The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: BSA500 on 05.11. 2015 16:03
-
I posted this in the clutch etc forum....
A bit of an odd one on a A7SS. It sounds like the chain rubs on the inner primary side case if you lean the bike to the right while the engine is running. I think there is side play on the chain anyone else had this?
Well took off primary side case and found as per title the crank has loads-by loads I mean loads-of play side to side(no up/down). I recently rebuilt the bottom/top ends so new bearings/bush/big ends/small ends and pistons. I set the play using a dial gauge to 2 thou.
It now has more play than what I started with. The strange thing is there is NO broken shims at all the oil screen is spotless, even the magnetic plug has minimal swarf on it.
Now I have taken these engines down many times so that's no problem other than I don't want to *sad2*. My actual question is about a post a while back about stripping down without disturbing too much of the rest of the lump can anyone point me in its direction I ahve a pretty good idea how to approach it but would like to check my thinking.
The bike always plays up when I start to work on the car project jealous cow
-
yes they are like that, mines sulking cos a Honda VFR is sharing the garage at the moment, *smile*. RichardL will be around soon ,he had a problem with shims so should be able to shed some light on this,sorry I can't as I opted for SRM conversion when I last restored mine, Bob
-
The times I have reshimmed over the years its the main source of issues for my bike. I suppose I shouldn't use it all year round *sad2*(We have been together 25 years)
-
Have started to remove the lump and I did find the post on removing it intact. Looks easy enough. Also the bit about not removing the top end etc to sort out the shims. Did a quick and dirty end crank measurement with the dial gauge and got 22 thou *eek* *eek*.
-
i was told many years ago to place any shims behind the main roller bearing outer race so they cant be spat out. unfortunately i ve never tried this because i ve never had right size shims. however bsa500 have you tried this method?
-
If you've had these engines down a few time BSA I'm going to be telling you how to suck eggs - apologies but this might be of help to another reader.
In theory the bearing inner rotates with the crank, the outer should not rotate at all, so shims clamped between the bearing inner and crank web should
be safe, in practise if the bearing inner rotates at all the the shims will suffer, shims placed between the bearing outer and the crankcase must be large enough to not touch the bearing inner as edboy infers I think.
Not sure I'd be happy with that method, the relationship between the thickness of bearing inner and outer has to be within spec for this application also,
Make sure you source the bearing from a knowledgeable BSA A dealer
-
Andy,
First, could you point us back to the thread about bottom-end disassembly while leaving the top end intact?
With at least 0.022" play, as you've mentioned, it is really surprising that you did not find shim bits in the sump. If the shims are intact, it makes me think that either the outer race or timing-side bushing was not fully seated when you last assembled the bottom end and now it's pushed into place. That said, I think you'll probably find the shim bits somewhere down there and we all want to know where. The last time I went through this I did find the bits in the sump.
In my case, I found that the inner race was finger-loose on the crank. That loose and there is no guarantee that the friction between the inner race and the crank will be greater than forces applied to the inner race by the rollers (others may disagree, but this just seems to make sense to me). If you're buying it, the inner race can spin and wipe out the shims. I used Loctite 641 retaining compound to keep the inner race in place on the crank and so far (about 1000 miles) it seems to be working. (I am about the furthest you can be from superstitious and still looked for wood to knock.)
Please let us know what you find down there.
Richard L.
-
Andy,
First, could you point us back to the thread about bottom-end disassembly while leaving the top end intact?
With at least 0.022" play, as you've mentioned, it is really surprising that you did not find shim bits in the sump. If the shims are intact, it makes me think that either the outer race or timing-side bushing was not fully seated when you last assembled the bottom end and now it's pushed into place. That said, I think you'll probably find the shim bits somewhere down there and we all want to know where. The last time I went through this I did find the bits in the sump.
In my case, I found that the inner race was finger-loose on the crank. That loose and there is no guarantee that the friction between the inner race and the crank will be greater than forces applied to the inner race by the rollers (others may disagree, but this just seems to make sense to me). If you're buying it, the inner race can spin and wipe out the shims. I used Loctite 641 retaining compound to keep the inner race in place on the crank and so far (about 1000 miles) it seems to be working. (I am about the furthest you can be from superstitious and still looked for wood to knock.)
Please let us know what you find down there.
Richard L.
I will try to find it but in a nutshell loosen the barrel studs put the pistons TDC and slide the barrels up. This should give enough clearance to take the drive side crankcase off and do the shims etc. A bit heavy and fiddly but better than having to remove rockerbox/head/barrels and all the gaskets etc.
I will tell/pictures of what I find but again the oil screen was spotless. I am going down the drive side bearing not properly home
-
I will try to find it but in a nutshell loosen the barrel studs put the pistons TDC and slide the barrels up. This should give enough clearance to take the drive side crankcase off and do the shims etc.
I think we mostly got that. I just thought there might be some amusing pictures.
Richard L.
-
I think the amusing pictures will come when I try this :!
-
*smile* Looking forward to it.
-
You won't be able to renew the base gasket and the pushrods will fall out of their cups when the followers drop.
Cheers
-
yes and the base gasket will tear easily when you lift or move the barrels around. the method of top end removal mentioned does sound interesting and a jig to take the weight would make it easier to lift the top end but then again replacing the barrels, head and rockerbox is sunday afternoon stuff so not really worth the aggro. shiming the outer bearing to the crankcase oil seal face isnt my idea, i was wondering if others were using that method .i.m looking forward to seeing what caused all the excess end float within 2,000 miles.
-
Base gasket can be glued together ;) always ends up leaking any way. Going to wedge the followers. I just going to give it a go, The worst is having to remove the rockerbox while the engines out of the frame. That has got to be better than doing the limbo to get the rods back in when the engine is back in.
It has only done 1400 miles so yes its a little....disappointing *sad2*. If the shims are intact then who knows???
-
Hi *smile*
I have also just found out, that the crankshaft on my 1960 A10 have about 0,3 mm sideways endplay (no play up and down). Is that normal? I suppose not *conf*
See a short video of the problem here: https://www.youtube.com/watch?v=7MdP7AL_DHM (https://www.youtube.com/watch?v=7MdP7AL_DHM)
Regards Frederik, Denmark.
-
G'day Fred.
Yes. way too much. 0.05mm is recommended, 0.10mm is maximum.
BSA500, it's going to be a bugga of a job doing it that way. Your only going to save a few hours and a couple of gaskets. And later were going to say "I told you so". Do it the right way.
My guess is either the timing side bush wasn't all the way home or the cases were misaligned and the crank wasn't free to give a proper reading the first time.
I really do wish you luck with it.
Cheers
-
or the cases were misaligned
Yes, I never use joint compound on the case halves, pointless measuring down to 0.003 " then smearing a thickness of goo into the eqation, you could put the goo in first of course but I've never had a problem withe two case halves leaking, the taper seems to do it just fine
-
Mine appears to move more than that video. Prob will have a mare doing the engine this way but I just cannot bear stripping each and every bit off esp as the head joint was an absolute b*****d last time and its still a raw and recent memory :!.
Perhaps the drive side bearing misaligned or timing bush or ???. We shall see. I will continue to remove the lump tonight while the family watches the soaps.
-
Well a little farther down the strip down road. Had to abandon leaving the clutch on as a nut on one of the engine mounting bolts was being a bitch so the inner primary case needed to be out of the way. Found the clutch centre was starting to work loose ie not very tight and the sprocket nut was loose as well so not a wasted effort taking the clutch off *smile*
-
G'day Fred.
Yes. way too much. 0.05mm is recommended, 0.10mm is maximum.
