motocooney

iTrader: (6)

So Mellon Tuning is saying that you need to plug the breather from VC to intake and Evoryder is saying let it vent???

Which is correct?

I also had pressure escape from my oil cap and a good amount of pressure venting from the breather on the drivers side. I also attached a hose to direct the hiss coming from the valve cover/intake line.

I'm performing the test with the tester connected directly to the turbo inlet. MBC/compressor line plugged. PVC/valve cover still attached. Valve cover/intake line venting

Is this correct?

I am able to get 23psi ( I run 23psi) but it's leaking from the oil cap and slowly bleeds off...

Also, will running big cams affect the ability to hold pressure?

motocooney

iTrader: (6)

Bump for an answer. I've read just about every thread on this and no definitive answer. Should the valve cover breather line be vented or capped off?

drb

iTrader: (39)

Let the valve cover vent. To minimize the amount of air that escapes from the valve cover area:

1. Do the boost test with the engine at normal operating temperature, as this helps minimize the blow-by at the piston rings.

2. Make sure your PVC valve is working and therefore not letting pressure from your intake manifold to enter the valve cover area.

3. Get the engine close to TDC by slowly rotating the crankshaft pulley clockwise until leakage from the valve cover area is minimized.

Big, aggressive cams can increase the valve overlap and therefore they will increase the amount of leakage that you see at the valve cover area.

Dan (drb)

motocooney

iTrader: (6)

Sweet thanks man....I'm picking up a new pcv tomorrow. I know the engine is good...compression is right on. Just kinda freaked me out that the oil cap was leaking so much pressure. I think all thefactors....big cams, cold engine, not necessarily at TDC, pcv.... added up to pressure in the VC. I don't think the oil cap is meant to see any real pressure...I have a nice HKS cap and everything seems good with that

ethan169

iTrader: (3)

Sorry for not seeing your posts earlier man. I totally forgot about this thread. I leave the breather hose unplugged now and it always leaks air. For what its worth i never take the time to find TDC and see if it stops. I doubt it will stop it completely and if it doesn't then whats the point. I do have high lift and duration cams GSC S2's (274 with 11.1 and 11.2mm if i remember correctly) Im fairly certain these aren't helping my issue at all. I replaced my PCV valve with a brand new OEM one and even put a almost new IX turbo on my car and had the same issues. So I have came to the conclusion that this is normal.

I do seem to be burning a little bit of oil ever since i installed the cams though. I have still yet to decided weather that is form my valve seals leaking or just from excessive blow by as i do have small traces of oil in my charge piping (no catch can). Compression test returned good results and far within spec. 80k stock bottom end.


Good luck with everything

Ethan

mdsevo06

iTrader: (41)

With an OEM PCV, I noticed I didn't need to do this, it acked like a check valve. But when I replaced it with a NAPA PCV, it would allow air back in to the valve cover. I boost leak test at 20psi.

turboGarrett

iTrader: (7)

I recently replaced my pcv valve with one from napa and noticed the same thing during my boost leak test. I assume the pcv valve should not let any positive pressure from the intake manifold to the valve cover?

barneyb

Before you install it, put the valve to you mouth and blow through it. The valve should only allow air through one way. If NAPA is selling a PCV valve that doesn't work this way it is the wrong valve. Take it back.

sna08

iTrader: (3)

Pcv(positive crankcase ventilation) is meant to allow air in the valve cover to recirculate back to the intake... And not the other way around. So I would double check the napa pcv

sna08

iTrader: (3)

Wow I didn't even realized I brought this back from the dead but good read anyways