bad pcv valve caused my blow by?

[Kibby]

I posted awhile ago I thought I had blow by from the rings being bad. But I took it out and drove it. Got into it and had no issues whatsoever. Not popped dipstick no power loss. A friend suggested I replace/check the pcv valve.

 

[IncorpoRatedX]

I had an old PCV valve that would get stuck when it was cold out. At idle the car would smoke, once I got into throttle there was no smoke at all, once it warmed up the car wouldnt smoke at idle. I changed the PCV valve and checked compression, PCV should make a rattle sound when you shake it, this one didnt make any sounds.

 

[prove_it]

And only use OEM! Aftermarket valves fail fast and hard.

 

[belize1334]

A bad PCV valve will allow positive manifold pressure to cause positive crank case pressure, which in turn can pop dipsticks, etc. It doesn't "cause blowby", which is necessarily exhaust escaping past the rings - but it can cause the same symptoms.

 

[Kibby]

Well that was really all it did was pop the dipstick. It doesnt have much power being stock minus the 2g kaf 16g and broken downpipe which does a 12-20psi spike in the upper rpms.I ran a compression test got 135 150 150 135 I think thats what it was. I know I should run a leakdown to which would confirm if I have blowby. Jus been so busy lately with my s10 blowing the rear brake line the both front springs snapping on my crx. Gettin there. Pending weather ill che k the pcv valve tomorrow.

 

[mrt0mjones]

Did you attempt to do a wet compression test? (oil in the cylinder) to attempt to see a change in the result?

 

[Kibby]

No and im not going to. Results can vary with that depending on where the oil goes/coats. Im gonna run a leakdown test

 

[Kibby]

This pcv valve is beyond done. Blows air in both sides with barely any restriction. Sooo ill order a new one and go from there. Thanks for the help guys.

 

[belize1334]

Fyi, 130-150-150-130 is low enough on 1 and 4 to get some blowby regardless of the condition of the PCV. Put a spring on the dipstick (small hose clamp, spring, hanger) just in case. You don't want to be sputtering oil on your exhaust manifold. That's how fires happen.

 

[donkeylips]

I'm surprised nobody has mentioned putting a plastic check valve in line with the PCV valve to make sure you only have flow going the proper direction.

 

[Kibby]

Quoting belize1334:
Fyi, 130-150-150-130 is low enough on 1 and 4 to get some blowby regardless of the condition of the PCV. Put a spring on the dipstick (small hose clamp, spring, hangupper) just in case. You don't want to be sputtering oil on your exhaust manifold. That's how fires happen.



Since ive got the money to get another engine/rebuild. I drove it like I stole it. 11-20psi spikes and full throttle pulls. No dipstick pop, no funny business with the car. im really suprised a pcv valve could cause blow symtoms as far as the dipstick and such.

So next Wednesday pending weather im going to the track and see what she runs. Im hoping for low 14's or to touch a 13.

 

[coyotes]

is that your compression? I don't remember my exact numbers but one of my cylinders is like 15-20psi lower than the rest. I am running on wastegate pressure though so less boost than from the factory. My dip stick pops up sometimes but only a centimeter or so and doesn't spew oil. I don't know the condition of the PCV valve, it's likely original.

 

[Kibby]

Im running on wg pressure. But due to my flex pipe leaking it spikes up to about 20psi. Runs 11 til like 5k then rises with the rpms. I need larger injectors. Dsmlink says 88% this is on 550's which I thought would have gone a bit further. Im justgonna get 1000's or bigger then install the fmic and situate a downpipe and custom catback. Ive got a hks hipower catback off my 1g so ill see if I can mod it to work. And yes those are my compression numbers

 

[coyotes]

Good to know. I was thinking about raising the boost a little bit eventually but I am ok with my power levels right now (I have turboback and FMIC). I have a second engine being built so I'm not too worried about blowing this one up. I would rather not, though.