Thank. I did expect that, it must be a winter-projekt to get rid of this end-float/play *smile*
-
I'm glad this thread showed up at this time. I've been putting off reshimming one of my engines that I put together a few months back. It has .021" (.53mm) endplay. When I took it apart, it had no shims. When I put it together I used Yamabond 4 on the case halves. I think I'll try again without sealant before I add shims. Not a big deal, as I checked endplay as soon as I torqued down the case bolts, so not a lot to take back apart, I just have to do it (instead of a dozen other things I've been working on).
-
Getting closer the engine is now out-yes it is heavy with the head etc still on it *eek*
-
I'm glad this thread showed up at this time. I've been putting off reshimming one of my engines that I put together a few months back. It has .021" (.53mm) endplay. When I took it apart, it had no shims. When I put it together I used Yamabond 4 on the case halves. I think I'll try again without sealant before I add shims. Not a big deal, as I checked endplay as soon as I torqued down the case bolts, so not a lot to take back apart, I just have to do it (instead of a dozen other things I've been working on).
I can see threebond adding a little, but not much at all. Maybe .001 to .0015 but I really cant see more than that. Generally unless I am trying to seal a known bad area on something (bent cover mating area, or a screw driver gouge) I basically smear just enough on to make it glossy (very, very thin) and even that squeezes out.
It would really be interesting to read endplay dry, and then again with the threebond.
-
It would really be interesting to read end play dry, and then again with the threebond.
It would even if 0.001 was the result that is one third of the max 0.003 gone
-
I guess I didn't think about it that way Bill, I was just thinking how small an amount .001 is....
-
Well here are some pics of the strip down. Decided on a full strip as the head gasket showed signs of leaking and some oil burning(oil from the top as no blow by stains on the piston skirts). As predicted the shim was intact so I prob cocked up or the bearing was not fully home etc.....
(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2Fi11.photobucket.com%2Falbums%2Fa170%2Fbsa500%2FDSC04854_zpszfxvht6m.jpg&hash=b15b8c7a11585afc644a519a434bebd951fd0b9e) (http://s11.photobucket.com/user/bsa500/media/DSC04854_zpszfxvht6m.jpg.html)
(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2Fi11.photobucket.com%2Falbums%2Fa170%2Fbsa500%2FDSC04858_zpsxfxzt0ed.jpg&hash=8b87deec7d86b878180ee2fed66a40c566c4b55f) (http://s11.photobucket.com/user/bsa500/media/DSC04858_zpsxfxzt0ed.jpg.html)
(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2Fi11.photobucket.com%2Falbums%2Fa170%2Fbsa500%2FDSC04859_zpsp8isvusz.jpg&hash=15bd6c343d017f9a0eb5ca86c1730f0aaff02797) (http://s11.photobucket.com/user/bsa500/media/DSC04859_zpsp8isvusz.jpg.html)
So dig out my spare shims and see if I have the correct amount and put right a few loose bits and bobs
-
I forgot to add the inner bearing race is finger tight ie easy to slip on and off, always has been so I will be locking that with a punch-joking bearing retainer loctite etc ;)
-
Not related to the issue of too much play, but I'm curious how thick that one shim is. Looks thicker than the 0.010" that comes with sets I've had. Did you machine it yourself?
Richard L.
-
Nah its just an optical illusion as it measures 11 thou. I have gathered up my spare shims and have a 32 thou pack to use. I will be using bearing retainer for the inner race to,hopefully, make this a less regular event.
-
I'm not sure if it really helps, but in two of the three times I've done it, I've kept the really thin shims sandwiched between the thicker ones.
Richard L.
-
Yep i do that in the vain hope of protecting them(and a little dab of grease).
-
Hi,
At 32 thou I would machine up a solid shim
Where I worked we very often had jobs shimming electric motors to pumps some up to 300hp
Eperience taught me that a stack of shims would degrade and spread whereas a solid ship never gave trouple
HTH
John
-
I agree with John. Did we discover why the end float grew? Wear on the thrust face of the bush or did it push in further?
Cheers
-
Hi,
At 32 thou I would machine up a solid shim
Just does not seem a simple or affordable task for those of us without mills, lathes and surface grinders.
Richard L.
-
Hi Richard,
I regard my machine tools as essential pieces of equipment,
I can repair fabricate or replicate a lot of items instead of searching on the internet/phoning around and waiting a week or more for the postie to arrive (with the wrong bit *eek*)
Bike owners need to have access to people who are willing to repair or make one off items at a reasonable cost
Other than that I must be lucky that the guys into bikes around my location are exceptionally talented????
World class painters and welders / fabricators living close by.
Cheers
John
-
Ah yes, but you have a much bigger collection of odd old bikes than those of us with just one or two As. (In my case, an A10 on the road and an A7 in the works.)
Richard L.
-
I suspect the bearing drive side settled, If the bearings were a little less 'thick' that could give a little extra play as well ?
-
Hi Richard,
Ah yes, but you have a much bigger collection of odd old bikes than those of us with just one or two
Yes true I suppose,
I have had bikes since I was about 12, all cast off by others back then, and started helping out at the little local garage that did car repairs,
I did a stint at technical college that really opened my eyes to all the possibilities that machine tools offered
I then got a very old lathe that was persuaded to make all sorts of bits and pieces
In 1985 I went to work in a power station gave me the opportunities to see and learn a lot
Around 1990 I bought a lathe for home use, it needed repairs but only cost £175 back then and I'm still using it.
When early retirement bekoned 6 years ago I went in search of some more machines in order to be self sufficient at home and to offer repairs/ rebuilds to others
Its not all bike stuff either, repairs to boat parts and even work on a local tower clock !!!
Cheers
John
(Sorry gone very OT here)
-
Hi Richard,
Ah yes, but you have a much bigger collection of odd old bikes than those of us with just one or two
Yes true I suppose,
I have had bikes since I was about 12, all cast off by others back then, and started helping out at the little local garage that did car repairs,
I did a stint at technical college that really opened my eyes to all the possibilities that machine tools offered
I then got a very old lathe that was persuaded to make all sorts of bits and pieces
In 1985 I went to work in a power station gave me the opportunities to see and learn a lot
Around 1990 I bought a lathe for home use, it needed repairs but only cost £175 back then and I'm still using it.
When early retirement bekoned 6 years ago I went in search of some more machines in order to be self sufficient at home and to offer repairs/ rebuilds to others
Its not all bike stuff either, repairs to boat parts and even work on a local tower clock !!!
Cheers
John
(Sorry gone very OT here)
Why don't you live near me. Fancy moving to Kent its quite nice and I can give you plenty of pratice on your lathe ;)
-
Hi
Why don't you live near me. Fancy moving to Kent its quite nice and I can give you plenty of pratice on your lathe ;)
LOL *smile* *smile*
You would have to rely on the postie to be the connecting link??
Serioulsly if you cannot find a local machinist I could make the shim for you
Check out "Mens Sheds" in you area, a good number of these have members who "can do things"
How far are you from Ramsgate? I know Peter Bayliss at Dave Fox Kawasaki ( I know Dave too) they have a good collection of vintage bikes and would surely know local machininsts
HTH
John
HTH
John
-
Somewhat on a different scale but that has reminded me now of an issue I had with a Bantam many years ago. I had running problems which I eventually determined must be the crankcase seals, so I pulled the motor down to swap them out. I replaced the main bearings at the same time. I think that the motor was down for maybe a few weeks when I came to button it back up. I could not get the cases to pull up without the crank going tight. Ultimately I somehow managed to determine how much the interference was and had a guy press up the crank some more to take up this plus the required clearance. Bike went back together OK and was from then on OK (though the original problem remained – so not the seals then).
