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A65 crankshaft end float #489866
05/12/13 8:33 am
05/12/13 8:33 am
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sussex
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jamie weeks Offline OP
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I am re building an A65,when checking the crank end float without any shims or the shim cup, it is 6 thou ,so I have fitted a 3 thou shim to make the tolerance 3 thou.But this is without the shim cup and from the calculation of subtracting the number on the crank from the number on the cases it should need 17thou approx.I have obviously fitted the thrust washer etc and checked with a dial gauge,it turns nicely.Is this commom ?
thanks jamie

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Re: A65 crankshaft end float [Re: jamie weeks] #489882
05/12/13 10:34 am
05/12/13 10:34 am
Joined: Sep 2004
Posts: 796
Farnham, Surrey, UK
gunner Online content
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AFAK as long as you have the correct end float with everything fitted together you should be ok.

I believe the way to check end float is to put a dial gauge on one end of the crank, zero it and then lever the crank sideways. If everything is correct the dial gauge deflection will be 3 thou which shows the correct number of shims have been fitted in the cup.

Although you can calculate the theoretical number of shims needed based on the previous endfloat & cup thickness, its the final fully assembled reading which counts.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 crankshaft end float [Re: jamie weeks] #489912
05/12/13 3:27 pm
05/12/13 3:27 pm
Joined: Aug 2001
Posts: 4,308
Santa Barbara, California
KC in S.B. Offline

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I had an experience lately where even though I thought I had everything together right, and it's not my 1st motor rebuild, I somehow had the thrust washer not seated in it's proper spot. If it is rotated, as when you lift the crank and turn it while fitting, the washer can stick to the crank and fall back in the wrong spot. The result is it is sitting High, and takes up too much space. If not too late, and you are really concerned, it might be worth checking that. Mine was SO obvious, that I had to take it apart, and found the problem.


Down to 1 BSA, 2 Triumphs, 1 '56 Chevy
Oops,.. add 1 Sporty
Re: A65 crankshaft end float [Re: jamie weeks] #489967
05/12/13 11:49 pm
05/12/13 11:49 pm
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Missouri
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BSA Nut Offline
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I agree with Gunner...total dry assembly of the lower end is the best way to check for correct end play. Math is good in some instances, but proof is in the pudding, as they say. Dry fit the crank in the two halves, bolt them up,set a dail up on a tang from the case. Measure,adjust, and finally assemble.

Is one thou to three thou what they recommend on these? I dont have a manual in front of me at the moment.

wink

Re: A65 crankshaft end float [Re: BSA Nut] #489973
05/13/13 12:21 am
05/13/13 12:21 am
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Gnashville
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Originally Posted By: BSA Nut

Is one thou to three thou what they recommend on these? I dont have a manual in front of me at the moment.

wink

0.0015" to 0.003"


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
Re: A65 crankshaft end float [Re: DavidP] #489976
05/13/13 12:26 am
05/13/13 12:26 am
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Missouri
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Thanks David...knew that was close.

Re: A65 crankshaft end float [Re: jamie weeks] #489997
05/13/13 1:51 am
05/13/13 1:51 am
Joined: Aug 2001
Posts: 4,465
Owego, NY, USA
Mark Z Offline
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I agree with KC that something is amiss. The shim cup is about .018" thick, there should be at least that much clearance.

"...total dry assembly of the lower end is the best way to check for correct end play."

To elaborate on this:
Assuming this is a drive-side roller bearing crank ('66 or later, you didn't specify the year), you should have the crank sprocket and alternator rotor mounted, and the rotor nut torqued down when checking the end play, in order to squeeze the shim(s) firmly against the bearing inner race.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: A65 crankshaft end float [Re: jamie weeks] #490079
05/13/13 7:14 pm
05/13/13 7:14 pm
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Auckland NZ
Ignoramus Offline
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other things I would be looking for on disassembly (and yes you do have to start again) as Mark and KC said ....if the motor was designed with a shim cup thickness and you are hitting spec without it something is wrong.

the things to look out for ;
Inner bearing race is hard up against the web, and not sitting on a kind of wear mark "lip" where either a race previously spun or a shim cup skidded or what ever

that if you haven't checked the outer race (assuming post 66 crank here) is firmly bottomed out in the case you could loose .016 there easy

third a good alternative to fitting everything up on the crank (alternator ect) is use a piece of pipe and a washer to load the bearing inner race

let us know what you find

Last edited by Ignoramus; 05/13/13 7:16 pm.

