier comment the valve stems seem to be sticking out of the top collet a long way (which may cause coils to bind, and the jamming issue), has anyone got a pic of their head/valves handy, for comparison?
When I said earlier the valve stems could be too short, the same effect could be caused by the collet recess in the stem too far down the stem, or for that matter incorrect collets or spring retainers (or all 3!).
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Here is a random pic of a plunger head (allegedly) taken of the net, I’ve no idea of its history, but it might shed light on the matter, or confuse things further!
Certainly the gaps in the coils seems larger, but there is a fair bit of stem above the top collar....
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...... the same effect could be caused by the collet recess in the stem too far down the stem,..................
^^ that agrees with my comment above (#218) & in reply #189, (also in bergers comment)
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have a good 334 camshaft and thought i would never use that as the lobes have hardly any lift on them. but it reads like greybeards top end has been set up for that particular camshaft. do you have a photo of your old camshaft ?
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have a good 334 camshaft and thought i would never use that as the lobes have hardly any lift on them. but it reads like greybeards top end has been set up for that particular camshaft. do you have a photo of your old camshaft ?
The one I've taken out had been re-profiled. It's knackered so no point in a picture of it. I have the camshaft I took out six years ago which is a lot better than the reconned one. I'll take pictures next time I'm in the shed.
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GB, I would think that the camshaft is not the problem, I have fitted a 356 in my '55 Flash with flat top pistons and no problems whatever.
I would look very carefully at the valves and springs, the springs look very heavy without much clearance between the coils as fitted.
I think that the camshaft wear can be attributed to these springs, I wore out a cam many years ago with the wrong springs fitted.
Also, as John pointed out, there seems to be excessive valve stem above the top cap. Maybe an idea to remove the valves and springs and compare them to originals if possible.
Just my two-bob's worth.
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G'day fellas.
Just got up and read the reply's since my last post.
The A10 iron head and the A7 iron head and A7SS alloy head have the same collet and collar set up different to the SR so valves and collet/collars can not be mixed. Aside from the cam profile the timing of the cam is controlled by the keyway and is placed in the same position on all shafts.
I agree with John, the collets are too proud of the collars and too much valve tip protruding. The collar may well be hitting the top of the valve guide. This is the same as before but the slightly higher lift of the 356 may be causing the lockup. After market valves, collets etc often show inconsistencies to genuine. Collets "should" come in pairs and mixing them can create problems.
I had this once when fitting a wild cam in my A7SS racer. I cut 1/8" off the top and all was good, no coil binding and no valve and piston kissing.
The cam does have end float and is held in position by the cork and inner cover. Without these the cam can move outwards enough for two lobes to contact the same lifter (had that happen when experimenting with the breather) also causing lockup.
In my last rebuild (dropped valve) I used SR valves and collets in the 54 A7SS head but had to remachine the taper in the collars and use the iron head springs, the SR springs became coil bound..
So in saying all that you need to check collar to guide clearance. If the lockup is happening when the valve is nearly fully open John has found the problem. If this is the case lop 0.06" off the top of the guides.
Cheers
Ps: Trev got in 1st
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..... If this is the case lop 0.06" off the top of the guides. ......
I can see your point regarding colllets, but can't see that will fix any coil binding, whereas machining the collet groove further up to the tip will do both, and it seems to be (more-or-less) agreed there's enough material to do that
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o yes those coils seem way to close , just had a look at the picky [after all this time] and compared it to one off the net, with the bigger cam she will be coil bound , the bounder
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GB has already taken 60 thou off the length of the springs to get over that problem.
Cheers
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mmmmm seems very close on those coils something is very wrong as we know, maybe as dutch says and what I did on mine might help. machine the top of the valves where the collets fit to lift the top collar and face off underneath the bottom collar more *work*
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Here some pics of parts lying around. A small fin a10 head with bottom collars, and springs I think are from a later head but fit the collars ok.
I bought a basket case with several head and spring sets, but bought new springs and these were left over, but I’m fairly sure they are a10, apologies if not *conf*
The outer springs are 1” I.d. And the longest is 1.96”. Wire dia 0.147”.
The spring compresses to 0.875” before binding, in the vice.
Edit: the spring lying crosswise to the others is slightly smaller I.d and made with thicker wire, it could easily be made to fit the head but binds at 1”l long.
