Originally Posted by 71fj40guy
Currently I'm running a spectre pcv valve on one valve cover and a breather on the other. Would it be bad to run 2 breathers instead, would it effect engine longevity?
currently the motor is a stock 290hp gm performance crate motor. It's installed in a daily driven 1971 Toyota FJ40 Land Cruiser.
Pulling oil over the PCV would indicate that either (or both) the PCV is missmatched to the engine, the PCV has failed, there is insufficient or missing oil seperation media before the PCV, the compression rings are damaged, not seated (broken in), end gap too wide, or worn out (any of these results in excessive blow by), the engine is operated at elevated RPMs and high loads (this resuts in high amounts of blow by and lots of internally flying oil which has gotta come out somewhere).
Certainly a compression and a leak down test are in order up front as if the problem is in ring sealing for what ever reason, nothing else will solve the problem so there's little sense in spending a chunk of money on band-aids only to find it's still bleeding to death.
The PCV is intended to remove blow-by products from a normally healthy engine so first this means there's not a lot of blow by to begin with. Secondly blow by consists of compression and combustion gases that get past the rings, for the most part this is a combustable mixture that is rather corrosive when it mixes and circulates with the lube oil so burning it adds a lot of years to the engine's life. The presence of lube oil passing the breathers tells you that either the filter/seperation media is missing or failed in a normally healthy engine or that the engine is not healthy having a serious problem that is producing so much blow by that the seperation media is overwhelmed.