"There's the way it ought to be and there's the way it is" (Sgt Barnes)
Re: A65 crankshaft end float [Re: jamie weeks] #490271
05/15/13 2:32 am
05/15/13 2:32 am
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Cape Carteret, NC
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Mr Mike Offline
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You may well have a crank that was not part of the original case assembly. I could never get those numbers to work for setting endplay. When measuring with a dial indicator make sure you tighten the rotor nut so the whole assembly is sandwiched up tight against the crank cheek.

Mr Mike

Re: A65 crankshaft end float [Re: jamie weeks] #490287
05/15/13 7:06 am
05/15/13 7:06 am
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Gnashville
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Just wondering, how does one properly tighten the rotor nut without assembling the whole primary drive?


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
Re: A65 crankshaft end float [Re: jamie weeks] #490329
05/15/13 2:41 pm
05/15/13 2:41 pm
Joined: Aug 2001
Posts: 4,308
Santa Barbara, California
KC in S.B. Offline

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Just find a clean piece of wood, and stop the crank from rotating. As use certainly still have the cylinder off. Find something to use as a spacer on the crank, to replace those parts. That way you do not need to keep installing the gear and rotor each time you tighten the nut. I have a cut off piece of pipe........ works fine.


Down to 1 BSA, 2 Triumphs, 1 '56 Chevy
Oops,.. add 1 Sporty
Re: A65 crankshaft end float [Re: jamie weeks] #490330
05/15/13 2:50 pm
05/15/13 2:50 pm
Joined: Jan 2012
Posts: 109
sussex
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jamie weeks Offline OP
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I have found the answer,the roller bearing outer was not fully 'home' in its rebate, have now pressed it fully home with a press,and have shimmed the crank with the shim carrier fitted to an end float of 2 thou,many thanks for all your help.I just felt it was not right and that proved to be the case. regards jamie

Re: A65 crankshaft end float [Re: jamie weeks] #490419
05/16/13 4:26 am
05/16/13 4:26 am
Joined: Aug 2001
Posts: 4,308
Santa Barbara, California
KC in S.B. Offline

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Glad you found it, and have that off your mind !! Your intuition was telling you right!


Down to 1 BSA, 2 Triumphs, 1 '56 Chevy
Oops,.. add 1 Sporty
Re: A65 crankshaft end float [Re: jamie weeks] #491181
05/22/13 10:14 am
05/22/13 10:14 am
Joined: May 2013
Posts: 283
Missouri
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When doing this, I was amazed by the amount of endplay prior to tightening the rotor nut. I guess this elaborates on BSA's issue of the bronze bushing not controling the side movement of the crank, which explains the centering effect of having bearings on each end.Improperly fitted, and the crank would drift in and out, with nothing to positively position the shaft.

Re: A65 crankshaft end float [Re: BSA Nut] #491516
05/24/13 1:09 am
05/24/13 1:09 am
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Posts: 3,884
Cape Carteret, NC
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Mr Mike Offline
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BSA nut,
While many plain bearing engines have a floating crank, it would have been nice to have a ball and roller on the primary side to fix the crank to the left side. They did in on b50's, a roller bearing motor, and early A65's had only a ball bearing on the primary side.

Mr Mike

Re: A65 crankshaft end float [Re: jamie weeks] #491549
05/24/13 8:23 am
05/24/13 8:23 am
Joined: May 2013
Posts: 4,843
Rotherham - S. Yorkshire
Allan Gill Offline

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I had a little look at that idea Mr Mike, I wondered if it would be possible to fit a ball race directly next to the roller. This though would be trying to find a roller that is as thick as the spacer, removing the oil seal and modifying the crank case, it could work but it would be a lot of hassle.

