My engine started using oil all of a sudden. It's a G.M.P.P. 350HO with pocket ported heads , Comp. Cams 268xe cam & ZZ4 intake.
-started using 1 quart every 350 miles
-comp. test 170 psi all cylinders
-no leak down test performed
-mechanic replaced valve seals
-I replaced intake gaskets
-pcv filter & air cleaner housing clean and dry
-still using oil
-unchanged G-tech times
-heavy oil film on intake plenum floors & intake ports on heads
-removed heads, all cylinders fouled from oil
-no obvious cylinder scoring yet
-cross hatch still visible on cylinder walls
-motor has approx. 20,000 miles
-not sure what to look for, any thoughts?
-sorry for the long post and thanks in advance.

 

i'd look at the intake gaskets and for warpage or anything that would prevent a good seal

 

What are you using for a PCV system?

 

The PCV system is the factory setup. The air cleaner is a dual snorkel from an 84 Camaro.

 

ZZ4 intake on a 350HO??!?!???

don't know about that one.

 

I bought this engine in 1997. Up until and including 1998 the 350HO had heads #12356026 and was rated at 300 h.p. In 1999 GM added the Vortec heads and bumped output to 330 h.p. The short block and cam are the same in both engines. The original style heads allows the use of the ZZ4 intake. I get this information from the GM Performance parts Catalogs which I have sitting in front of me as I type.

 

You didn't by any chance change the valve covers at about the same time as this started, did you?

 

I'm still using the original valve covers. The only thing out of the ordinary was washing and re-oiling the K&N.

 

The heavy oil film in the plenum is almost screaming "blowby", or possibly an inoperative PCV. That's why I was curious about your valve and system.