-=48Chief=-: Crank woes

I apologize in advance to the casual lurkers. This post will be pretty esoteric. I am trying to solve a couple of flywheel problems and want to share some pictures:

Problem 1: The crankpin does not pull through as much on the drive side as the pinion side, which appears to cause excessive side play at the rods when assembled with .067" thrust washers.

This picture below shows the pinion side of the crankpin, torqued. Crankpin end is about .033" below the nut face, not too bad:

This picture shows the problem end, the drive side crankpin end. Crankpin end is about .067" below the nut face, fully torqued. Note exposed threads on nut...

By reversing the pin, I concluded that the problem seems to be in the drive side flywheel, and not asymmetry in the crankpin itself. The taper (hole) in the drive side flywheel seems to be of too small diameter. This would also explain why the wheels seem too far apart, and very thick thrust washers would be required to get the proper .020" side play on the rods. Might also explain why I found that the last rebulder ground down the drive side case race on the inner surface with an angle grinder (to try to get proper crank end-play with a too-wide crank, I would guess).

Here is a photo of the outer surface of the drive-side wheel. Note the "Z-metal" mark and that there is no stamped timing mark.

Below is the outer surface of the pinion side wheel. This one has a problem too. When I insert and torque the new pinion shaft, and then mount it in the lathe to check that the wheel is true to the pin, I get about .015" wobble at the outer diameter.

Note the Z marking and the "84" casting tag. Note also that the balancing hole at the top of the picture is the only hole on this wheel, and the other crank has no balance holes drilled anywhere. The lack of drilled balance on one side makes me wonder if the wheeled are mismatched.