The replacement bearings were definitely banged home OK, and I’ve scratched my head ever since wondering how the crank managed to stretch whilst the motor was down. Overly think main bearings … surely not?
-
Measured the end play and got 29 thou and its getting chilly out there brrrrrr
(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2Fi11.photobucket.com%2Falbums%2Fa170%2Fbsa500%2FDSC04869_zpsg4nskjvf.jpg&hash=a76b411f1daf3c5f89c2584186af1846f12b1b98) (http://s11.photobucket.com/user/bsa500/media/DSC04869_zpsg4nskjvf.jpg.html)
(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2Fi11.photobucket.com%2Falbums%2Fa170%2Fbsa500%2FDSC04864_zpsm6jxfsh6.jpg&hash=c4f2b8b8256f40782f68680f18e00572633a9304) (http://s11.photobucket.com/user/bsa500/media/DSC04864_zpsm6jxfsh6.jpg.html)
-
Hi
I bolt a steel plate to the DS case , bolts fit into the primary case screw threads
Magnetic base for the dial gauge sits on the steel plate
The way you show in the photo can lead to errors
HTH
John
-
That's just the rough and ready measure the proper one is yet to be done *smile*
-
Clamped the bottom end in a vice and secured the dial gauge to the pillar drill table and still got the reading of 29 thou movement. I repeated the reading many times and always spot on for 29 thou. I feel my main issue is with the drive side bearing being an easy slip fit on the crank. Allowing the inner race to turn against the shims and wreck them. I shall use the loctite type stuff and see how we go *smile*
-
Allowing the inner race to turn against the shims and wreck them.
Some fettle this by peening the crank, not something that I'd be happy with but maybe there are members here with a more professional view
-
The bearing inner race is not 'sloppy' in its fit, no play, just doesn't require a puller to get it off like other people have reported.I will be trying the loctite 461 or other type of bearing 'glue'.
-
Hi BSA500,
If the cush drive nut is properly tightened how the bearing can move relative to the crank and chew up the shims, is the question *????*
If there is miniscule space between the shaft and bearing (sliding fit) I can see engine vibration and driving foces overcoming the clamping force of the cush drive nut leading to wear on the softest item (the shims)
I do not think "loctite" is a permanent repair *sad2* Remember heat softens loctite type products
So solution's ??
1) have the shaft built up and remachine to press fit ?
This would be the "perfect fix"
2) instead of placing the shims between the crank and bearing, fit shim between the bearing outer race and crankcase,
At least this would not result in more chewed up shims ?
3) Attempt the loctite repair and have to repeat it again in a couple of thousand miles if you are lucky *problem*
My 2 cents worth
John
-
Over the years the time between shim chewing has varied quite alot with no obvious reasoning. I have been riding this bike for 25+ years and the cush nut has never been loose so hopefully we can ignore that.
I think that some bearing inner races may have been a little tighter by a few thou depending on supplier and that may have saved some shims. I only noticed the shims were chewed this last time when I took it down for a rebore no other indication like vibration just a lack of power.(not a lack of smoke :! ).
I shall try the loctite 641 (not 461 duh) as the crank work is a little out of my budget(none) and finding someone local is a chore-there is one company but the prices are eye watering *eek*.
Just to add I have had many thousands of miles before the shims went over the years its just working out why some fail early-this time it wasn't really a fail as it appears that a)I'm a tonka and mis measured or b) the bearing shifted which is still my fault-probably
-
The ID of the inner race should not vary anything like as much as a few thou, it must surely only be tenths. But it’s an interesting point – if you could either find a bearing factor who would take the time to find you one on the tight side of whatever tolerance is provided, or if you have a local tame one who would allow you a happy Saturday morning in their storeroom pulling them one by one from their packaging until you found one with a better fit. Like they're going to hold a big stock of these.
-
The ID of the inner race should not vary anything like as much as a few thou, it must surely only be tenths. But it’s an interesting point – if you could either find a bearing factor who would take the time to find you one on the tight side of whatever tolerance is provided, or if you have a local tame one who would allow you a happy Saturday morning in their storeroom pulling them one by one from their packaging until you found one with a better fit. Like they're going to hold a big stock of these.
Local bearing factors rarer than hens teeth. Brammer is my nearest one and they want your first born as a down payment.
-
Kind of figured I was probably dreaming.
I was apprenticed at Hoffmans in Chelmsford. Whenever I was helping myself to ball races off the line there I used to pick the quietest ones off the noise test rig just before they went into packaging.
-
Hi BSA500,
If the cush drive nut is properly tightened how the bearing can move relative to the crank and chew up the shims, is the question *????*
If there is miniscule space between the shaft and bearing (sliding fit) I can see engine vibration and driving foces overcoming the clamping force of the cush drive nut leading to wear on the softest item (the shims)
I do not think "loctite" is a permanent repair *sad2* Remember heat softens loctite type products
So solution's ??
1) have the shaft built up and remachine to press fit ?
This would be the "perfect fix"
2) instead of placing the shims between the crank and bearing, fit shim between the bearing outer race and crankcase,
At least this would not result in more chewed up shims ?
3) Attempt the loctite repair and have to repeat it again in a couple of thousand miles if you are lucky *problem*
John,
I am sticking my neck way out when I counterpoint with someone like yourself with sooo much more bike building experience than myself. Nevertheless, here goes.
If the cush drive nut is properly tightened how the bearing can move relative to the crank and chew up the shims, is the question *????*
I believe that, if this were true, there would be no space for oil film between the ends of the rollers and the shoulders of the races.
I do not think "loctite" is a permanent repair *sad2* Remember heat softens loctite type products
So far, it seems to be at least a 1000-mile fix, but I admit that I'm not pulling my sump plate to certify my sump is shim-free. Regarding "softening" of the Loctite, the disassembly temperature (while hot) of 641 is about 100 deg. C. greater than the operating temperature of motor oil and about 50 deg. C. more than the flashpoint of Castrol GTX 20/50. (I had to go looking up this data.)
Attempt the loctite repair and have to repeat it again in a couple of thousand miles if you are lucky *problem*
I'll report back in another 1000 miles (or sooner?) if this happens.
Richard L.
-
Richard, have a good look at the drive side arrangement. Tightening the cush nut against the splined sleeve will hold the inner race tight against the crankshaft. This has no relation to bearing clearance, i.e. end float, which is set by shims, thus giving end of roller clearance for the oil film which concerns you.
-
I chewed up the shims in my motor after about 2000 miles. The Cush-nut was loose. I removed the engine (complete) and lifted the cylinders up just enough to get the cases apart. I was able to get some more shims from the fellow who rebuilt the motor. I got the end play down to .003". I also used a Loctite Stud and Bearing mount that's good to 500 F on the inner race. I always use Loctite 518 for case halves. You smear it on with your finger, just enough to turn the aluminum red. There was no measurable change in the end play after application. Nothing squeezes out either, so the film is down in the "tenths" range. I use the same stuff of the base gasket for the cylinders. It works very well. After 1500 miles, my end play is still good and nothing in the screen. The best way to ensure proper torque on the cush-nut is to "Rope" the cylinder. Back the crank off about 90 degrees from TDC on the compression stroke and slide a good amount of thin rope into the cylinder. Turn the motor until it locks and torque the nut. This is the recommended method from Rotax and it works well on any application. As far as locking the inner race, it only needs more force than is applied by the spinning bearing. Most two-strokes have crank bearings that you heat to 300 degrees F and drop them on the crank. The interference is only a few thousandths. They wll spin at better than 10,000 RPM and hold without any problem. You would be amazed how easy they are to press off. A proper torqued cush-nut at 60 ft/lbs is more than adequate for holding the inner race in position. I used a touch of Loctite as a "Belt and Suspenders" type of thing. I'm sure there would be no problem if I didn't use it, but since it was apart I applied it.
