Leaking oil at rear main bearing

[Guest]

I have recently developed a rear main oil leak. My engine does not have a rear main seal. There are two small wood blocks that go into the cap and block to cover the join between them. There is a groove in the block and the rear main cap that appears to be a collector for oil that exits to the rear from the bearing. I presume there is a hole somewhere that allows this oil to run back into the crankcase.

My engine runs fine, as it has for 30 plus years since I overhauled it. Is it possible that this drain has somehow plugged after only 300,000 miles.

Any thoughts on how to fix this leak without pulling the whole engine????

Any and all help is appreciated.

[Rusty_OToole]

Could it be that crankcase pressure is forcing the oil out? How is your compression? Any blowby? Could be time for a ring and valve job.

[Guest]

Could be time for another overhaul. The compression has dropped from 95 when I overhauled the engine to 75-80 now. Also I know I have three cracked valve guides. Maybe I should just bite the bullet and fix it all. I was just hoping to get a few more miles out of it. Just the scots in me I guess.

[Guest rsd9699]

Wood and Indian - hmmmmm.

I guess you do not have a spare engine to examine? Or digital pictures from 30 years ago?

Maybe your wood does not work as well after 30 years.

Sorry - I could not resist......

But on the serious side - what kind of wood was used? Hickory or Oak or something special?

Ron

[rick60]

Excessive crankshaft end play can manifest itself as a rear main seal oil leak. Be sure to measure the end play before the engine is completely disassembled. Good luck!