new model A owner, modification questions

[darrylkmc]

bdave_mcc,

I would pull the engine, remove the crankshaft and examine all of the bearings.

If your problem is isolated to only the rear main cap, there are people on this forum who have had success with having just the rear main poured and line-bored. I have no personal experience with this procedure.

A rear main crack at the babbitt like yours shows has likely separated from the cap itself. This will cause oil to flow under the babbitt and and out the rear, bypassing the slinger and/or seal.

Darryl in Fairbanks