The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: BSA500 on 22.05. 2018 12:45

Title: Crankshaft shimming
Post by: BSA500 on 22.05. 2018 12:45
Well here go again. Audible clunk when the cranks moved in and out. Cush nut fully kin tight 65ftlb. no other work done so timing bush ok no up and down play. The reason why I don't know but there will be careful checks. Oh no shim break up either. My question other than why  *pull hair out*. Can you reduce the clearance to around zero without issues. There is plenty of side movement on the pistons/conrods is it necessary to have some allowance??
Title: Re: Crankshaft shimming
Post by: duTch on 22.05. 2018 13:18

 Have you measured it? It can produce quite a clunk with very little movement (less movement than you'd expeect), but I'll let the others talk you through the rest....
Title: Re: Crankshaft shimming
Post by: BSA500 on 22.05. 2018 13:49
I have to much experience with this issue(don't ask).This movement is too much and the vibration  is horrible. I can also try to sort out an annoying tapping/clattering.
Title: Re: Crankshaft shimming
Post by: berger on 22.05. 2018 14:35
I flooded mine on sunday and when it did the odd fire I heard this horrible clunk noise too, its not long ago that I built her up. theres nothing on the sump plate regards shims like there was a few years ago but I do intend to investigate end float when changing the gearbox in the near future, I do know the metal on metal sound is a horror to hear you have my best wishes on finding a cure or reason for this and I hope I get an answer regarding my CLUNK , ime hopeing its not end float because a got that to about 1 and half thou.
Title: Re: Crankshaft shimming
Post by: muskrat on 22.05. 2018 21:20
G'day BSA500.
I agree with duTch, measure the endfloat first before pulling it down. If it's under 5 thou" I'd just monitor it.
Was the bearing a tight fit on the crank and the outer a shrink fit in the case? How much shim did you use?
Cheers
Title: Re: Crankshaft shimming
Post by: BSA500 on 22.05. 2018 22:01
The bearing is fitted using loctite 641 and I have bent bearings in The past trying to shift them. The trick is to dissolve the loctite using acetone.
Cannot remember what shim pack I used but the noise vibration is horrible so it's coming  down I shall measure the float before.
Title: Re: Crankshaft shimming
Post by: BSA500 on 24.05. 2018 11:13
Had an idea on How to make the shimming quicker and hopefully a little more accurate.
Take the crank out and clamp into a vice carefully. Remove shims bearing etc. Slide the bearing on- not all the way and then assemble the shock absorbed sleeve sprocket and tighten fully. Measure the gap shim and put back into the crankcase and a final check with a dial gauge. Any pit falls and has everyone else been doing this for years
Title: Re: Crankshaft shimming
Post by: muskrat on 24.05. 2018 20:30
NNNOOOOOO.
It all depends on where the outer race sits in the case and any wear on the thrust face of the timing side bush.
The end float of the crank is between the bush on one side and the bearing rollers against the outer race lip on the other side.
It's a PITA job but it must be done the way it's always been done.
Nice try though.
Cheers
Title: Re: Crankshaft shimming
Post by: Peter Gee on 24.05. 2018 20:41
Dear Muskrat, since I will soon be doing this job, what exactly in detail is the PITA method?

I do have the original crankshaft shim pack out of my unopened A7SS ( until I opened it) and a new one. Shall I just assemble up a new shim pack to the old dimensions?

I will also be using the same Steel backed TS bush that also came out of the bike, but with a new SAE220 insert.

A
Title: Re: Crankshaft shimming
Post by: muskrat on 24.05. 2018 21:10
G'day Peter.
1st if the T/S bush has been removed from the case may as well drop it in the bin. It wont go back in EXACTLY as it was and will need to be line bored again making it too big for the crank.
Once the bush is in and line bored/reamed to suit the crank. Put the drive side bearing outer in the case (heat the case and freeze the race) and the inner on the crank (I soak mine in boiling water for a few minutes and it drops on all the way). Now assemble the cases together (torque all the bolts) and fit all the cush components and torque the cush nut (65ft/lb). Now measure the end float with a dial gauge. This measurement less 1 thou" is the shim size needed (may need more than one shim but don't use more than three, get thicker ones). Now it all comes apart again to install the shims behind the inner race. Removing the inner race can be difficult, I first pour boiling water over it. If that don't work I pop the rollers out of the cage and use a bearing spliter type puller to remove it.
Once the shims are in place and inner race back on assemble again to recheck the end float. Sometimes it may need to be done more than once.
Cheers
Title: Re: Crankshaft shimming
Post by: Peter Gee on 25.05. 2018 06:31
Dear Muskrat,

No problem on the first matter. I am using my OEM TS steel cage to have turned and pegged new insert made for it- it won't be lead bronze ( cant get it) by lead phosphor SAE660 and of course it will be line reamed. I have enough materiel in SAE 600 to actually to turn a whole one piece bush if I so decide..

