Why do you need an oil catch can?

[Eric870]

This is a newbee question, What do you need a oil catch can for? I asking because I have a 1990 and every time I step on the gas I get a puff of Blue smoke and I was wondering if a oil catch can will help.

Thanks
Eric

[LGAFF]

West Coast Answer: Greener Planet

Real Answer: Stops oil (Vapor)from being sucked into the plenum through the PCV system. Sucking oil into the engine is not good for performance, your 90 has smoke because there are no valve seals on the exhaust valves....changed in 91.

[jonszr1]

plus oil makes for tons of detenation . causing the knock sensor to pull timing to stop it..when you pull your plenum just lookinside the manifold .its scary how much oil is in it.

[Aurora40]

If you ever pull your plenum off, you'll see why. A few tablespoons of oil will probably pour out of it. Enough that it doesn't seem good.

If you get a puff of smoke when you get on it, perhaps you aren't getting on it often enough?

[Ccmano]

Other than the valve stems and the PCV system, oil is also pulled into the intake from the oil vents that go from the heads to the injector housings. When the head to injector housing bolts get loose (they all do) and the gasket gets old and dried up, oil gets sucked in straight across the gasket. I was shocked when I pulled my injector housings to see all the oil. Ever since I put in new gaskets and retorqued the bolts the oil smoke has largely disappeared. I do however still plan to put in a catch can.

H

[XfireZ51]

=Jeff= and I were discussing this just the other day. He bought a catch can and I held off in doing so. I pulled my
plenum last night just because I had nothing else to do and decided I'm getting a catch can. I don't recall ever seeing that much oil in my Xfire manifold like I see now. Were the LT-1s and L98s like this?

[bobbyhi]

If this is the "thing" to do I would suggest that someone list the materials needed to and how to install. I know that there are threads out there that do expain but they are scattered about. Just one thread with everything needed including where to hook everthing up

[USAFPILOT]

I agree...I get a puff when I start it...i never noticed it but my brother saw it the other day. Maybe it is one of these problems...but a very minor one indeed.