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#843077 03/16/21 3:19 am
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A65 crankshaft bush is line reamed and almost ready for assembly. I say almost because it is just, I mean just, a hair snug when everything's bolted together. As in - when it's assembled to check end float, in my very cold unheated garage, the crank is locked down and won't rotate. -when I take the whole assembly inside the house, after it's sat for a couple hours warming up the crank will rotate. Although still not spin ez.
So my question is.
Instead of having the whole damn thing setup for inline reaming again, with so little that needs to come off, would it be advisable to use a quality cylinder hone (not ball hone) to take off that tiny bit from the bush?
Other ideas??
Thanks!

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And how long was the crank in the very cold garage for before it was fitted?

I ask because a few years ago I built up a motor for a friend. I actually didn’t need to regains anything. The Bush measure fine and round. The crank measure round at 8 points (all the points I checked at) but measured under size. I took the crank and the micrometer into the house and it was well over a day before the crank had finished growing back to size.

So, my point here, leave the assembly a few days in the garage before doing anything with it, force some oil through the gallery also.

Or leave the assembly in The house for a few days and wait until everything has finished growing. Also, force some oil through the gallery.

(I’d be more inclined to do the latter)

If it’s still too tight, give it back to your machinist. I wouldn’t pay out all that money for a TS Bush job only to bugger it up with available tools at home.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
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I would leave the timing side bush alone and from your description it sounds like the crank is locking up because its too wide for the case.

This can happen for a variety of reasons such as the drive side bearing not being seated fully in the case, too many shims being fitted on the drive side and perhaps the new timing side bush has a thicker inner lip or bronze washer.

You don't mention whether the crank is original to the cases, I believe that some later cranks were slightly wider and will cause this issue and need slight machining.

Also are you using a ball or roller bearing on the drive side? The roller type uses a shim cup with a set of shims to control end float, the ball type doesn't use shims and requires the alternator rotor and nut to be fitted to pull the crank fully onto the bearing.

Hopefully others with more knowledge will chime in with their thoughts.


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Does it spin OK if assembled without end float shims?
May be you have zero endfloat? You may need a thou or two less shim.
If thats OK it is customary to give a fresh assembled crank/ cases an axial clonk with a soft faced mallet, this can help seat bearings and quite often frees off the assembly. If that doesnt work, its strip check / measure to find the bind.


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When fitted up the cases were next to my garage heater, so warm. The crank wasn't however, when initially assembled like that it spun ok. Well enough that if that's how it was all the time I'd leave it. After the whole thing sitting in my unheated garage overnight it locked down so it just would not spin. After bringing it inside for several hours it would BARELY spin with effort.basically the cases had warmed up enough to let go a little but the crank was still chilly.

It is the original crank/cases.
64 so still running ball bearing.
couldn't check end float cause too tight to move. Had bearing shim cup installed between ball bearing and crank but no shims inserted.
Bearing was seated correctly within the case.
Bringing back to machinist isn't an option. I will have to source someone else to do it if it requires re-setup re-machining.
I'm wondering if hitting it with a three blade brake cylinder hone would do the job.
-or ruin it...
Thanks

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I would NOT run a brake hone through the bushing, you are introducing grit that will become imbedded in the surface and there is no way to keep from taking off more from one side than the other.

can you describe how you reamed the bush?


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Find the tight spot in the bushing and "massage" it


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It sounds as though you have an end float problem.
So why are you considering changing the bore of the bush?
Not trying to be critical--just trying to help identify the real problem---if you dont do that then solutions are just flailing around in the dark.
HTH

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It seems at this moment that you cannot determine whether the issue is due to insufficient end float clearance or an overly tight fit between journal and bush.
I wouldn’t mess with the bush until you are sure that it is the problem.
Perhaps you could heat up the cases using hot air guns/hairdryers. This will take patience over maybe an hour or more, until the crank is free to rotate again.
Then you will be able to check for end float (this assumes that the driveside journal slips fairly easily within the bearing inner).

The radial clearance of the bush/journal will only change by small fractions of a thou under the modest temperature differences that the crank and cases have experienced.
If those temperature differences cause a problem to this interface, then the bush is either reamed too small, is not accurately line reamed or the cases are assembled slightly “stepped”.

On the other hand, the axial clearance of the crank increases considerably as the cases are heated.

As I mentioned, if the driveside journal is a tight fit in the ball bearing, you won’t be able to judge the end-float of the crank anyway. Not being a BSA chap, I wonder if a lipped roller bearing may make this easier?

Another thing that can cause the tightening is using a driveside bearing with too small an internal clearance, I only mention it as a last-ditch possibility.

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As Gunner mentioned, the ball bearing does not use the shim cup, so you are probably locking up the crank because of that. If it is the bearing you should be able to see a shiny spot where it is interfering.

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I hear what people are saying about the ball bearing/shim cup thing. I'm going to remove the shim retaining cup from the assembly and see how it feels after that.
I am curious though what/where people are getting that information. I have the 63-65 parts book that references the ball bearing (67-1240) and also shows a retaining cup (68-0186) as well as the three different options for shims.
Or course real practical knowledge is way more helpful than trying to build something just from a book but I'm just wanting to make sure I'm not missing or skipping something.
Anyways, thank you all so far. I will have many more questions I'm sure and appreciate the feedback!!!