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Gone back again and found I missed this "The symptoms are: turning the engine over by rotating the back wheel, (in 4th gear); engine goes almost full circle but comes to a stop when a rocker is fully down.". Indicates collar hitting top of guide. I also agree the coils of the spring are too close. What is the free length of those springs? Lengths are as Roger quoted 1.53" and 1.87".
Wow, on page 16 *eek*. See GB we do luv'ya.
Cheers
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hi guys, GB, this is probably the silliest observation yet but i see a gap at the bottom of the spring and retainer, i know some of these retainers need to be fitted a certain way, is it possible that the retainers are up the wrong way, this is probably way of of the problem, so good luck with the answer you will find it in the end, cheers
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GB, I fitted a valve and springs to head to compare with yours.
Kiwi, the bottom cup can only be fitted one way as it has recesses for the springs on the top side. There is a shoulder on the bottom to keep it clear of the head.
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It is noticeable that GB's collets are not seated as well as Trevinoz.
If the collets are hitting the top of the guides, could you not file a little off the top of the guides or modify the collets.
If there is coil bind, when the top retainer is allowed to come to the top of the collets that will give a 1/16" more spring clearance.
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Good onya Trev, saved me taking a few pics *yeah*.
Just took the covers off the plunger to check a few things. Although it's an SS the valve train is the same as A10GF. At TDC with both valves rocking I can push them down at least another 1mm. At full lift I can get a mm feeler between the coils easily and push the valve at least a mm till it hits the guide. This is with a 357 cam and low comp 7.5:1 pistons.
So it may be a combination of wrong valve springs, dubious valves (too much stem above the collets), collets not seating far enough in the collar and compounded by a higher lift cam. As mentioned the previous cam and follower wear would be attributed to these faults as well.
Oh the joy of working with so called pattern parts.
The way I see it the only way to get back on the road would be as mentioned earlier to machine the valve stem to lift the collets and collar higher say 2 or 3mm.
Cheers
PS: just measured a few old valves. From top of groove (where collets sit) to tip of stem inlet 0.305", exhaust 0.320"
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Up early and trying to think out of the box (dangerous) and this may be another red herring but in 1958 the base flange of the A10 cylinder block was increased by 1/8" to make it 1/2". Did this make the whole block higher or did they shave off that 1/8" from elsewhere to make it the same overall height as it was before?
If it did end up 1/8" higher overall then everything above it was 1/8" higher and other parts would have changed to compensate.
According to the parts lists I see A10 piston and con rod pt nos changed from 1954-57 con rods 67-1203/4, pistons 67-423 to 1958-62 con rods 67-1205/6, pistons 67-1416.
Is it possible that could be causing the problem if using the later 356 camshaft with the smaller block and also it's original pt no valves? *dunno*
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G'day Roger.
I think we're all overthinking this. The flange thickness was added to the top of the flange so all the valve train stayed the same. Even a 357 can be used in a thin flange motor without any changes. The rods were changed to large journal hence the part numbers, and higher comp pistons.
Cheers
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Thanks Musky *good3*, I thought it may be a red herring but I got it into my head about 4am and I felt I had to put it forward *red*
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GB - not important now, but for the record, I think grinding the Springs shorter was a little preemptive and not such a good idea- but good at the time *pull hair out*...mainly due to potential loss of spring preload, which may or not be regained by cam lift, but maybe not where it's needed at 'rest'....this can if need be alleviated if necessary with shims later on I guess... *dunno2*....
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Guys, I love you! The person who first came/comes up with the answer gets a big wet sloppy kiss from me.
I'm strongly suspecting the 'Collets hitting the guides' theory. I may assemble the head with only the inner valve springs so I can see what's going on. I agree, my valve stems do seem to protrude further than they should. I'll check that I have collets that match the valve stems. I'd hate to take metal off the guides and holding collets against the bench grinder would be fun! However, I'll do something. I may take my valves to my engineering shop and ask them to grind the collet step further up the stem.
duTch, I'll get some new valve springs if their length turns out to not be the problem.
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G'day GB.
What length are those springs?
Cheers
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GB, Have you ruled out valves touching pistons? If not a thin layer of blue tack laid on their tops would be clean and safe and would show up the slightest dent.
(Edit) Same would go for the guides etc.
