Crankcase Separator Clogged? (Oil-Out-The-Dipstick)

[baltimucho]

I'm chasing the ol' oil-out-the-dipstick fun. My compression is 90+psi cold, and I do not burn any oil... So I'm looking at the PCV system.


My cam cover has a working PCV valve connected to a small catch-can.


My PCV valve from the block seems to be working properly (blow-test), but the crankcase separator does not easily pass through air. When I blow through the hose, there is a lot of resistance and air is even pushed back. Is this normal, or is my block separator clogged?


I have 2 other blocks (one without an oil pan) and both block separators pass through air without any resistance, so I am curious if my separator is clogged or just reacting to the normal pressure inside the crankcase.

[MikeFleming]

The VC-mounted crankcase breather should pass air equivalent to a 3/8" tube - almost enough air to breathe through if you're not too exerted.

In any case that tube (and all associated connections) could easily be MUCH larger to vent crankcase pressure. 1/2"-3/4" should be sufficient.

[baltimucho]

I pulled the separator off the block, and blew through it without any resistance. So, the backpressure I was getting before was just the cranckcase pressure. I'll clean things up and put it all back together and hope for the best, but it looks like I'm going to have to start prepping one of my spare blocks for a rebuild.


Not that I'm totally unhappy about that.

[MikeFleming]

I pulled the separator off the block, and blew through it without any resistance. .

That whole path is closed (from the block vent to the intake) whenever the intake in under pressure when there is a functioning PCV valve in the path. You need to look at the other side vent - from the cam cover rear to the turbo inlet.

[baltimucho]

I'm going to look at everything as I put it all back together with a better understanding of how it works. My cam cover has a working PCV attached to a small catch can, but I will double-check all of that too.

[MikeFleming]

My cam cover has a working PCV attached to a small catch can, but I will double-check all of that too.

Should not be any valves, check-valves or flow restrictors in that line coming off the cam cover vent.

[baltimucho]

Ah... Good to know. I can fix that it. A P.O. put on a press-in, old-style PCV valve.

Even if I get the PCV worked out, given my compression test, I'm not sure I'll completely solve my problem.

I have 2 spare blocks, plus a ported head and an Engle TCS-111 cam. I think I'll finish the intake port job and build a new engine this winter.