For your second advice I do have a dial gauge and I have a wide selection of shims and shim stock too. Your description has been very helpful as to the exact figure I need and some tips to manage it. Luckily my inner DS bearing is not too stubborn and it toois original and in VGC,  will not replace it...my bike will not be doing long mileages, mostly weekend  small runs.. Cheers
Title: Re: Crankshaft shimming
Post by: Greybeard on 25.05. 2018 09:23
Musky, please explain why the engine shock absorber needs to be fitted. I did not fit mine when I reassembled my engine last time.
Title: Re: Crankshaft shimming
Post by: muskrat on 25.05. 2018 10:27
Your right GB, the spring and sprocket can be left off, as long as it's all locked up snizentite.  ::hh::
Now get back out in the shed and clean all those parts and polish the rods. You want it all ready for when parts arrive  *lol*
Cheers
Title: Re: Crankshaft shimming
Post by: Greybeard on 25.05. 2018 11:51
OK you've still left me wondering. Are you saying the shock absorber nut needs to be done up?
Title: Re: Crankshaft shimming
Post by: muskrat on 25.05. 2018 12:14
Yes, eliminates the possibility of the inner race moving on the shaft. I know if it's tight on the shaft it shouldn't but!
Just to be on the safe side I like to have it as though the motor is running.
Cheers
Title: Re: Crankshaft shimming
Post by: Greybeard on 25.05. 2018 12:56
Yes, eliminates the possibility of the inner race moving on the shaft. I know if it's tight on the shaft it shouldn't but!
Just to be on the safe side I like to have it as though the motor is running.
Cheers
Ah, OK, I get it!
Title: Re: Crankshaft shimming
Post by: BSA500 on 25.05. 2018 12:59
So do I now  *smile*
Title: Re: Crankshaft shimming
Post by: BSA500 on 29.05. 2018 12:45
So did more stripping down. Endfloat is 5 thou not massive but enough for me. Biggest issue and source of noise/vibration is the really floppy timing side big end. When I rebuilt it there was some play but I was impatient to get riding. Big mistake it seems
Title: Re: Crankshaft shimming
Post by: BSA500 on 31.05. 2018 13:31
OK anyone who has seen the video sort of pulls a face similar to 'how didn't that go bang'. I have contacted a engineer who is going to check then most probably grind the journals(with the correct radius everyone). If we are talking about price £27.50 per side.
 I can then reshim rocker arm play and clean up bits ready. Also clean and check the anti syphon valve ball etc.
Title: Re: Crankshaft shimming
Post by: BSA500 on 05.06. 2018 13:07
The engineer now has the crank for a grind and it looks like I have to make the grub screw for the anti syphon valve(67-1401) as nobody stocks them. In the wet sumping thread you will see I had left this part out and had been wet sumping for some strange reason *problem*
Title: Re: Crankshaft shimming
Post by: Greybeard on 05.06. 2018 13:28
...looks like I have to make the grub screw for the anti syphon valve(67-1401) as nobody stocks them. In the wet sumping thread you will see I had left this part out and had been wet sumping for some strange reason *problem*
It's the same Whitworth thread as the cylinder block studs.
Title: Re: Crankshaft shimming
Post by: BSA500 on 05.06. 2018 13:50
Yep but I had better use a bolt as I would have to but one of those as well *grins* *grins*
Title: Re: Crankshaft shimming
Post by: orabanda on 05.06. 2018 14:05
I modify the retaining screw for the anti-sumping ball valve. From memory, the thread is 3/8 BSW.

To slightly increase the  spring loading on the ball I make the screw a little bit longer; think it was about 0.080". I also machine a little recess in the centre (create a shoulder) which the spring locates in centralises it under the ball).

