[ponjohn]

Originally Posted by chiphead

The FM4040 (3" main) do have the reliefs in the thrust shoulders. They also have an oiling slot and not just a round hole to line up with the block oil passage.

Ditto to what Charlie66 says about checking each half of the thrust bearing. Sometimes the upper and lower halves of a thrust bearing are slightly different thicknesses at the thrust shoulders.

If you have .007" endplay with the upper insert only and .005" with the cap installed, there is a .002" misalignment somewhere. Usually requires feeler gauges between the thrust faces and the crank to find it. Then glass plate sand the thrust face of the tightest insert to get back to .007" with the cap installed. This prevents all the thrust load of the crank shoulder from being loaded on only the upper or lower half of the thrust bearing.

Interesting.