-
Trev,
I am both glad and sorry to say that you are right, but, of course. I had to run to the garage to partially put my disassembled A7 back together to see it properly. So, is this then saying that no matter how loose the inner race is it will not spin with a well-tightened cush nut?
This leads to my next question. With a loose inner race, are we depending on friction between the compressed shims to be sure the inner race keeps turning at exact shaft speed?
Finally, should I just give up and admit that shim destruction only occrs with a loose cush nut? *????* *conf* *smile*
Richard L.
-
Hi Richard,
Trevor beat me to respond to your last Q
So, is this then saying that no matter how loose the inner race is it will not spin with a well-tightened cush nut?
This leads to my next question. With a loose inner race, are we depending on friction between the compressed shims to be sure the inner race keeps turning at exact shaft speed?
Finally, should I just give up and admit that shim destruction only occrs with a loose cush nut? *????* *conf* *smile*
Try and imagine this scenario *????*
The cush nut will clamp the bearing race and shims endwise,
Suppose there is even a 1- 2 thou radial gap between the bearing inner and crank mainshaft
The pressure holding the bearing inner depends on the friction between the end faces of the bearing race
and crank oneside and spacer on the other
I can see engine power pulling the crank towards the gearbox?
the power stroke pushing the crank downwards against the bearing?
engine vibration acting in a couple of different directions? (vectors)
I can see all these forces overcoming the clamping friction and the crank moving realtive to the beairng inner
by our supposed 1 - 2 thou
This tiny amount of movement over thousands of engine revolutions would eat away at the shims *ex*
Of course as the shims wear and clamping pressure from the nut is lessened so the shims wear more until they break up *sad2
Then you go to clean the sump filter and find the remains there *problem*
You then embark on a strip down only to find the cush drive nut loose and blame yourself for not doing it up properly *????*
When in fact it is loose because of the loss of the shims and the resultant wear on adjacent parts *ex*
Aside from the temperature considerations of using loctite,
Does it have the mechanical strength of steel to withstand the mechanical stresses mentioned above ?
I very much doubt it *sad2*
I have heard of bearing races being electro plated to increase their interference fit ?
But I have no experience of this !!
John's 2 cents worth *????*
-
Trev,
I am both glad and sorry to say that you are right, but, of course. I had to run to the garage to partially put my disassembled A7 back together to see it properly. So, is this then saying that no matter how loose the inner race is it will not spin with a well-tightened cush nut?
This leads to my next question. With a loose inner race, are we depending on friction between the compressed shims to be sure the inner race keeps turning at exact shaft speed?
Finally, should I just give up and admit that shim destruction only occrs with a loose cush nut? *????* *conf* *smile*
Richard L.
I would say that pretty much covers it. Since the inner race spins freely on the crank, the amount of diametral clearance doesn't matter. It's not a source of "resistance" when it comes to spinning. Loose is loose. Most shim stock is in the upper 40's to low 50's in hardness (Rockwell C scale), which means it's not much softer than the bearing race and definitely harder than the crank. There isn't any compressability issues going on there. It's certainly not going to distort in any way when it's torqued into place. 60 ft/lbs of torque on such a small area is a lot of force, and you only need enough to overcome the force generated by the spinning bearing. The few stories I've heard of shim destruction involved loose Cush-nuts. When I spun mine, the first thing my motor guy asked was "Did you torque the Cush Nut?".
-
Hi Richard,
Trevor beat me to respond to your last Q
So, is this then saying that no matter how loose the inner race is it will not spin with a well-tightened cush nut?
This leads to my next question. With a loose inner race, are we depending on friction between the compressed shims to be sure the inner race keeps turning at exact shaft speed?
Finally, should I just give up and admit that shim destruction only occrs with a loose cush nut? *????* *conf* *smile*
Try and imagine this scenario *????*
The cush nut will clamp the bearing race and shims endwise,
Suppose there is even a 1- 2 thou radial gap between the bearing inner and crank mainshaft
The pressure holding the bearing inner depends on the friction between the end faces of the bearing race
and crank oneside and spacer on the other
I can see engine power pulling the crank towards the gearbox?
the power stroke pushing the crank downwards against the bearing?
engine vibration acting in a couple of different directions? (vectors)
I can see all these forces overcoming the clamping friction and the crank moving realtive to the beairng inner
by our supposed 1 - 2 thou
This tiny amount of movement over thousands of engine revolutions would eat away at the shims *ex*
Of course as the shims wear and clamping pressure from the nut is lessened so the shims wear more until they break up *sad2
Then you go to clean the sump filter and find the remains there *problem*
You then embark on a strip down only to find the cush drive nut loose and blame yourself for not doing it up properly *????*
When in fact it is loose because of the loss of the shims and the resultant wear on adjacent parts *ex*
Aside from the temperature considerations of using loctite,
Does it have the mechanical strength of steel to withstand the mechanical stresses mentioned above ?
I very much doubt it *sad2*
I have heard of bearing races being electro plated to increase their interference fit ?
But I have no experience of this !!
John's 2 cents worth *????*
Just because the crank is pulled or deflected does not mean that the torque disappears. It means that it will increase the pressure on one side of the race as opposed to the other side. It doesn't eliminate it. Once again, the force that is required only has to be greater the force of the spinning bearing.
-
There isn't any compressability issues going on there.
East Coast,
A lot of interesting stuff in this. Just for clarification, regarding compression of the shims, I wasn't referring to squishing but to the affect on static friction.
John,
It seems you are saying that shim destruction is inevitable, with the inner race working its way loose regardless of an initially tight cush nut. Yes, that would be sad. Incidentally, the last time my shims got shredded I thought the cush nut was tight, but it wasn't. I don't want this to be some definitive explanation, but it does seem oddly coincidental.
Richard L.
-
Just my experience, but every time my shims have been destroyed the cush nut was NOT loose. It has never come loose EVER. Not sure where that leaves me *sad2*. I shall be trying the loctite and getting the play down to 1 thou to give me fighting chance.
-
Hi All,
Guys !!!
If the shims break up and fall to the sump, then the cush drive nut is no longer clamping the bearing inner *ex*
Suppose BSA500 loses his 29-3 =26 thou of shims, then the cush drive sleeve/spacer/ bearing inner combination
is shorter by 26 thou therefore the nut is loose by the amount of lost shims
If I could not afford to have the crank repaired
I would fit the shims between the bearing outer and crankcase instead
John
-
I would fit the shims between the bearing outer and crankcase instead
these would have to be shims the size of the bearing outer not the inner , is that right
-
HI Bill
these would have to be shims the size of the bearing outer not the inner , is that right
Yes.
John
-
I'm going to throw in a BUT here.
The shims in their proper position are (supposed to) held tight by the cush nut. If placed between the outer race and the crankcase the only thing holding is the fit of the outer in the case. I've seen more loose outers than inners. *dunno*
Cheers
-
I've had timeout due to data blowout, but sneaking in a looksee here and there...
A couple of things to note;
BSA 500 hasn't lost shims on this excursion, that was the previous one (1500miles ago)...
I had a thought that maybe the shim got caught up on the radius of the journal/web and then dislodged (maybe that's been suggested); I set mine vertical with the web supported on a 'bench', that way I figured it has a better chance of staying concentric.
I'm also presuming that the raised 'landing for the bearing inner is intact...? I discovered mine to be worn below the web due to a slipping inner, to the point where I also discovered I'd also had to machine the journal (~29mm) and add a thin sleeve with matching radius, which seems ok after ~9000 miles. I had to add extra shim to bring the worn web back to positive. (Cranks were/are scarce in my part of the world too!)