Im getting my engineer to make me a version of the outrigger plate that Mark Parker uses. I have supplied him with a bearing, which needs a sleeve between that and the crank. The sleeve is for 2 reasons

1) to get a bearing of decent OD but slim (about 7mm) the ID is larger also.

2) with the belt drive kit I will be using, the whole setup comes very close to the case, and securing the outrigger properly to the crank, the end of the crank needs to be lengthened.


beerchug
Re: A65 crankshaft end float [Re: jamie weeks] #491687
05/25/13 2:15 pm
05/25/13 2:15 pm
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Cape Carteret, NC
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Mr Mike Offline
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You can fit a ball bearing in place of the roller. I did it on my Lightning. Works great. The still make those inch series ball bearings. Then you can throw the thrust washer in the bin. You give up some radial load capacity but for normal street use the ball is adequate and you don't have to fuss with shimming for endplay.

Mr Mike


Last edited by Mr Mike; 05/25/13 2:16 pm.
Re: A65 crankshaft end float [Re: jamie weeks] #491753
05/26/13 2:14 am
05/26/13 2:14 am
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Posts: 4,465
Owego, NY, USA
Mark Z Offline
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"...and you don't have to fuss with shimming for endplay."

Really, Mike? I thought I had read that shimming is still required, although you don't have to torque down the rotor nut to measure.

This is important to me right now because I'm in the process of rebuilding a '65 lower end, and staying with the ball bearing setup.

One thing I've been wondering through all this, how is the crank located with respect to the cylinder bores, by the drive side or by the timing side of the crankcase? I've noticed that my '65 crankshaft is shorter than my '66, from web to web outer, and the counterweights are thinner. Now either the ball bearing inner race stands prouder in the case than the roller, or the thrust surface of the timing side of the case is built up to make up for the shorter crank and the lack of a thrust washer.

I know, I'm raising two or three different questions at the same time. I guess the bottom line is, if the reference point for locating the crank is the timing side, then it would seem that shimming is necessary.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: A65 crankshaft end float [Re: Mark Z] #491793
05/26/13 12:26 pm
05/26/13 12:26 pm
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Stone Creek OH USA
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Rich B Offline

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Mark

The ball bearing motors used a lot of different pieces. The housing for the timing side main bearing has a thicker shoulder, the crank is different (as you note), and of course the bearing.

You check "end play" with crank unloaded (no spacer, sprocket, or rotor). Same spec as the roller bearing motors. All you are checking is the running clearance between the shoulder on the TS main bearing and crank. Once you have your .0015" - .003" clearance, you are good to go.

When you assemble the primary, when the rotor nut is tightened, you have running clearance....I still call it "end play" even if it does bother/confuse some. The crank is locked to the ball bearing and has correct clearance on the TS. Seems to work fine.


Life is too short to drink cheap, bad beer.
Re: A65 crankshaft end float [Re: Rich B] #491848
05/27/13 12:28 am
05/27/13 12:28 am
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Cape Carteret, NC
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Mr Mike Offline
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Mark,
I do not understand Rich’s explanation. We have been around on this before and we’ll have to agree to disagree. Here is my explanation of converting a roller bearing motor back to a ball bearing. First I agree there are differences in the thickness of the flanges of the bush and possibly the crank width, however, the ball bearing and a roller bearing have identical dimensions. The ball once assembled locks the crank to the primary side. The only movement of the crank laterally is the minute running clearances of the balls in the race. This movement is imperceptible…maybe .0002” I insert the same cup and shims that was used on my roller bearing so that the I centralise the rod journals under the bores. This is not of great concern because there is plenty of side to side clearances of the rods on the journals and between the piston and the small end. Now as I bolt the cases together I have to be sure that when I tighten the cases there is some clearance between the flange of the bush and the right side crank cheek. But since I have removed the thrust washer altogether (.065” thick), there is plenty of clearance so you won’t put the crank in a bind as you torque up the case bolts and studs. There is no need for a thrust washer whatsoever…It’ll only rattle around. With a roller motor that clearance has to be .0015-.003” because the crank is NOT fixed on the primary side. It shucks back and forth limited on the timing side by the thrust washer and on the primary side by the lip on the roller bearing. There is no such movement with a ball bearing.

I do not know how else to explain it.