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(offtopic, will be deleted)
comes up with the answer gets a big wet sloppy kiss from me
*warn* warning: do not risk being subjected to this, do not post the answer... lol
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https://www.youtube.com/watch?v=1lsQfTaStcs
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https://www.youtube.com/watch?v=1lsQfTaStcs
Yeh, I get it!
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GB, Have you ruled out valves touching pistons? If not a thin layer of blue tack laid on their tops would be clean and safe and would show up the slightest dent.
(Edit) Same would go for the guides etc.
I have not ruled anything out Roger. I have some engineers blue, https://en.m.wikipedia.org/wiki/Engineer%27s_blue that I could put on the piston to see if the valves get marked by it.
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Jeez GB what a ball ache this part of the rebuild as turned into for you ,best of luck over the weekend ,Bob *good3*
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Jeez GB what a ball ache this part of the rebuild as turned into for you ,best of luck over the weekend ,Bob *good3*
TD, I'm expecting to find that I've made some stupid schoolboy error!
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Right then, Friday morning, (the day I should riding to Norfolk!). First thing was a good tidy up. I'm not very good at keeping my work area tidy while I'm working. I don't have very much room so the workbench and hoist were covered in tools, oil, paper towel, rags, bits of BSA etc. etc. A clean bench helps to focus the mind, doesn't it.
Musky, the springs were all about 1.873". I took 60 thou from each one, so now they are around 1.813".
duTch, the pushrods, (from SRM) have the length printed on them. Have a look below
edboy, here is a photo of the two old camshafts that I have. As you can see the reconditioned camshaft and the followers are pretty well buggered! The other one may well be the original item.
The stems protrude 9/32", (just over 1/4").
The collet design is deffo not correct for these valves. They work OK, as you can see in the fifth picture but may well be too low on the stem, which may be a problem now with this slightly higher lift cam. I found an image of some NOS collets for sale on Ebay. They are much shorter!
The Inlet valve that I have the springs off can open 1/4" before the collet touches the valve guide.
While I've been writing this I've had the idea of, while the head is on the bench and the springs are removed of checking valve protrusion inside the combustion chamber when depressed and seeing if it's possible for the valves with only 1/4" of travel to touch the pistons, which do not come to the top of the bore at TDC. More later.
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WOW, wrong collets.
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WOW, wrong collets.
Indeed! With the previous camshaft that I fitted six years ago, I either ignored them as they worked or didn't notice. See, schoolboy error on my part! *sad2*
I've contacted C&D Autos who are about 10 miles from here; they have a set of original style collets. When Wifey returns with the car I'll make my way over there and get them.
If they have new valve springs I'll buy some.
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...I had a thought earlier that maybe the top collar/collets were hitting the tops of the guides
I came across an A10 head where the components were mixed up and Super rocket valves and collets were fitted to
iron head valve caps, they do not fit correctly
It's looking like the big sloppy wet kiss is coming your way John! 😋
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If I were you John I'd leave the country p.d.q. *eek*
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Both collets are wrong. The NOS ones are Norton or suchlike. The springs don't look right either. Lucky man being close to C & D. Best spares supplier there is. Did you take the head across with you to show what's needed?
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Both collets are wrong. The NOS ones are Norton or suchlike. The springs don't look right either. Lucky man being close to C & D. Best spares supplier there is. Did you take the head across with you to show what's needed?
BS, (is it OK to address you as BS?) The picture of those collets is from an ebay seller; not C&D. The chap I spoke to at C&D instantly understood where I was coming from and assured me that he has the correct collets. *smile*
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Thanks Musky *good3*, I thought it may be a red herring but I got it into my head about 4am and I felt I had to put it forward *red*
Roger, I'm feeling pretty guilty if you are losing sleep over my problems!
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G'day GB.
I'm not sure the fat lady is singing yet, maybe just warming up.
Good idea to take a spring with you as I think you need a thinner wire and or less coils. Pick up a lotto ticket on the way as you are very lucky not to have dropped a valve using those SR collets.
Great to see your getting there.
Lucky John is across the ditch in Ireland.
Cheers
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i have not been to the pub, wow super pocket rocket collets can't get my breath. what an episode all must end well *smile*
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I've been measuring how far the valves protrude into the combustion chambers when open, (no springs) with these incorrect collets. Both Inlet and Exhaust show about 1/32" only. The pistons do not come right to the top of the bores, plus, the pistons have small crescent-shaped cutouts beneath where the valve edge would be, plus, there is the thickness of the gasket. There is no way at the moment that the valves could touch pistons! So, that's ruled that worry out.
