The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: BSAnders52 on 26.05. 2017 22:49
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Hi, Referring to my long introduction, if you read it I dont have to tell more abot the circumstances.
http://www.a7a10.net/forum/index.php?topic=11737.0
Symptoms and diagnosis, this is where i need some feed-back.
The bike started fine, or at least willingly. Oil was ouzing from the RH side of the rocker hous and spurting out of the crankhouse ventilation. Oil was pitch black, and even felt somewhat thicker than its original SAE 50. It appeared to have passed through the combustion and then down to the sump..
There was a distinct tick-tick for every turn (of the camshaft?) wich to me tells there is something snagging or bent, or..
We took off the outer transmission cover, and took out the generator chain, to eleminate it as a source of the ticking. Ticking remained
I used a screwdriver as a stethoscope to find out where the noise come from..
Digging deeper , removing the inner cover, the ticking was traced to the cam area.
Compression test reveiled the LH cylinder to be hold twice as much as the RH.
The oil pump feels like the culprit, not able to keep the flow or pressure.
Or maybe it is the other way around, the oil bypassing the valves, getting too thick and too full of carbon deposits, makes the oil pum to fail..
Anyhow, I have not yet had the time to remove the head and look further into this.
I hope the bronze main bearing is OK, it sounds like it is. All bearings seem to have escaped any dammage. So far..
I likewise hope all dammage is in the accessible parts - pushrods, lifter, valves.. and not on the camshaft. Is this just wishful thinking? Possibly.
I would like to not have to split the engine, but probably it is better to know everything is OK, and then close it, than to hope there are no hidden dammages in there.
I will order a new Oil Pump from SRM, they seem to he the most recommended. I seem to have to leave allso the cylinder head to them for rebuild and modification to accept non-lead fuel.
Or is there any other workshop that can do this job, who hav all necessary tools and jigs, and the knowledge? Cosmo in Hastings?
The only remaining workshop in Sweden is due to close down, and he is unwilling to take on more jobs.. I might be able to talk him over..
There are a coupple other workshops, that only do Norton or Triumph, and claim making the tools for BSA would cost more than the rebuild itself..
Any opinions? Tips
I will be back with pics, when I have them, but I will be off to Holland for some time first..
Anders
Sweden
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Possibly put some oil down the bores and re do the compression test, if the pressure improves it most likely means valves are the problem, rather than pistons/rings.
Edit: if pressure improves it means Pistons or rings are most likely the problem not the valves. The oil will i improve the seal on the piston but not improve the valves if they are leaking.
Ref the oil pump, the operating pressure is (worryingly) low in these engines once the oil is hot, the pressure relief valve is designed to prevent "over" pressure only when the oil is cold, and does not open when the oil is hot. The standard pump is not often found to be worn, they last well.
if you are lucky the tapping noise might be a bent or stuck push rod *lol* alloy ones in particular can get the end stuck in the rocker.
I think the jury is still out on modifying valve seats for unleaded, iron heads do not seem to need modifying, alloy heads maybe.
My guess is burnt valve, maybe partial seizure. Both can cause a tapping noise and low compression.
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Anders,
Oil blowing out the breather port is likely due to excess oil in the sump. This could be because the pump is not pumping it out or because it drained down ("wet sumped") while sitting. It would be nice to know if you saw oil returning to the tank while running. If you did, it is very unlikely the problem is the pump. While you can't go wrong with an SRM pump, you could hold off buying it until you reveal the tick-tick noise and cause of gushing oil. That noise is not the pump and pumps are easy to change later. Tick-tick could be as simple as a loose valve adjuster (we wish).
As for the color of the oil, pitch black would not surprise me after a run the length of Sweden.
As for modifying the head for unleaded, regardless of the debate over it being an issue, using lead substitute should guarantee that it's not an issue and you could forego the seat replacement, maybe, forever.
KiwiGF,
Uh, is there a glitch in what you wrote or in my understanding? For more than 50 years (which doesn't mean I'm right), I have understood that valves are the problem if compression DOES NOT improve when oil is squirted in the cylinder, the oil sealing leaking rings but not leaking valves.
As always, I am warily expecting any correction which may come.
Richard L.
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Anders,
KiwiGF,
Uh, is there a glitch in what you wrote or in my understanding? For more than 50 years (which doesn't mean I'm right), I have understood that valves are the problem if compression DOES NOT improve when oil is squirted in the cylinder, the oil sealing leaking rings but not leaking valves.
