ZR-1 Net Registry Forums - View Single Post - Plenum Pull Advice, Starter Rebuild, MAP Sensor Info

A26B · 03-06-2013

The oil you are seeing is normal, comes to the plenum via the PCV system when crankcase pressure is at its greatest.... WOT/high rpm. The LT5 unique PCV system with it's dual PCV valves was the result of crankcase pressure experience during development. After playing hard and being shut down for awhile, oil in the plenum will sometimes cause a puff of smoke on startup, due entirely to oil draining down the plenum runners.

I've never installed an oil catch can, but do think it is a good idea. Keeping oil out of the intake is always a good idea.

I wouldn't be concerned about the oily residue. It's only a problem if it collects in the hose and interferes with the vacuum sensing.

03-06-2013	#35
A26B Join Date: Dec 2003 Location: Arcadia, OK Posts: 3,404	Re: Plenum pull advice The oil you are seeing is normal, comes to the plenum via the PCV system when crankcase pressure is at its greatest.... WOT/high rpm. The LT5 unique PCV system with it's dual PCV valves was the result of crankcase pressure experience during development. After playing hard and being shut down for awhile, oil in the plenum will sometimes cause a puff of smoke on startup, due entirely to oil draining down the plenum runners. I've never installed an oil catch can, but do think it is a good idea. Keeping oil out of the intake is always a good idea. I wouldn't be concerned about the oily residue. It's only a problem if it collects in the hose and interferes with the vacuum sensing. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.