I'm almost certain that these dratted collets are to blame!
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GB, Have you ruled out valves touching pistons?
Yes, Roger, I have now.
Come on Wifey, I need that car to get some new collets! C&D's is too far for me to use the bicycle!
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Hi All,
Lucky John is across the ditch in Ireland.
*wink2* *wink2* *wink2*
Gb Count yourself VERY LUCKY that the valves did not drop in to say hello to the cylinders/pistons *pull hair out* *pull hair out*
It never ceases to amaze me what actually stays together and runs ok (ish) *eek*
Todays problem for me on the HD J engine is that there is no free play on the side exhaust valves
It has new valves, tappets and adjusters,
It looks like I need to shorten the valve stems and tappet adjuster threaded end then thin the locknuts as well *work*
John
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Gb Count yourself VERY LUCKY that the valves did not drop in to say hello to the cylinders/pistons *pull hair out* *pull hair out*
It never ceases to amaze me what actually stays together and runs ok (ish) *eek*
The collets seem to grip the valve fine. There is an annular bulge on the inner face of the collet that engages with the top of the cutout on the valve stem. Could the valve really have disengaged itself? Do you think the wrong collets have caused, (or contributed to) the destruction of the camshaft? The valve guides do not show signs of hammering on their ends.
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Todays problem for me on the HD J engine is that there is no free play on the side exhaust valves
It has new valves, tappets and adjusters,
It looks like I need to shorten the valve stems and tappet adjuster threaded end then thin the locknuts as well *work*
I guess HD here means Harley Davidson. Sorry, I know nothing about those machines. Is there a nice friendly forum, like this for HD's?
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http://www.harleytechtalk.com/
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Good you've found a likely culprit, but as Musko says 'The Fat Lady.....'. It's hard to tell for sure if those are SR collets, as there are others with same profile that are a bit smaller, like the ones I had until I realised they and my caps and springs were all wrong- SR collets are significantly larger...but none of that matters for now
I was going to ask if you'd changed any thing in the valve gear on your earlier rebuild, but kind of assumed that all would have been as standard due to your long ownership- maybe a PO changed it ?
As suggested, I'm sure you'll take the whole shebang with you to C&D's- if not already back...in the missusGBmobile *smile*
Off topic, but Good luck with the HD John- is that the Cannonball one?
Todays problem for me on the HD J engine is that there is no free play on the side exhaust valves
It has new valves, tappets and adjusters,
Could that be from many re-cuts ?
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In my rush to get to C&D's before they shut, I forgot to take the head with me. However, I think all will be well. Here are pictures of the new collets.
Picked up a complete set of valve springs while I was there.
If I can slip out to the shed this evening I'll get as much done as I can.
L8rs!
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In my rush to get to C&D's before they shut, I forgot to take the head with me. However, I think all will be well. Here are pictures of the new collets.
Picked up a complete set of valve springs while I was there.
If I can slip out to the shed this evening I'll get as much done as I can.
L8rs!
That looks more like it GB. *smile*
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Hi GB,
The collets valve cap and valve stem should assemble into a solid chunk of metal
The inner collet groove should fit the valve stem reduced portion exactly
The taper should grip the valve spring cap without any "rock" sideways
Sorry for polluting this thread with the HD issues *red*
It would seem that suppliers produce one set of spares to cover lots of years when there were probably several changes during production ??
Yes the valve seats have been recut but not excessively
Time is getting tight to get it sorted before shipping to USA during the 3rd week of July *eek*
If I had my time over I would probably have kicked this thing to touch, *problem* *problem* *problem* 's with every
part I go near
I could probably fill twenty something pages on a forum if I had time to write it all up *eek* *eek* LOL
Give me a BSA any day
John
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Yeah, what Roy said- looks much better, hope it does the trick- probably a bit late to find a machine shop to grind the groove higher if need be...hopefully not.
John- there'll be heaps easier spares when you make it over there *smile*
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G'day GB.
Were those collets in it from day one of your ownership? Yes they could have jumped out if you ride like I do *eek*.
The only concern I have now is that the collars may have been bodged to take the SR collets. Fingers crossed.
G'day John. The wife often reminds me of my swearing & cursing every time I have a HD in my shed.