As always, I am warily expecting any correction which may come.
Richard L.
Richard you are quite right even though I know the correct method I put it the wrong way round, senior moment eh *problem* it's now edited ......hopefully clearly.
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I honestly thought you just glitched in the way you wrote it and figured you were well familiar with this old trick.
Richard L.
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The drastic loss of compression on the right hand cylinder is either valve or piston problems.
With black oil pouring out of breathers etc. I would strongly suspect a failed piston.
I would not go messing about with oil pumps at this stage. The oil pump is not the problem.
Off with its head!
Once the head is off, it should be obvious where the problem lies. Pouring paraffin down the ports will show immediately if a valve is not sealing properly. In any case, with the head off I would take the valves out and do the normal clean and lap in anyway.
If the valves are OK lift the barrels. There will be a problem with the RH piston or rings. Place a rag over the crankcase mouth as you lift the barrels in case any pieces of piston or ring try and leap into the crankcases.
The screwdriver stethoscope is notoriously inaccurate. Sound can propagate wonderously through engines. What sounds like a cam may well be a piston.
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Richard & Kiwi I thought the same ^^^, when I read it earlier *shh*...thanks for easing my mind
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Thanks a lot for thoughts.
I too am open to find the cause elsewhere than in the oil pump. Lifting the top will reveil the truth, but I am not sure I will have the time until a few weeks ahead..
As I dont have handbooks at hand, is there any special I must think of, any procedure I must follow when I lift the head? I simply cant remember, too long since last time..
This is how it looked then, 1978-ish . (http://)
How do I use the "INSERT IMAGE" button? It is boring to have all pictures at the end, after the written text..
I will definetely come with more pics and questions.
Anders
Sweden
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Nore: Anders posted just before me, so please take that into account.
The drastic loss of compression on the right hand cylinder is either valve or piston problems.
With black oil pouring out of breathers etc. I would strongly suspect a failed piston.
I would not go messing about with oil pumps at this stage. The oil pump is not the problem.
Off with its head!
Once the head is off, it should be obvious where the problem lies. Pouring paraffin down the ports will show immediately if a valve is not sealing properly. In any case, with the head off I would take the valves out and do the normal clean and lap in anyway.
If the valves are OK lift the barrels. There will be a problem with the RH piston or rings. Place a rag over the crankcase mouth as you lift the barrels in case any pieces of piston or ring try and leap into the crankcases.
The screwdriver stethoscope is notoriously inaccurate. Sound can propagate wonderously through engines. What sounds like a cam may well be a piston.
Black Sheep,
First, would you mind sharing your first name? I'd rather not start abbreviating your name as "BS", because it would NOT apply.
I think your diagnosis is probably right on, but I have a couple of questions/points. I know I have done compression tests where the cylinders vary widely, only to come back (rested maybe) and run another test where everything is fine. Therefore, maybe we can't rule out a faulty test. If the piston has a hole in the top I would expect no compression as opposed to half, but maybe other modes of failure apply.. Then, about the rag covering the crankcase, I would have thought that piston pieces falling off was a sign the whole thing needs to come apart. Needed or not, if it was mine I'd have to do it for peace of mind.
Richard L.
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How do I use the "INSERT IMAGE" button? It is boring to have all pictures at the end, after the written text..
Ha! True confessions: After over 3000 posts here I still haven't bothered to figure it out.
Not sure about special tricks when removing plunger head. For my swingarm, it helps a little to remove the top-rear center valve cover stud to ease rocker box removal. You might want to loosen the valve adjusters before loosening the rocker box. Not mandatory, though.
Richard L.
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Ah, yes, that rings a bell..to remove one of the studs to be able to free the rockerhouse off the upper frame tube.
Thanks
I will analyse everything before I start ordering parts.
Anders
Sweden
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Pouring paraffin down the ports will show immediately if a valve is not sealing properly.
I had to stop for a minute and think about this before I realized that Black Sheep was speaking British and not English. I then figured out he was referring to kerosene and not candle wax. *conf2* *smile*
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Casting aside my anonymity, my name is Gordon and I'm a bagpipe playing Scotsman. A Cracked piston may still give some compression. Pistons can fail in a number of interesting ways. I have a number contributed by my Norton over a number of years.
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Hi Anders, You'll get to the bottome of it.....
Quote from: BSAnders52 on May 27, 2017, 23:40:21
How do I use the "INSERT IMAGE" button? It is boring to have all pictures at the end, after the written text..