With regard to the inner slipping on the journal(which may not be relevant here), I had a thought that if the journal/web radius matched the radius on the bearing inner, it should help hold it concentric.
With shims behind the outer, would be essential to ensure they seat properly in the case of a radius in the housing, which could change the dynamics. I considered shims in there would set the outer closer to the web, but just had a look at a used bearing, and it seems to have plenty difference between inner and outer faces, so should not be an issue anyway
aaah, Musky rounded me up...and like he and others say, the nut should hold them tight, and even if it does come loose, it should only go as far as the split-pin and still have spring tension on it (not ideal- especially if the spring breaks like mine did), and I can't see why the friction of the rollers would be greater than the friction of the assembly
Stuff to doo...
-
aaah, Musky rounded me up...and like he and others say, the nut should hold them tight, and even if it does come loose, it should only go as far as the split-pin and still have spring tension on it (not ideal- especially if the spring breaks like mine did), and I can't see why the friction of the rollers would be greater than the friction of the assembly
Stuff to doo...
The spring doesn't hold pressure on the race, the spring holds pressure on the sprocket. It's outside of the assembly being torqued. The nut bottoms out on the spline sleeve, that's what provides the pressure to the inner race. It's all stacked up on the crank and the nut compresses everything. You are torquing a solid stack of components.
-
Yes E_C_B, I know that, but what I mean is there is spring tension on the sliding-bush/cam which in turn pushes on the sprocket which pushes on the collar of the inner sleeve and then the bearing inner race (not ideal).
I wrote it as an afterthought bubble 'cos Musky posted while I was writing.
-
Almost shy to ask a shim question here, having read so much on it, written so much on it, and been given so much good advice. Nonetheless, I don't recall this question being asked by me or anyone else, and if it has, there is too much info to sift through to find it.
Question is: Should we target an allowance for the minimum amount of side play before installing shims? I want to tell my machinist to dress the face of the new T.S. bushing so the crank is not locked up when the cases are assembled. I don't think it would be good if the play (without shims) was, say, 0.004". That would mean the shim (or shim stack) might be just 2-3 thou thick. Arguments for specially machined thick shims seem to support the notion that such a thin shim, by itself, is a recipe for shim destruction. ("Well, Richard, if you get your bearing on right, tight to the web and with the shim sandwiched between and (maybe) Loctited, the shim should be fine, you dummy." Then I say, "Well, yes it should, so why bother with custom-made thick shims?")
Any thoughts?
Richard L.
-
Hi Richard
Assuming the machinist is going to make a new bush from the "solid"
The casing bores are very often gone "out of round" and oversize leading to oil leakage between the bush and case
if a "bought" bush is used
If the machinist assembles the crank and drive side bearing without shims into the drive side case
it should not be too difficult to measure the thickness needed on the flange of the timing side bush to (at first ) give negative endfloat, then skim the bush face to .000-003end float
If the machinist is very confident that they could hit zero endfloat they could machine the bush flange to that thickness
before fitting
That would be the absolute best engineering solution (blueprinting) and no shims required
John
-
G'day Richard, John.
My thinking would be to give it 1 to 1.5 thou endfloat to allow oil to lubricate the thrust faces.
I'll be doing this on the A7 rebuild (when I get a roundtuit).
Cheers
-
Here ya go
-
I have a sense that asking the machinist to take on perfect crankshaft endplay without shims would lead to quite a lot of extra cost from that machinist.
Back to my original question: if you must use shims, what minimum thickness would you choose for shim stability?
I'm going to remove the old bush and measure ovality. If it's a problem I'll have to return my phosphor bronze part and see about getting one with an oversized OD, or having one made. I have neither the lathe nor the skills.
Richard L.
-
G'day Richard.
The thinnest shim I have is 1.5 thou and would be happy to use that as long as the bearing is snug on the shaft and the cush nut is done up correctly. Once we get into big #'s (20+) I'd suspect something not right. A single shim is preferable to a stack but IF assembled dry and correct a stack will work fine.
Yes a lot of extra $$$ to make a bush with the thrust face a measured thickness. If the case is out of round a bush will need to be made anyway (I don't know of oversize off the shelf).
Another way of thinking is the motor was designed with a bush thrust thickness of a certain thickness. Everything revolves around this. OK the thrust face will wear over time (amount depends on time/lubrication) or the crank grinder may face the thrust surface of the crank. If we're only talking a few thou it can be taken up on the bearing side.
Check the case. If OK throw the new bush in and shim as we have done for 60+ years.
Cheers
-
Richard,
I know a lot of machinists.
Explain to him everything you know you need out of the set-up, what numbers would be perfect, dont tell him how to do it, and then let him go.
These guys get bored to tears cutting the same parts over and over and over.
Your project could be an exciting challenge to the guy. In the least its a break from cutting air over hydraulic solenoid adapter plates or automatic dog food dispenser door hinges *smiley4*
Lee
-
Thanks for good advice. Keep it coming.
Muskrat, your suggestion last time I did shimming has, so far and with much wood knocking, worked well. Specifically clamping bearing and shims against web with cush nut while Loctite sets.
Coater, I don't think my machinist, Custom Engine Services of Aurora, IL, is spending much time on doggie door hinges, or the like, but your advice to state the goals is good. I will be asking for 1.5 -15 thou end play to give them a challenge while keeping it affordable.
On ovality, my small bore gauge turned out too small and my large too large to measure the bushing bore. This left me with telescoping gauges. Using one of those it appears the bore might be 1-1 5 thou oval. Might not matter because new bush is about 4 thou bigger than old bush and about 6 thou bigger than the bore. That, I believe, amounts to an oversized bush. I think I should ask machinist to just round the bore and turn the bush for the right fit after the heated case has cooled. I am assuming he will heat the case to install the bush, just like we would.
Wow, I hope a couple of our machinists have read this far and will tell me if my plan is good.
Richard L.
-
I've just had a crank refurbed by a local firm. The big ends were fine but the timing side bush was about 2 thou out of round so I just asked them to recut the journal until it was round. They reckon they took about 6 thou off in total to get it clean and straight. I used a -40 solid phosphor bronze bush and line reamed it until the crank was a comfortable fit - I reckon I skimmed about 3 thou out. The crank spins really nicely when installed and I've checked vertical play with a dial gauge and a soft lever under the end of the crank. To get the endfloat correct I use the same method as Musky, i.e locking everything together on the drive side (without the cush spring), mount the crankcases in a vice and check endfloat with a dial gauge fixed to the vice. I've skimmed the outer edge of the crankshaft nut so that it will pass through the drive side bearing - makes life easier not having to keep taking the nut off. Like Musky I fit shims and loctite the bearing and tighten the nut until I fit the primary drive.
-
Guys, I have followed this whole string on crankshaft end float with great interest as I posted a recent question on this subject.
What an incredible amount of information it contains and more importantly some very useful tips when I come to set the end float on my A7 in the very near future.
I can't help but wonder what it was like on the BSA production line in the 50's and 60's when these engines were being mass produced - surprised they
achieved such and good reputation and reliability especially winning the Mauds trophy as they could not have built them to the accuracy that we can with all the time in the world.
So thanks again for all the technical advice, I will put it to good use.
-
I can't help but wonder what it was like on the BSA production line in the 50's and 60's when these engines were being mass produced - surprised they
achieved such and good reputation and reliability especially winning the Mauds trophy as they could not have built them to the accuracy that we can with all the time in the world.