Cheers
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hi guys, WOW what a mission for you GB from a couple of the smallest parts in the engine to cause such a major problem. looks like you are nearly there hope your health is not suffering and that you still have some hair left, CHIN up as you have `met the challenge`, cheers
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I've just finished putting the top on the engine and adjusting the tappets. Engine spins freely!!!!
God's in his heaven — All's right with the world
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*woo* *woo* *woo* *wink2* *loveit* *loveit* Well done. Off to the show tomorrow.
Edit - NOT off to the show tomorrow *sad2*
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You guys have been fantastic during this ordeal. Edboy sent me a pair of conrods, refusing any payment! Mr Butch even offered to lend me a bike to use for the BSAOC camp! And Irish John, (chaterlea25) wins the prize, (and the kiss) for identifying the cause of the problem. It's ludicrous isn't it that the cause of so much head scratching was eight cheap little widgets?
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hi guys, WOW what a mission for you GB from a couple of the smallest parts in the engine to cause such a major problem. looks like you are nearly there hope your health is not suffering and that you still have some hair left, CHIN up as you have `met the challenge`, cheers
After I realised I was not going to be able to do the BSAOC camp at the weekend I relaxed; that helped. I have to finish putting all the other bits on the bike but that's hopefully, business as usual.
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Were those collets in it from day one of your ownership?
I cannot remember, but probably.
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*wink2*
right... now back to bussines you lot... *smile* *smile*
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Well done GB, that was a very interesting project. I am just the same, these parts have been in the bike for years with no problems. Then someone gets it right and you think why did I not see that. *pull hair out*
ELLIS
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hi guys, GB i believe that John (Chaterlea25) will be in your area soon so he can collect his reward, ha-ha, cheers
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Excellent news GB *smile*. I can just imagine your relief when it turned over ok.
*respect* who sussed it!
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Well done GB *smile*. Not comment before as nothing useful to add. I thought about offing the A10 for the Norfolk camp (not far from me) but thought I would check insurance first basically got a no from them so that became a nonstarter.
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Hi GB, good to hear you have sorted it out, *smile*
But I think it is very important to have this topic under a different heading, as it would not come up if you where searching for a solution for a problem of the engine not turning over after rebuild, maybe one of the moderators could sort this out?
Cheers *beer*
Peter
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Well done GB *smile*. Not comment before as nothing useful to add. I thought about offing the A10 for the Norfolk camp (not far from me) but thought I would check insurance first basically got a no from them so that became a nonstarter.
What a star to even think of offering! I guess you didn't go.
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G'day GB.
What do you think of Peters suggestion?
Cheers
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Hi GB, good to hear you have sorted it out, *smile*
But I think it is very important to have this topic under a different heading, as it would not come up if you where searching for a solution for a problem of the engine not turning over after rebuild, maybe one of the moderators could sort this out?
Cheers *beer*
Peter
Yes, I was thinking the same thing. I might summarise the details in another post. No one will want to wade through 20 pages to find all the relevant points.
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Thanks mate. My brain is frazzled replying to Anji!
Cheers
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I've made a start...
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I think this is one of the most engaging threads I've had the pleasure of reading! 20 pages in the blink of an eye, with so many people trying to help out.
Well done GB and all of you stars!
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I think this is one of the most engaging threads I've had the pleasure of reading! 20 pages in the blink of an eye, with so many people trying to help out.
Well done GB and all of you stars!
I'm happy that you enjoyed it Paul. There were times when I did not enjoy it!
Yes, this forum really works; chaps from all over the world chipping in with ideas until the problem was identified. Fan-bloody-tastic! *smile* *smile* *smile*
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glad your now sorted greybeard. i m amazed you got around with the engine in its previous state . now you should find a whole new bsa experience in front of you called the middle lane of the motorway. 65 mph should do it.
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Thanks Ed. I haven't had a chance to finish putting the bike back together yet, I may get permission to visit the shed today.
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edboy I like your comment because the bike will be better of course. I bought mine off a friend in the seventies and I think the crank snapped in 1980 returning home from Silverstone. of course being brit iron it was still running and i didn't even know it had snapped. when I took it apart the cam and followers were just like grey beards and ithad a million more horrors . once rebuilt it became a bit of a growling beast *smile*
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i ve always followed the idea that the larger lift on the camshaft lobe would take longer to wear out. so longer period between rebuilds.