Ha! True confessions: After over 3000 posts here I still haven't bothered to figure it out.
Well I thought I'd have a go, so clicked on it and copied a pic from my docs and pasted it in.....>
(http://IMG_20160828_23676.jpg)
(http://IMG_20160828_23676.jpg).........< there twice, but it did nothing. *dunno*
(it looked like this>
(http://IMG_20160828_23676.jpg)
(http://IMG_20160828_23676.jpg)
<,in the 'reply' pane-without the 'quote' )... and when I come back to modify it, the 'insert 'stuff is still all there.......*dunno* all a bit ghostly I say, but maybe best to leave it for another place...
IMG_20160828_23676.jpg
NB- ^^edit/Edit/Edit ^^
B.Sheep- I think the first Monty Python I ever saw was the Big marauding Scotsman episode
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I just finished playing further with no result ... *bash*
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G'day Anders.
The tick tick coming from the cam area is probably just back lash in the gears. Especially noticeable when turning the motor over by hand or kickstart. If the tappet clearances were ok that would be it.
Definitely piston and or ring trouble giving excessive crank case pressure which would also create the rockerbox leak.
Cheers
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Well, well, well, finally I could not resist the temptation. I cant go on and just ponder and speculate..
Took off the rockerbox and cylinder head.
Genttlemen, manny of you were very right, and I too had come to have the same suspicions, the main dammage is in the RH cylinder, caused by a loose gudgeon pin! Both circlips seem to have desintegrated and the pin is gnawing a deep gash in both sides of the cylinder.
The entire inner surface of the valve house is covered with a sticky, allmost rubbery deposit, in the push rod shaft it appears like charcoal debris.
I suspect this is to be found in the entire engine, in all oil ducts and pipes..
Alreaddy this talks for the engine to be split.
And the conrod may be dammaged as well.
I did not continue with lifting the cylinder, the hour is very late, I have found the dammage corresponding to the symptoms, however I have not yet seen it all..
Good night, or rather good morning
Anders
Sweden
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Hi Anders, yep a top and bottom strip down and clean is needed, and you may as well check the condition of all the various bearings whilst it's in pieces.
It looks like the engine may have been left a very long time without being run. I'm sure someone will now mention the "sludge trap" in the crank ! (Only a small one, in a small journal crank)
Good pics *beer* but sorry to see the damage *help*
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Ouch, yep, that'll do it.
Full strip time. Bore till clean then see what piston size you need.
The rod MIGHT be OK and just need a little end bush. Get them checked and if only the slightest bit out throw them away.
Commiserations.
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Yes, yes, yes, I am aware I will have to tare it down to the smallest item..
Someone mentioned in an erarlier input, that theese iron headed motors dont need to be specially treated or rebuilt to work with modern un-leaded fuel. Is this correct? Do they not even need lead substitute added? Or did I mis read that?
Beeing without a workshop manual for the moment, what are the different over sizes for pistons/ bore? Of course they are not in metric millimmeters to start with, but theese cylinders are 71,5 mm = 2,815 ". Is this on the high end or on the lower end of possible over dimensions? I have no idea what size they were 40 years ago, but I cant remember I had it rebored.., I think I had new pistons installed.., aah dont know.
When I restore one of all theese JAWA engines that float through my workshop, I do as a rule replace all bearings, just to know all are new and in the same condition. All clocks are on zero. I guess I ought to keep that habit allso here. It is impossible to determine wich bearings are OK and wich need replacement, apart for those obviously dammaged.
Are all bearings easily obtainable? I know theese imperial measure bearings can be tricky to find..
Is there any other easy improvement that can be done while the engine is anyway taken apart?
Reworked or completely new oil pump is still on the list.
I guess a normal service of the cylinder head will do. And continue with lead -substitute..
Clutch seems to work OK.
Yes, that sludge trap, where is it? Any picture?
Until later
Anders
Sweden
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It may have been an old circlip re-used or a new one mistreated (bent) or not fully fitted. Or a square-section clip in a round groove.
Or- your bores may not be perpendicular to the barrel base, or the crankcase top face may not be parallel to the crank bearings, or you may have mis-matched crankcase halves, with a step on top, where they meet.
Any of those alignment issues, especially combined with detonation, and/or play in the big ends, can hammer the pin and circlip out.