Yes, and the same reasoning applies to the rocker cover. You would not want to be on piece work, which was the norm in those days. I recently read the Hughie Hancox book about his time as a Triumph road tester. Back in the day every bike that came off the production line was road tested before dispatch. Interestingly it does not mentioned wether the cylinders heads were re-torqued as part of the pre dispatch routine. All the oils were removed which is why there were no visible leaks on new bikes (wash my mouth with soap and water) what am I saying! Same thing probably happened at BSA. I do know back then it was standard practice to select pistons to suit the bores on Ford engines, and most likely everywhere else. In fact I do believe that still goes on today.
-
Guys, I have followed this whole string on crankshaft end float with great interest as I posted a recent question on this subject.
What an incredible amount of information it contains and more importantly some very useful tips when I come to set the end float on my A7 in the very near future.
I can't help but wonder what it was like on the BSA production line in the 50's and 60's when these engines were being mass produced - surprised they
achieved such and good reputation and reliability especially winning the Mauds trophy as they could not have built them to the accuracy that we can with all the time in the world.
So thanks again for all the technical advice, I will put it to good use.
I am envisioning a fixture holding the case together with the crank in it and a loose inner race, dial indicator in place to measure play. Remove drive side of case and loose race, select and place appropriate shim set, then press final inner race with bearings home. Then, MAYBE, a second check.
Richard L.
-
Yes I'm sure they had simple in house solutions/jigs to assemble them quickly. I remember watching a video clip once of a BSA open day and the camera went into the factory. There was one old chap sat at a bench looking very calm puffing on his pipe selecting the best fitting components from a batch and with a couple of swift taps with his hammer they were as one. He'd performed that task many hundreds of times before - NEXT!!!
-
I can't help but wonder what it was like on the BSA production line in the 50's and 60's when these engines were being mass produced - surprised they
achieved such and good reputation and reliability especially winning the Mauds trophy as they could not have built them to the accuracy that we can with all the time in the world.
Yes, and the same reasoning applies to the rocker cover. You would not want to be on piece work, which was the norm in those days. I recently read the Hughie Hancox book about his time as a Triumph road tester. Back in the day every bike that came off the production line was road tested before dispatch. Interestingly it does not mentioned wether the cylinders heads were re-torqued as part of the pre dispatch routine. All the oils were removed which is why there were no visible leaks on new bikes (wash my mouth with soap and water) what am I saying! Same thing probably happened at BSA. I do know back then it was standard practice to select pistons to suit the bores on Ford engines, and most likely everywhere else. In fact I do believe that still goes on today.
If you have a close look at your engine you will find all sorts of funny marks stamped into the parts.
There were the "fit codes" as done by go- no-go Nancy thus "blueprint Bill" could select the correct out of spec part to fit the hole nicely.
Remember they were machined using high speed steel & high carbon steel tools traveling between stops so no 2 parts would ever have been identical by todays standards.
-
Well shes still ok running well. Stopped a few oil leaks that occured. Didn't get away with reusing the old gaskets *smiley4*
-
I can't help noticing on this site the recurring issue of the driveside main bearing moving on the shaft, with consequential damage to shims. The suggested peening of the shaft with a centre punch or the like in order to make the bearing inner race a press fit (as a previous owner had done to mine) falls into the butchery department. The idea of using loctite isn't much better. Seriously, the bearing should be a push (not press) fit, or a least a reasonable sliding one so, unless it's really loose, there won't be enough room for a film of loctite to do anything.
The same problem can occur on the single cylinder models, only they don't have shims to worry about. The whole matter boils down to how tight the nut is. I can only presume, therefore, that most people are not doing that nut tight enough. Are you using a spanner or some similar form of grip, or driving it tight with a punch? A punch and decent sized hammer is the only way to get that nut tight enough. I've been using that method on all my BSA's for over 50 years, and never had one come loose. And that includes some highly stressed engines running 13:1 compression.
-
I've been using my air powered rattle gun that I use with one of these: https://picclick.co.uk/BSA-Cush-Drive-tool-A7-A10-B31-New-322224770954.html
-
G'dat RD.
I agree. The tension on the nut is the key. Using an SRM nut or the pegged spanner on the original nut and the motor locked up 65ft/lb does the job. Yes before these I used the hammer and punch method, even on my race motors (14:1 methanol drinking A7SS).
Cheers
GB got in 1st. One of those for the plunger and SRM nut and socket for the Cafe.
-
I am doing well not been to pub today again, I use the old round nut hit it home with a punch{ I love the sound of metal on metal in the morning *bash*} and then put the locknut on which is lathe turned to fit inside the big round nut, {lovely job *work*} it has two recesses in it which also get smacked with a punch and hammer and bobs ya uncle. I've used this method since chewing shims ages ago after tightening it with 18 inch stillies and a bar. it managed to just come undone up to a washer and the split pin and then shim in sump *pull hair out*. alls good now *smile* might have to go for my medication friday *beer*
-
Years ago, before everything including the light switch self tapper had a torque reading, fitters had a feel for how tight a nut or bolt should be. Things were either loose, hand-tight, tight or 'very tight' and the crankshaft nut falls into the latter category. The trouble with torqueing the nut, is how do you lock the engine without causing damage? I note one person a while back suggested jamming a piston. I wouldn't recommend that, as the torque required could well crack or at least distort a piston, and possibly the conrod too. As for amount, I see Muskrat suggests 65ftlbs. If I were using a torque wrench, I'd double that.
-
HI RDfella.
That is the recommended torque figure for the Cush drive nut. How on earth are you going to lock the crank shaft to attain 320 ft. lbs. I think you will do more harm than good.
ELLIS
-
......... How on earth are you going to lock the crank shaft to attain 320 ft. lbs. ........
How do you get 320 from doubling 65?
A method of 'locking' the crank of my Plunger motor that I tried a couple of times with apparent success, but scepticism is to screw a bolt in the lower primary tensioner stud hole (Inner case holding screw on S/A's) so it stops against the web of the crank (one side for loosen, other for tighten)....took suspiciously little force but checked with two different T-wrenches.
This may have different results with other cranks than my L/J ....I'm open to opinion from anyone who gives it a go....
-
Doh, didn't have my maths head on *doh* 65+65=130ft lbs that's better.
ELLIS
-
Years ago, before everything including the light switch self tapper had a torque reading, fitters had a feel for how tight a nut or bolt should be. Things were either loose, hand-tight, tight or 'very tight' and the crankshaft nut falls into the latter category. The trouble with torqueing the nut, is how do you lock the engine without causing damage? I note one person a while back suggested jamming a piston. I wouldn't recommend that, as the torque required could well crack or at least distort a piston, and possibly the conrod too. As for amount, I see Muskrat suggests 65ftlbs. If I were using a torque wrench, I'd double that.
I believe the BSA manual says something like 'Do the cush drive nut up very tight'. No torque values quoted. Most home mechanics in the 1950's & 60's would have bunged a lump of wood against the sprocket to jamb the primary chain and used either a large Stilson wrench or a hammer and a drift.
-
G'day all.
65ft/lb isn't that tight. The flywheel nut on a VW is 240ft/lb!
Mostly I put the bike in gear and lock the rear brake. I have jammed the sprocket with timber if the wheel isn't on.
Cheers
-
Hi All,
The easiest and safest way (I find) to lock the crank and clutch/ gearbox shaft is with a clutch locking tool
two old plates bolted together and to a two foot handle
I have several sets of plates that suit different clutches that fit the same handle,
Today I added a further pair to suit a Pearson (Suzuki based) clutch on a 350 Goldie
I would think 130ft/lbs torque would break or bend something *warn* *warn* *pull hair out*
65ft/lbs and a drop of threadlock and I have never had a problem
John
-
In addition to my earlier reply;
Reply #89 on: Today at 04:59:30
I remembered that I think the S/A inner case bolts may be 5/16" whereas the Plunger Primary tensioner studs are 3/8" (casing end), and also there was mention in a different thread of one of the three front S/A outer case (5/16"?) screws may be able to serve the same function (locking the web if too long).
