Reply to "Rear Main Seal Leak"

quote:

Originally posted by Tom Todak:
I recently built a 381 cubic inch cleveland, Forged crankshaft (probe),the rear main seal leaks afrer 3000 rpm,drip drip approx.every 20 seconds.under 3000 rpm no leak,, I have tried 2 neoprene and 2 rope seals (1 new old stock asbestos)still a leak. the crank measures correct and true with a dial indicator.no cracks or porousity can be found in the block or cap. I'm tired of ( and my engine dyno guy is i'm sure and are mystified as to the cause, at this point we are concidering machining anouther block ! Also I am running a stock oil pump and the leak happens with or without the valve cover breathers installed,, Anyone have any ideas?

You have tried running the Engine "Without the Valvecover Breathers in Place"? I hope that you DID NOT plug the V. Covers All together, if so, in a few seconds of running; you would have blown out the crank seals. But I would expect this to cause more than just a drip every 20 seconds or so. You must have Breathers OR keep the Positive Crankcase Ventilation in place. If you have removed the PCV Valve and hose, replacing it may 'help' your leak problem; because of the Vacuum it creates in(where else)The Crankcase. Also check to make sure that it IS Engine oil leaking and Not gear oil/lube leaking out of the Transaxles' FRONT seal. Last I fully agree with GP, the rear seal pin or lack of RTV in the open hole, once the pin is removed; is suspect.