Oil Consumption Mystery
I have about 3,000 miles on a 347 I assembled last summer and for some reason the rings havenít seated. Iím getting 145 to 155 psi compression on all cylinders (10.3:1 compression ratio) and about 20% leak down. The engine runs great and has good power, but the big issue is that it is burning a quart of oil every 500 miles or so and I canít figure out where it is going. The following is a list of things Iíve observed.
There is no blue smoke coming out of the exhaust under any driving condition.
The tailpipes are not oily and the spark plugs are light tan with no indication of oil.
There is no oil leaking from the engine, the engine bay and underside of the car are very clean and there are no oil spots on the garage floor.
There is no indication of oil in the coolant.
The oil got dark very quickly, which I assume is due to the blow-by.
When I built the motor, all of the top compression rings were gapped between 0.017-0.018, and the lower compression rings were gapped between 0.020 and 0.022.
Iím running Valvoline 20w-50 oil.
When the electric fan cycles off I can see smoke coming out of the valve cover breather. When the fan is on the smoke isnít obvious.
The PCV system is working fine.
There is a baffle plate in the valve cover where the PCV valve fits in.
Since Iíve been running the motor, Iíve burned about 5 quarts of oil. If all of this were coming out of the breather Iíd expect to see a lot of oil film in the engine bay. There is some, but not much.
Any ideas on where the oil is going? At this point, Iím figuring it is going out the breather, but Iím not sure. I plan on rebuilding the engine soon to deal with the blow-by, but I want to make sure I also fix the oil consumption problem at the same time.
Thanks for any suggestions.