Best Rear Main Seal

[Terry Burtz, Calif]

The Lucky Star,

Thanks for asking for suggestions.

Any machine shop with a large enough metal lathe (something like 16x40) should be able to machine your crankshaft main journals to .015 inch oversize. Then have a crankshaft grinder grind to the specified dimension.

A crankshaft grinder could remove all of the material, but it may or may not be more expensive than taking it to 2 shops.

Regarding the connecting rod journals, your decision to leave them at Model B size is good for strength and fatigue life.

If your donor C crankshaft is not drilled from main to rod journal, you will have no problems when reducing the diameter of the main journals to Model A size. If your donor C crankshaft is drilled with a single hole from rod to main, the hole will break through at the main journal fillet when the main journal is turned down to Model A diameter. If your donor C crankshaft is drilled with multiple passages that are plugged at their ends, you may or may not have a break through problem.

Terry Burtz