By my reckoning, this could be easily and safely researched by anyone with the barrels and outer Primary case off to have a visual on the progress .
-
On my Sportster they have a reputation for the engine sprocket coming loose, and this is retained by a large hex nut. First time had to pull that I found it so extraordinarily tight I had to make up a plate with pegs to lock the clutch, then with a socket and bar I had to slip a length of about 5 foot of scaffolding tube over it and apply myself to that. I’ve had the misfortune to have to go in there a few times over the years and always use, by feel, whatever that torque setting must produce – and I imagine it must be quite a big number. I also Loctite it each time.
Chubby bloke x 5 foot x raising a sweat = ???
-
RD fella what you say takes me back to when as a 13year old I put a cylinder head on a 2 stroke field bike and PING a long stud came flying up at me which had snapped off at the crank mouth. dad said I was too ham fisted or words to that effect{long time ago} anyway he got the remainder out and turned me another stud. over the years he taught me to -FEEL FOR IT, and I,ve very rarely used a torque wrench . only on straight 6 car engines, my mate was amazed how close I could get them pulled down to near the torque.
-
Hi All,
One of the best tool investments I have made in recent times is a (second hand) Snap On 18v battery impact wrench
It is fkn great at opening things like Cyclo's HD engine shaft nut (and retightening them too *smile*)
It works great on the clutch and the likes of flywheel extractors, the rattling of the impact just pops them off
It does not need full throttle on the switch to do this,
great care is needed when using it to do up small diameter nuts and so on
I learned the "feel" factor as a skinny kid, and only occasionally resort to the torque wrenches
John
-
In an effort to allay fears about applying excessive torque, I tried to find my list of bolt torques for given diameters / steels. Couldn't find it, but did come across the following:
If I recall correctly, the diameter of the thread concerned is 3/4" and the torque for a nut of that diameter (fine thread) varies (depending on the quality of the steel) between 101 ftlbs for grade 1 to 480 ftlbs for grade 8.
I seem to racall those mainshafts were EN32 case-hardened, which has a tensile strength of 71,000 lbs / sq.in. That would put the torque required in midrange, well over 130.
In conclusion, the words of Bruce Main-Smith (from his Gold Star book) may be relevant, as the singles have a similar mainshaft.
"The precaution is to keep the nut really tight. And the penalty for neglect can be disentregation of the mainshaft. It is more effective to jar the nut tight with a hammer and brass punch than to heave on a spanner".
-
In conclusion, the words of Bruce Main-Smith (from his Gold Star book) may be relevant, as the singles have a similar mainshaft.
"The precaution is to keep the nut really tight. And the penalty for neglect can be disentregation of the mainshaft. It is more effective to jar the nut tight with a hammer and brass punch than to heave on a spanner".
Or an impact wrench?
-
Not keen on impact wrenches unless the torque can be dialled in, otherwise the tightness achieved is anyone's guess. Mt pet hate is garages doing up wheel nuts with them. Seen wheel studs stripped this way and others sheared off. I gave up on 1/2" IW's. Current one is 1" drive and runs to 1,800 ftlbs. Better not use that on the A10!
-
pet hate is garages doing up wheel nuts with them
Can understand that but around here they do them up so far with he rattle gun then pull them up with a torque wrench, send you up and down the road a bit and torque them again.
-
pet hate is garages doing up wheel nuts with them
Can understand that but around here they do them up so far with he rattle gun then pull them up with a torque wrench, send you up and down the road a bit and torque them again.
If you watch the tyre jockeys they pull the torque wrench until it clicks...then give an extra yank. Great!
-
If you watch the tyre jockeys they pull the torque wrench until it clicks...then give an extra yank. Great!
Ha yes I have seen that but not on a wheel, well thing is - vote with your feet
-
Bill - they actually use a torque wrench?? Must be a Bentley franchise. When I spent five years in the garage trade I preferred a spider. All down to that 'feel' again.
But back to the crankshaft nut question - it needs to be TIGHT. With an impact wrench I'm never sure whether the nut / bolt I'm on is tight enough or too tight. So I only ever use them for undoing things - like the crank bolt on a car to get to a timing belt.
-
SRM recommend the cush drive nut should be torqued to 60-65ft lbs. I do think they know what they are doing. Add some Loctite for added security if you wish.
ELLIS
-
Well, as an engineer I care to disagree with them. 65lbs is the sort of figure you expect 10mm bolts to be torqued to these days. The BSA mainshaft thread is 3/4" dia, if I recall correctly. See my earlier post about figures for that size nut / bolt.
-
G'day RD, maaaate (spoken in Aussie accent).
In the old days torque wrenches were few and far between. Most mechanics used the 1, 2 or 3 GRUNT method or heavier hammers. Now days most hobby/home fiddlers have a torque wrench. Any literature I have/can find states 65ft/lb for that nut. If SRM agree I take it as gospel.
There's another old saying. "You can lead a horse to water but you can't make him drink".
For the last 20 years that I can remember all tyre shops down here use a torque wrench to tighten wheel nuts. Would be due to wheels falling off and litigation. The general rule is 80ft/lb, some manufacturers require more or less. Out on the road I use two grunts.
Just had to check my memory so looked up VW flywheel nut. Flywheel gland nut M28x1.5, 217ft/lb for 1500cc and less, 253ft/lb for 1600cc. One of my first jobs as a 1st year apprentice was rebuilding VW motors.
Cheers
-
Seems to me the spanner v hammer and punch debate falls into two camps. So I’d like to conclude my input with the following observations.
Firstly, the brevity of my comment about disagreeing with SRM may have seemed a little pompous. Those who know me will vouch that of my many vices, arrogance or pomposity do not feature. Maybe I was a bit short because I get irritated when people take the view that because a company is well-known or big, it is automatically right.
I have known the Ford motor company to be wrong when it advised a certain piston / liner pairing that were actually a mismatch. I could give many similar examples - no-one has a monopoly on wisdom. It happens I am an engineer, and I do disagree with a 65ftlb torqueing of the mainshaft nut but, having said that, I also appreciate there are people on this forum who know more than I. Here’s why I disagree with using a spanner:
1. Accepted wisdom from those who built them originally is that a hammer and punch is superior to a spanner. Why go against that advice?
2. When using a punch there is no need to lock the engine. With a spanner there is, but how? Remember, if restraining the shaft with the sprocket, the cush-drive cam will be forcing against the nut you are trying to tighten.
3. If using a spanner, what torque do you apply? We know that nut has to be TIGHT, so why choose a figure that is only around half that of the industry-recommended torque for a nut of that size?
Would be interesting to know whether those who are experiencing failures are using a spanner or a punch. I will continue using the latter, as in over fifty years of fettling BSA’s I’ve never had a mainshaft nut come loose.
-
Well I've found the method that works for me and I'll keep using it, which I needed to again today, and just to throw a spanner in the mix, the torque wrench I used (new acquisition clicky-ratchet one) is in Newton-metres/Kg/cm....everything except Lb-Ft/Ft-Lb...maybe even gallons *conf2*...I got it to ~110 N-M whatever with very little effort
each to their own.....
Hey Admins, brief (further) off topic (but will be wherever it goes), I noticed the other day the little thing over there --->> in the bottom right corner that seems turned out to be a kind of 'edit' button...is that new?
