Rear main oil leak >

[Conaway2]

I just installed a professionally-rebuilt engine in my 31 Model A, and have a pretty bad oil leak in the rear. I can see the oil running down on either side of the inspection plate, and am pretty sure it’s not leaking from the cork seal at the rear of the oil pan.

I’ve been stewing over this for several days, and am really puzzled. Before I started the engine for the first time, I added about a half quart of oil to the valve chamber via the hole for the distributor shaft. 15 minutes later, there was a significant puddle of oil under the bell housing.

I have made sure that the oil return tube is not screwed in too far, and oil breather tube and cap are both clear. Now when I run the engine, only a few drops leak when the engine is running. After it’s been shut of for 20 or 30 minutes, a puddle of oil forms under the rear of the engine.

This has me stumped - somehow the oil in the rear of the valve chamber must be accumulating, rather than draining though the rear main cap oil tube or the external oil return line.

Any thoughts what may be causing this ? I’ll probably drop the pan this week and remove the rear main cap to inspect it.

Many thanks - Jim