Richard
Title: Re: Crankshaft shimming
Post by: muskrat on 05.06. 2018 15:14
Hay GB, you been using the Delorean again. The quote in your last post says 1974!!!!!
Cheers
Title: Re: Crankshaft shimming
Post by: Greybeard on 05.06. 2018 20:25
Hay GB, you been using the Delorean again. The quote in your last post says 1974!!!!!
Cheers
I guess I cocked up!
Title: Re: Crankshaft shimming
Post by: duTch on 05.06. 2018 23:29
 
Quote
Hay GB, you been using the Delorean again. The quote in your last post says 1974!!!!!  Cheers   

 Saw that and thought my eyes had totally cocked out.. *eek*. Remember,remember the 4th (or 5th) of November......

 
Quote
Quote from: BSA500 on November 05, 1974, 04:00:44

    ...looks like I have to make the grub screw for the anti syphon valve(67-1401) as nobody stocks them. In the wet sumping thread you will see I had left this part out and had been wet sumping for some strange reason *problem*

It's the same Whitworth thread as the cylinder block studs.

 I bought a spare plug & A65 spring from SRM, but was a couple of years ago....measured it at 16 T.P.I (3/8 ww), x 0.1735 long which is a nothing measurement between 11/64" & 3/16"

 **...sorry 'Off Topic'.... I've had an issue with my now 4yr old Macbook  where it saves files/pics on the 12/12 of whichever year I'm in- been onto Apple and spent a few hours on the phone doing 'screen-sharing' to sort it but no go. Is not a major issue until I had to prove I tried to pay my rego one day and couldn't get a connection-several times ..... *conf*
 Normal Programming will now resume......

 Pics;
 
Title: Re: Crankshaft shimming
Post by: BSA500 on 09.06. 2018 18:19
Crank grind done. One journal was 3 thou under the other. Could explain a lot
Title: Re: Crankshaft shimming
Post by: BSA500 on 13.06. 2018 12:56
Why is it whenever I need big end shells that size has become the rarest of the rare size. I need -30 I know Draganfly have them but they would at £72 plus post. Also SRM do but again £54 plus post. *sad2*
Title: Re: Crankshaft shimming
Post by: RichardL on 13.06. 2018 13:07
More and more we are in the bullet-biting business when it comes to paying for the parts we need. Oddly, or unfortunately, or naturally, the prices go up because of our own friends and members here. I have pondered the question as to if parts scarcity is, in part, due to the forum making it much easier and welcoming to restore our marques. We HAVE grown a bit since 2006.

Richard L.
Title: Re: Crankshaft shimming
Post by: BSA500 on 13.06. 2018 13:22
I know what you mean,but the prices for these are quite reasonable from other trusted suppliers at around £30 but no stock. I had exactly the same problem years ago when I needed -20. Alot of the new shells are unbranded as well so some risk there.
Title: Re: Crankshaft shimming
Post by: chaterlea25 on 13.06. 2018 21:43
Hi All
Quote
I know what you mean,but the prices for these are quite reasonable from other trusted suppliers at around £30 but no stock. I had exactly the same problem years ago when I needed -20. A lot of the new shells are unbranded as well so some risk there.

Following on from my reply to GB about the quality of parts
Big end shells are something where quality branded parts are essential

If a maker will not put their name on the packaging its not worth  buying

John
Title: Re: Crankshaft shimming
Post by: BSA500 on 16.06. 2018 15:30
Got the crank back from grinding looks good
Title: Re: Crankshaft shimming
Post by: BSA500 on 22.06. 2018 12:51
Okay took two days but I have the crank shimmed at 1 thou. Tightening the sleeve against the bearing did the trick. I had bolted it up and the crank locked, did up the sleeve and voila 1 thou. There was alot more to it than that but yay it is done and the reground crank is spot on as well  *smile*
Title: Re: Crankshaft shimming
Post by: berger on 28.06. 2018 12:37
i have not been to the pub, but will be because I can ;) well what can I say, my clunk now seems to have been the miss matched engine sprocket and sleeve. even tho they both could ride with each other they were not a good match. since ragging the crank about when changing the box and getting nothing more than the one and a half { mines a pint} thou it was set at it doesn't clunk anymore after fitting really good matching sprocket and sleeve. result! i'm going to have a gallon and celebrate BSA making several different set ups of these parts for owners to get confused with when other people have messed over the years *beer* KERLUNK!!!!
Title: Re: Crankshaft shimming
Post by: Wayno on 04.07. 2018 19:50
Hi Muskrat, I need to gate crash this discussion as I will be doing this job very soon.
I’ve read your instructions to check/set the crankshaft end float several times with great interest as I’ve never had this explained to me before.
I just about understand it (you’ll be pleased to hear) but I can’t quite work out where the end-float actually is!!
Are we adjusting the end-float of the main bearing?  I ask this as I think when we assemble the crank inside the casings and tightening the cush-drive nut up fully, it will put a side load on the bearing and take up any free play.  This will presumably pull the crank shaft away from the timing side bush and tight into the main bearing.
I have included a couple of photo’s showing both sides of my LH casing, the bearing outer race still fitted and with the large bearing shim (67-349) in place and free to rotate.
Presumably when everything is tightened up the large bearing shim (67-349) is trapped tight between the inner race of the bearing on the inside and the boss of the cush drive bearing (67-2053) on the outside and rotates in the LH casing with the crankshaft?
I hope you can resolve my confusion on this.
 