-
torque wrench I used (new acquisition clicky-ratchet one) is in Newton-metres/Kg/cm....everything except Lb-Ft/Ft-Lb...maybe even gallons *conf2*...I got it to ~110 N-M whatever with very little effort
65 lbft = 88.12 Nm. 110 Nm = 81.13 lbft.
Downloaded a converter app thingy to my phone. Comes in quite handy sometimes *smile*
-
Quote from: duTch on August 19, 2018, 22:36:01
torque wrench I used (new acquisition clicky-ratchet one) is in Newton-metres/Kg/cm....everything except Lb-Ft/Ft-Lb...maybe even gallons *conf2*...I got it to ~110 N-M whatever with very little effort
65 lbft = 88.12 Nm. 110 Nm = 81.13 lbft.
Downloaded a converter app thingy to my phone. Comes in quite handy sometimes *smile*
Yo thanks, Haynes graciously put one in my Hilux manual, and I used the conversion factor last time to 80-something (the setting on the handle is a bit vague), but just did it to a bit more to test the wench... *whistle*
Probably should split this off into a talk wench torque ... *bright idea*....?
-
Can't remember where this came from. I think it was in the box my torque wrench came in.
Col
-
Spose I should explain. There are 9 columns. Each three columns are a conversion from one to another, starting with a round number. The first 3 columns convert from ft-lbs, the next 3 from Newton-metres, the last 3 from Kilogram-metres.
Clear as mud.??
Col
-
Well, If you've bought an SRM cush nut, I would definitely recommend against using a hammer and drift. Then, if you've bought an SRM timing disk, you might have some trouble using it with a standard cush nut, If you are following BSA Service Sheet #208, you will be using a C-spanner to tighten your cush nut "as securely as possible" (maybe 65 ft-lb?). If that C-spanner is, say, 9" long, tell our arm to press with about 87 lb. force. (I don't think they considered Archimedes and cheater leverage bars when saying "as securely as possible.")
Richard L.
-
Hey Admins, brief (further) off topic (but will be wherever it goes), I noticed the other day the little thing over there --->> in the bottom right corner that seems turned out to be a kind of 'edit' button...is that new?
Where? Can you take a screen grab?
-
Quote from: duTch on August 19, 2018, 22:36:01
Hey Admins, brief (further) off topic (but will be wherever it goes), I noticed the other day the little thing over there --->> in the bottom right corner that seems turned out to be a kind of 'edit' button...is that new?
Where? Can you take a screen grab?
-
Oh yes, I just tried it one of my posts. It went into Modify mode, just like clicking on the word 'Modify' ;)
-
Oh yes, I just tried it one of my posts. It went into Modify mode, just like clicking on the word 'Modify' ;)
...except it didn't support adding pics.... *dunno2*
-
Oh yes, I just tried it one of my posts. It went into Modify mode, just like clicking on the word 'Modify' ;)
...except it didn't support adding pics.... *dunno2*
Oh yes, I didn't notice that!
-
Almost shy to ask a shim question here, having read so much on it, written so much on it, and been given so much good advice. Nonetheless, I don't recall this question being asked by me or anyone else, and if it has, there is too much info to sift through to find it.
Question is: Should we target an allowance for the minimum amount of side play before installing shims? I want to tell my machinist to dress the face of the new T.S. bushing so the crank is not locked up when the cases are assembled. I don't think it would be good if the play (without shims) was, say, 0.004". That would mean the shim (or shim stack) might be just 2-3 thou thick. Arguments for specially machined thick shims seem to support the notion that such a thin shim, by itself, is a recipe for shim destruction. ("Well, Richard, if you get your bearing on right, tight to the web and with the shim sandwiched between and (maybe) Loctited, the shim should be fine, you dummy." Then I say, "Well, yes it should, so why bother with custom-made thick shims?")
Going back to my original question in the recent rebirth of this topic.
I've removed the old two-piece bushing to find that its flange is 0.011" thicker than my new solid phosphor bronze bushing. So, asking if the machinist can skim the bush to create minimum side play seems a moot point.
Richard L.
Any thoughts?
Richard L.
-
G'day Richard.
That's a good example of why shimming needs to be done. With after market parts coming from all parts of the globe there's bound to be differences.
If the old one was thicker in the thrust flange tan std I wonder what the PO did to the cases or crank to make it fit (grind thrust face of crank, counter bore the case etc).
Looks like it's back to shims for you.
Cheers
-
Well, I'd planned on shimming anyway. Thrust face of crank and landing at case look unmolested
Richard L.
-
What a great forum, and well like a kid in a candy store etc...so much amazing stuff to digest.
I know this thread is old but thgt it would be interesting to hear thghts on the shim issue. I hate those darn shims...When they break up that glass hard stuff will destroy an engine in a second.
I shimmed with said shims to get the end float, got it all measured up, removed them and then turned up a single solid shim to size from some tough tool steel which I played with the heat treatment then loctited in place. Just seems less likely to break up so to speak.
Time will tell I guess.
-
Nothing to do with shims but a story from when I was young and a lot fitter than I am now. A few of us travelled up to the lake district many moons ago and one of the lads was on an A10 plunger which started knocking like crazy. We took the engine out in a car park and we took the head barrels and rocker box off in one piece. Nothing unusual the left hand big end had gone. After getting a new set of shells we bolted it back together we debated whether or not we would need to rest the tappets. Common sense won out (for a change) and we took the rocker box covers off and only one of the tappets needed adjusting and that was only by a few thou. The bike made it back to London and ran around for a few months before it started knocking again and he could then get the crank ground etc. etc.
It always strikes me as quite bizarre that nowadays with a hell of a lot more money and a hell of a lot more mechanical knowledge that our bikes need so much cossetting and care compared to those days when with 3 spanners, a screwdriver and a lot of luck they used to take a dreadful thrashing and still survive. I still have the A10 I started with 47 years ago and I distinctly remember throwing the crank shims away the first time I stripped it because I did not think they were that important. We just never had the money or the knowledge to do anything else but bodge them up but I swear my bikes give me more trouble nowadays and I do just about everything right *sad2*
-
Nothing to do with shims but a story from when I was young and a lot fitter than I am now. A few of us travelled up to the lake district many moons ago and one of the lads was on an A10 plunger which started knocking like crazy. We took the engine out in a car park and we took the head barrels and rocker box off in one piece. Nothing unusual the left hand big end had gone. After getting a new set of shells we bolted it back together we debated whether or not we would need to rest the tappets. Common sense won out (for a change) and we took the rocker box covers off and only one of the tappets needed adjusting and that was only by a few thou. The bike made it back to London and ran around for a few months before it started knocking again and he could then get the crank ground etc. etc.
It always strikes me as quite bizarre that nowadays with a hell of a lot more money and a hell of a lot more mechanical knowledge that our bikes need so much cossetting and care compared to those days when with 3 spanners, a screwdriver and a lot of luck they used to take a dreadful thrashing and still survive. I still have the A10 I started with 47 years ago and I distinctly remember throwing the crank shims away the first time I stripped it because I did not think they were that important. We just never had the money or the knowledge to do anything else but bodge them up but I swear my bikes give me more trouble nowadays and I do just about everything right *sad2*
Great story, similiar to my dads AJ which someone fixed roadside.
I think the problem is that we are so used to "silent" japanese stuff that these old bikes now sound like they are literally falling apart so we keep fettling them.
Back in the day at least everything was less worn so to speak. Some parts of the engines today cant be fixed and are almost hanging on for dear life. Take the cam follower tubes for instance..there is almost no-way they can be fixed if worn and new followers ain't gonna fix it. Im sure the clatter you hear from the A series bikes comes from from those tubes which need to be a very tight sliding fit...Same with the rocker gear its all worn now so contributes to the mayhem and cannot be repaired. Just my 0.2$