So, my crank end float is .010, which is way too much. Can I install thrust bearings of .005 on one side and .003 on the other side to bring my end float to 002?  I've never had crank end float problems in the past and this is messing with my brain.

Thanks all

c

An S center main web & cap is 1/32" narrower in width than a non-S 1275 one. Why, only BMC knows...
If fitting a non-S 1275 crank into an S block, you will need to get +.030" thrust washer set. Surface grind the steel faces of the washers as required.

I have the opposite case- an EN40B S crank in an AA style block, I had to take ~.015" off standard washers to make them fit.

It sounds like you are dealing with say and Austin America crank in a S block. The thrust spacing on the two cranks are different. By the same token the two blocks are different. I have every thrust washer I have ever removed and I buy all O/S and under size thrust washer that come up. I select fit as close as possible then hand finish to size. Steve (CTR)

I just went through a similar issue recently with the S motor in my Traveller. Spridget thrust washers have a longer 'bevel' on the ends than Mini thrust washers. You can vaguely see the difference looking at the pictures in the parts section on this site. I figure (hope) they are interchangeable because I mixed-and-matched a Spridget pair and Mini pair to get the crank end float within spec. I have not tested the motor in anger yet ... only on idle for a few minutes.

Does anyone have a measurement in thickness of a 1098 vs a 1275 thrust washer set and is there any difference between inline 1275 and transverse 1275. Having some issues with an old 1275 non A+ crank in an S block.

Bruce