Pcv negative pressure?

Rjhoward32006 · Aug 2, 2016

Well thats what i'm trying to fix before now it has had positive crankcase pressures. Enough to blow oil out the breathers on the valve cover when i tried that.
Compression and leakdown tests are within spec. Thats why i am now going to the negative pressure set-up to see if it helps. I just think the way i have it now might be a little too much negative pressure but from what i have researched it can have up to about 20in hg vaccum. I bought a gauge so i will test tonight or in the am and see what it is.

Rjhoward32006 · Aug 3, 2016

So i tested a couple of different size ports on the intake to rout this negative pressure and i now have it at 7in hg vaccum at idle which falls quickly under acceleration. Hopefully this will do the trick. I guess i will update in a couple rides to post if it has helped at all. Atleast the motor won't hydrolock anymore

altfuel1991 · Aug 6, 2016

I had an experience several years ago on a small block where there was an internal leak from the intake causing it to pull vacuum on the crankcase. It actually vaporized and sucked the oil out of the engine and burned it. It did not burn it fast enough to see any blue smoke but it sucked out 4 quarts in less than 3000 miles. Found a hole in the underside of one intake runner.

Rjhoward32006 · Sep 19, 2016

Well after searching amd searching and trying more things than i can count i finally found the oil leak!!!!
It only leakes under load with oil pressure from about 50-70 psi, a crack in the timing cover. And one the psi spikes its like a stream of oil, and then the cooling fan catches it and covers everything....