Title: Re: Crankshaft shimming
Post by: Greybeard on 04.07. 2018 20:12
The arrangement locks the crankshaft to the drive side main bearing inner race so any expansion or float will be in the timing side bush. As the timing side bush supplies oil to the crank it needs to be pretty closely fitted, hence the crankshaft should have minimal endfloat. I believe this to be true but am willing to be told different.
Title: Re: Crankshaft shimming
Post by: muskrat on 04.07. 2018 20:53
G'day Wayno.
With the inner race on the crank and all the cush/drive components done up it can slide back and forth in the outer race (the rollers are only trapped by the outer race on the outside). So once you put the other case on there is movement between the thrust face of the bush and the rollers against the lip in the outer race. Shimming between the inner race and the crank reduces this movement. Do NOT shim between the outer race and case as there is no mechanical clamping them in place other than the interference fit of the outer race in the case.
See clear as mud!
Cheers
Title: Re: Crankshaft shimming
Post by: Wayno on 05.07. 2018 09:31
I woke up with one of those EUREKA moments.  Of course, when its all nipped up the only free play can be between the crank and the bush. DOH!!
I knew where I had to get just couldn't visualise it.  Must be all the sweat running in my eyes. 
My old bearing must be similar to yours as I can pop the rollers out and get at the inner race to use a puller.  The nice new bearing I received from DRAGANFLY yesterday (make QCB) looks great but can't pop the rollers out so cant separate inner race to remove it to add shims.  I fear once its on - its ON!!  I will have to return it. Do you know the make of bearings that you can pop the rollers out?
Very last question - is the crank end float 0.001" on all A7/A10 twins do you know?

Thanks for the help.
Title: Re: Crankshaft shimming
Post by: muskrat on 05.07. 2018 10:09
G'day Wayno.
If your real careful a bearing separator type puller can work on the rollers. Set it all up and add a little pressure then pour boiling water over the bearing.
Cheers
Title: Re: Crankshaft shimming
Post by: Greybeard on 05.07. 2018 10:13
The arrangement locks the crankshaft to the drive side main bearing inner race so any expansion or float will be in the timing side bush. As the timing side bush supplies oil to the crank it needs to be pretty closely fitted, hence the crankshaft should have minimal endfloat. I believe this to be true but am willing to be told different.

G'day Wayno.
With the inner race on the crank and all the cush/drive components done up it can slide back and forth in the outer race (the rollers are only trapped by the outer race on the outside). So once you put the other case on there is movement between the thrust face of the bush and the rollers against the lip in the outer race. Shimming between the inner race and the crank reduces this movement. Do NOT shim between the outer race and case as there is no mechanical clamping them in place other than the interference fit of the outer race in the case.
See clear as mud!
Cheers


See, I talk a load of bollocks sometimes! I forgot that the drive side bearing has rollers. Lucky someone here knows what they are on about!
Title: Re: Crankshaft shimming
Post by: duTch on 05.07. 2018 10:20

 I'm a slower typerator than Musko and BG...they both got in on me..

 Posted by: Wayno
 
Quote
"....Of course, when its all nipped up the only free play can be between the crank and the bush. DOH!...."

 On that side, but on the other side.....the rollers against the lip, as ;

  Posted by: muskrat;
 
Quote
"....So once you put the other case on there is movement between the thrust face of the bush and the rollers against the lip in the outer race....."



 Wayno, what engine is yours ?

  I'm asking because that bit that shows in the picture looks like a Plunger engine part that I think later engines don't use- I had one in mine when I first bought it and always thought it was a oil-slinger type thing because the early Plungers to '54 had no seal, but I put one in (with LJ crank) and the 'Slinger' is now lost in history....


Title: Re: Crankshaft shimming
Post by: Wayno on 05.07. 2018 10:40
Dutch,
She is a plunger a very early short stroke A7.  Built Sep 1950 (before I was even a glint) Eng. No. ZA7-603.