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Anders, if it's any consolation, it isn't as bad as when mine did the same thing- groove about 1/16" (1.6mm) deep *eek*
what are the different over sizes for pistons/ bore? Of course they are not in metric millimmeters to start with, but theese cylinders are 71,5 mm = 2,815 ". Is this on the high end or on the lower end of possible over dimensions?
Standard bore is in fact in metric; 70mm, so 71.5 is 1.5mm O/S, (+0.060") There are apparently +0.080" available, but I'll let someone else butt in on that.
The bearings (slippers and all Roller/Ball-race bearings)are more available now than in the '70's (I reckon, in my case anyway)- cost a bit more than metric ones though....
There are cast iron body 'High-flow' oil pumps available at a cheaper price (~GB ?180 ?) than the SRM ones. I bought one and have done a few thou miles without issues, and I know Greybeard has one too (I think he twigged me to the idea)
It may have been an old circlip re-used .................a round groove.
Or- your bores ......................., with a step on top, where they meet.
Any of those alignment issues, especially combined with detonation, and/or play in the big ends, can hammer the pin and circlip out.
Geez- in my case I figured I must've just forgot to put 'em in.....
.......suddenly makes me look a bit better than I thought.*smile*.... *bash* (getting real)
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Hmm, the thought has struck me, it may very well be my own mistake that has come back to haunt me.
I have no idea if there has been any repair or work done to the pistons since it left my care..
Ah, last time there was a piston job, when I owned it, it was professionally done, I did not do it..
It was after an other similar chain of events.
But since it worked very well, for long time..
I will have to ask the present owner, if they have any records on engine work and repairs..
Doesnt really matter, it is dammaged, it needs repair. No point in trying to find out whos fault it is.
It may as well be material faults, or wear, simply..
Ahh, I just found out it most likely is allreaddy on the last over size, +.60..? Only three over sizes? Then it is reslieveing? New cylinders? Bugger.
Anders
Sweden
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G'day Anders.
A sleeve for the bores are in order as I doubt another 20 thou (0.5mm) will clean that up. I have a pair of these sitting on my bench http://www.feked.com/hepolite-bsa-a10-cylinder-liner.html
Then go back to standard size pistons http://www.feked.com/hepolite-piston-for-bsa-a10-gold-flash-650cc-models-etc-1950-62.html
Main bearings http://www.feked.com/crankshaft-main-bearing-bsa-a7-and-bsa-a10-ariel-fh-67-0670.html
http://www.feked.com/crankshaft-main-bearing-bush-bsa.html
Shims for end float http://www.feked.com/bsa-crankshaft-shim-set-a10-a7.html
While it's down check the cam & idler bushes. Replace the oil retaining ball and spring (also known as the anti wet sump valve. Check the crank pins for size and grind to the next size if required. Put new shells in.
The sludge trap is inside the crank pins accessed by the big grub screw in the crank web. Look here at the two minute mark https://www.youtube.com/watch?v=5VH1vwK5_k4 yours if a small journal won't have the radial bolt or a tube.
That'll keep you busy foe a while.
Cheers
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*eek*That film about the sludge trap was a horror movie!
I certainly expect something similar in this engine. If not else, this convinced me I am in for a complete overhaul. Down to the bone.. and back.
I vaguely remember the crank has been in for a total refurbishment at some point. But again, that is very long ago..
You are probably right about the sleeves.
I have found your site last night googeling, feked.com, but you are in AU. Reasonable prices, but the postage for theese heavy things will cost a fortune. Hmm, I am going to Sydney in winter, to see my daughter, maybe a bit too late.. I dont plan to be back very quickly.. as long as the visa will allow me.
I would like to have this fixed before I leave.. but with no hurry.
Oh gosch, why was I entangeled in this..
Life is a slow surprise..
Anders
Sweden
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Amazing just how easily that sludge trap came out. If only they all did that.
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Anders,
It seems the natural place for you to check out for parts would be basmotor.se. You probably won't get all you need from them, or any one source, but the postage for their parts should be tolerable.
Richard L.
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Anders,
Feckd are in the UK.