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By the way have the same problem with a bush being too tight in one place, so I assumed it's not in line with a ball bearing. Thought about scrubbing a tight spot CBS way but seriously afraid the clearance will be too big for a proper oil pressure. Took the block to the machinist again to install original type of a bush ( steel with bronze insert pegged together ). However until now it is not done yet. I was looking for possible tools to do a line boring and found a film about a Harley pinion cutter:
https://www.facebook.com/charley.dawidson.9/videos/1118128241966317
This tool is shown in 1.30 min and looks like could help with fine honing of the bush.

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Just highlights the fact that there are so many directions these things can expand and contract
in as they heat up and cool down. All the talk about machining to 1/10 thou is crap really.
If you have a couple of thou endfloat, bolt the thing together and bolt the barrel on, then try it.
If you've used a material like leaded bronze for the bush it'll stand being a bit tight. If you've used
PB1 or similar you'll have to scrape the bearing. Remember they heat up pretty quickly when
started, so it's not a huge problem really.

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If you are worried about clearance, get a bore gauge and measure the bushing

If you have the proper clearance, it is possible you have a slight misalignment

That is why I stated to find the high-spot in the bushing and address that specific area instead of taking out the bushing and starting over

What you could do, when the cases are bolted together and the crank is installed, is heat the bushing / case up

If the tight spot goes away once heat is applied to the case then you know you have either a lack of clearance or misalignment

Apply sharpy to the crank journal and inspect, check for any rubbing or witness marks

Once you find the proper area, remove material from the bushing, could be a few tenths causing the issue!

Cheers


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Quote
I am curious though what/where people are getting that information. I have the 63-65 parts book that references the ball bearing (67-1240) and also shows a retaining cup (68-0186) as well as the three different options for shims.


I think you are right, I had a look through the parts books for all the years and the shim cup has always been there regardless of whether a ball or roller drive side bearing is fitted.

However I did note that on the timing side the bronze thrust washer is only fitted on engines using the roller drive side bearing.

I think the idea was that when the drive side ball bearing is used the crank is locked into place by the alternator. When the roller bearing is used the crank isn't locked and the needs the bronze thrust washer as well as the shim cup to adjust any end float.


So as you have the ball type drive side bearing then there should be a shim cup with shims to adjust end float, there should be no bronze thrust washer on the timing side.


Suggest you try removing shims and see if that helps, also are you fitting the cam, breather and pinions at the same time? Could be the cam or something else binding.

Last edited by gunner; 03/17/21 10:42 am.

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Lots of good advice above. Lots of things to work through one by one to pin down the important variable.

Might be off target, but here have you installed alternator rotor or a spacer and torqued up the rotor nut to pull the crank all the way into the ball bearing? Adds to end float if that's the problem. You are probably onto this, but just in case.
also loosening bolts at top only , bottom only, front only or back only of cases might help you understand if there is a slight misalignment happening.

Ray


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So I unbolted the assembly and removed the shim cup as suggested, still locked tight. I then heated just the bush/case up with propane torch with everything bolted together and sweet baby jesus in his golden fleece nappies it spun. Seemed clear that it was the smallest bit that needed to come off. Took a 3 stone brake ctlinder hone, adjusted it so had minimal pressure. ran it in the bush for 10 seconds at very most, bolted everything back together and BAM it spins nice. Still a little resistance but very very little. Enough so I know it's not binding where it shouldn't and when it gets to temp it will still be in tolerance.
Thank you everyone for the suggestions!!
I'm still super curious where people get the info that there shouldn't be a shim cup or shims with the ball bearing when the factory parts book shows them in the assembly.. how did we learn that they arent supposed to be there? And why are suppliers selling those parts if they are leading to wrong engine assembly practices?
Anyways thanks again!!

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Shim and shim cups on ball bearing motor were likely an "as needed" part. So, it's shown in the parts book but 99 out of 100 motors may not have had them from the factory, hence the confusion.

With a roller bearing, you have a race fixed to the left-side case and a bearing fixed to the crank. Then, a thrust washer on the right side prevents the crank from slamming into the right-side case. Because the assembly is loose inside the cases you need to ensure that there isn't too much free play to cause undue wear on the thrust piece (or, god forbid, it spun out of its groove).

Ball bearings, meanwhile, are locked against the cases and the crank so the only use for the shims is to set running clearance on the right side. (no thrust washer used, but the original bush had a thicker lip than the later ones)

Lastly, when talking about "not binding when it gets to temp" keep in mind that all clearances are set at room temperature and take any expansion into consideration. You wouldn't want to run a motor that only spins when warmed up since too tight a clearance at room temperature will translate into too tight at running temp as well.

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Wasn't fitting the cam. Seems like it's good now. Thank you!

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Make sure you give the bush a good clean with hot soapy water as the brake hone will likely have left some abrasive deposits which could accelerate any wear on the parts.

The same principle applies after a rebore, using solvents doesn't remove abrasive deposits, it has to be hot soapy water.


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Originally Posted by Adam M.
By the way have the same problem with a bush being too tight in one place, so I assumed it's not in line with a ball bearing. Thought about scrubbing a tight spot CBS way but seriously afraid the clearance will be too big for a proper oil pressure. Took the block to the machinist again to install original type of a bush ( steel with bronze insert pegged together ). However until now it is not done yet. I was looking for possible tools to do a line boring and found a film about a Harley pinion cutter:
https://www.facebook.com/charley.dawidson.9/videos/1118128241966317
This tool is shown in 1.30 min and looks like could help with fine honing of the bush.

A piloted adjustable reamer.

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