Mr Mike

Re: A65 crankshaft end float [Re: jamie weeks] #491866
05/27/13 4:29 am
05/27/13 4:29 am
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Owego, NY, USA
Mark Z Offline
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I've read both of your explanations (twice), and I'm not so sure there's any real disagreement.

Nowhere does Rich say that the crank floats.

You both say that the crank has to be shimmed "so that the rod journals are centered under the bores" (in so many words), and that's what I really wanted to know.

It sounds like you may be saying, Mike, that if the clearance turned out to be something more than .003, that would be ok (i.e., because the crank does not float). But since in my case, the end play has to be measured and the crank shimmed, we may as well shoot for the .0015-.003 spec.

But I understand now your PREVIOUS quote, "you don't have to fuss with shimming for endplay." The key words here are "for endplay". I first misinterpreted that statement as "you don't have to shim the crank".

Ok thanks both of you, I think I'm back on track.

Last edited by Mark Z; 05/27/13 4:31 am.

Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: A65 crankshaft end float [Re: Mr Mike] #491912
05/27/13 5:07 pm
05/27/13 5:07 pm
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Originally Posted By: Mr Mike
But since I have removed the thrust washer altogether (.065” thick), there is plenty of clearance so you won’t put the crank in a bind as you torque up the case bolts and studs. There is no need for a thrust washer whatsoever…It’ll only rattle around. With a roller motor that clearance has to be .0015-.003” because the crank is NOT fixed on the primary side. It shucks back and forth limited on the timing side by the thrust washer and on the primary side by the lip on the roller bearing. There is no such movement with a ball bearing.


What holds the drive-side ball bearing in place when the engine is hot?It's only an interference fit in the crankcase when the engine is cold.
Heat the crankcase to 100 C.,and see how tighty (or loosely) that bearing is held in position.

Re: A65 crankshaft end float [Re: Pete R - R.I.P.] #491922
05/27/13 7:52 pm
05/27/13 7:52 pm
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Have you guys considered that if you remove the thrust washer (which I think is nominally 1/16th ) you will create a much larger "cavity" between the crank web and the bush end on the ts.

I cant see any way that wouldn't loose you a bit of oil pressure ....or oil flow to the big ends to be more precise

might be a bit theoretical but I will skip that mod


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
Re: A65 crankshaft end float [Re: Mr Mike] #491963
05/28/13 12:16 am
05/28/13 12:16 am
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Stone Creek OH USA
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Mike

Mark is NOT converting a motor. He is rebuilding a 1965 motor that had no thrust washer, was designed to run a ball bearing, and has a lot of different pieces than you are familiar with your one motor you rebuilt and converted.

The details of your conversion are useful for someone rebuilding a 1966 or later motor. But, none of that information is useful on a 1962 - 1965 motor, which is a different animal. If anything, the info adds confusion.

Rather than keep saying you don't understand what I am saying and we have to disagree, look at a 62 - 65 motor for once. Then maybe you will understand the differences. And understand the differences in set of the bottom end.


Life is too short to drink cheap, bad beer.
Re: A65 crankshaft end float [Re: jamie weeks] #491978
05/28/13 1:02 am
05/28/13 1:02 am
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Cape Carteret, NC
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Mr Mike Offline
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Rich,
You are right ...I am only speaking only of a conversion of a roller motor to a ball. If I was putting an earlier ball motor back together I would want to make sure that there was clearance so as not to preload the bearing when tightning the case which would result in almost immediate failure. So putting in some shim to centralise the journals under their bores is important but don't put in so much that it binds the crank. In a coversion from roller to ball there is plenty of clearance with the thrust washer removed. If I left the thrust washer in I would have to make sure that there was a clearance.

Pete, as the motor heats up it heats up fairly slowly and somewhat uniformly so as not to lose the interference fit. Additionally the coefficient of friction of aluminum is about twice that of steel so it likely gets a little tighter. I do not know why BSA did not put in a retainter plate like on a B50. They must have thought it was unnecessary.

Iggy, It is unlikley that removal of the thrust washer will have any appreciable effect on oil pressure. It is not pressed in there...just captured there.

Mr Mike

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