I would guess it is an oil slinger too as it is clamped between the inner race of the bearing and the boss of the cush drive.
Guess it now spins at crankshaft speed and flings!!  Would this be to stop engine oil sneaking into the chain case?
Title: Re: Crankshaft shimming
Post by: duTch on 05.07. 2018 11:45

 
Quote
..... Would this be to stop engine oil sneaking into the chain case?......

 Yup- that's fairly much the way I see it...

 Mine is a BA10 with stamps 23.12.52, so Ive always called it a '52, and that's how it's rego'd, but now I know it's a '53 engine in I reckon a ~'56 frame
Title: Re: Crankshaft shimming
Post by: muskrat on 05.07. 2018 20:53
G'day Wayno.
ZA7 AFAIK was the last of the long strokes. My A7 plunger is AA7 and the 53rd one off the line.  *dunno*
Cheers
Title: Re: Crankshaft shimming
Post by: chaterlea25 on 05.07. 2018 21:08
Hi All

Googling QCB bearings as I had never heard of the brand brings me to,

https://nbcgroup.co.uk/products/bearings/cylindrical-roller-bearings

I wonder   *conf2   **????* *????* *????* *????*

John

Title: Re: Crankshaft shimming
Post by: Wayno on 07.07. 2018 13:18
Yes, they are the ones as supplied by Draganfly.  They do look very sturdy and well made. I'm now looking into acquiring a bearing separator to fit around the rollers (as suggested by muskrat) so I can remove the inner race without damaging it and adjust the end float.
I suppose one idea to avoid removing the race too many times is to temporarily place the shims between the crank and the bush (if that's possible) just to achieve the 0.001 - 0.003 thou end float then remove the inner race once and place the shims in their correct position.
Any comments on that thought guys?
Title: Re: Crankshaft shimming
Post by: muskrat on 07.07. 2018 15:14
G'day Wayno.
Theoretically that would work BUT! Every time the outer race is inserted and removed from the case the crush on the race may diminish. The race is a C3 fit meaning it needs a certain amount of crush to bring it to the right dimensions (roller clearance). First you would need to assemble without shims and measure the end float to work out the shims needed. Then remove the race and put the shims in and assemble to check the end float. Then pull it all apart again to put the shims where their supposed to be behind the inner race. Seems like a lot of unnecessary work and risking the outer race fit in the case. 
The correct way (mine anyway) to remove the outer race is to heat the case to about 200C, the race usually falls out. To insert heat the case and freeze the race. It will drop straight in.
With the shims where their supposed to be (behind the inner race) and the cush nut is done up to 65 ft/lb they are trapped and can't move. If its set up with one or two thou" end float and the shims are behind the outer race there is a possibility the outer race can move that amount and the shims are loose.
Just do it the right way and we won't have to get the trailer to rescue you! LOL.
Cheers
Edit: Some people have an inner race with a honed bore that slips on the shaft easily to take the end float measurement. Then replace with the new race. I don't subscribe to that method as there may be small differences in the race/roller dimensions, but it works for them.
Double edit: DOH, just re read your last post re shims on the other side. That could work.
Title: Re: Crankshaft shimming
Post by: duTch on 07.07. 2018 16:49
 
Quote
......I suppose one idea to avoid removing the race too many times is to temporarily place the shims between the crank and the bush (if that's possible) just to achieve the 0.001 - 0.003 thou end float then remove the inner race once and place the shims in their correct position.
Any comments on that thought guys? 

 I'm not sure what Musko is on  *whistle* or if I just read it wrong, but Wayno if you mean between the sprocket bush and crank, it won't achieve anything, as it's just packing the bush out and they still move together... *spider*...- or if you mean the T/S Main bush, it's a bigger diameter so also fairly unlikely to work.... *conf2*
Title: Re: Crankshaft shimming
Post by: Wayno on 08.07. 2018 10:51
Gents-  I think the heat is affecting what few brain cells I have!!  I did mean to temporarily put the shims between the crank and the T/S bush but of course dutch you are quite right the dia is bigger so no go.  I have removed the old inner race using muskrats method of boiling water and I was stunned when it came off so easily leaving plenty of water for a well need cuppa :)
Armed with that knowledge, it should be straight forward to slip the new one on/off to adjust shims as you recommend.
Thank you all again for your experience.  Now need to sort crank either find a better one or risk grinding further.
Cheers all