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Hi Anders,
A click when turning the engine slowly over can be heard, the valve springs force the follower to turn the cam to take up the backlash in the timing gears,
On engine faults that develop into a downward spiral :(
Lack of oil changes and or high mileage leads to wear on the timing side bush
This results in low oil pressure, that does not open the PRV to supply oil to the cam trough
The first signs of problems are usually increased valve clearances due to worn cams and followers
Shrapnel from the cams and followers is thrown upwards and gets stuck between the pistons and bores leading to scoring and rapid wear
further shrapnel gets picked up from the sump and carried to the oil tank,
then back to the oil pump and into the ever decreasing cycle of destruction *problem*
Unless you dismantle the engine completely and clean everything especially the crank sludge trap and then scrupulously clean out the oil tank, you are wasting money fitting a new oil pump
John
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Anders,
It seems the natural place for you to check out for parts would be basmotor.se. You probably won't get all you need from them, or any one source, but the postage for their parts should be tolerable.
Richard L.
Anders,
Feckd are in the UK.
I know them well, ,Basmotor they live just near by from me. They are well reputed, so most likely I will try to use them as much as possible = no postage.. ;)They dont stock any new oil pump though, just re-worked used original pump, as an exchange service. You give them your old and get a new-ish instead. Maybe I can get them to order one for me.. a new one.
Aha, I got it wrong. It was very late in the hours when I found Feckd, when they are in UK they are within reasonable distance. I might even go to UK this fall.. Yet another reason to make it real.
Thanks for all good thoughts so far.
It will be a very serious rebuild, of the whole engine. Dont worry.
Btw, the present owner has put a magnetic bolt in the sump lid. It had done its magic, had a big wad of steel filings. So at least that debris did not "recycle" in the lubriction system.
I might even be inspired and eventually start to put my 1971 Royal Enfield Interceptor S2 together..I do miss to have a British twin to roar about with. But the RE is quite another animal than the docile BSA. And there are two decades between them.
Drems, dreams
I will have to deal with reality first.
Anders
Sweden
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A few years ago Dutch and me bought new high-flow pumps from John Phelan: contact details in this article.http://www.sumpmagazine.com/bsamotorcycles/bantam-john.htm
They cost about half the price of the pretty SRM pump. They are steel, rather than anodised alluminium. You could ask him if they are still available.
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Thanks for the tip. I will certainly check with him once I have the "to-buy-list" more complete.
Anders
sweden
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OK; here is the epicentrum - a somehow broken circlip.. The inner circlip, and the small piece has migrated through the hollow piston pin. Well on the RH side, it started to excavate the piston and the area it could reach when passing up and down in the cylinder, making an impressive gash..
The pin got locked a bit askew, inwards to the center of the engine, with the bigger part of the circlip, and gnawed away on its side of the cylinder..
The RH circlip is still in its groove, untouched so far.. but with very little material left to hold it.
Not a pretty sight, but very clear.
The path is clear..
Anders
Sweden
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YUK!
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Hi Anders,
There are reasons why engines spit out circlips *????*
With wire circlips the ends of the pin should be chamfered,
If the pin moves outwards it should push the circlip tighter into its groove
Wire circlips must only be used when the pistons have a semicircular groove to match
Do not use wire circlips with "ears"
If the small end bushes are not "square" to the bore and parallel to the crankpins it will lead to failed circlips
All sorts of reasons this can happen from a misaligned small end bush to a bent conrod
John
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Yeah, what John said. You know how I know this? Because John said it.
I'm just slightly amused by protecting against things falling in the crankcase. I think you'll be in there soon.
Richard L.
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Nothing fell down into the crankcase, I am sure. Both halves of the circlip were retrieved, and I had put a rag around and under before I lifed the cylinder for real..Pistons were in top position, just to have some distance to lift before someting fell down, IF there was anything that wanted to escape..
Yeah, Everything is not yet reveiled.. But it will soon show.
I am off to Holland this morning.
When I loaded the bike on the trailer, alone, it fell halfways up.. back wheel still on the ramp.
The ceiling is very low, so eventually I lifted off the canopy (? tarp tent), just to get leverage, it is hard when you are bent doubble , lots of ratchet straps is good to have
I struggeled for more than two hours, but I got it there. Could not wake up my neighbours in the middle of the night..
Nothing bent or dented, it is an off road machine.
Oh well..
Anders
Sweden
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Well, what I tried to get across with tongue in cheek is that there seemed to be no need to protect the crankcase since it must come apart, probably next. Sorry for obscure (but not last) attempt at humor.
Richard L.
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muskrat
I personally would not recommend feked in my experience they often supply the wrong parts (even by part number) and they are shall we say hesitant to give you your money back even when its their error :(
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G'day bikerboy.
I have only got the liners off them. The right ones supplied, look good and measure up.
I had their site bookmarked so was just easy to copy their address.
Cheers