Valve Stem Oil Seals

[cleszkie]

My 72 K5 (350/350) puts out a small plume of blue/white smoke (oil) every time I start it up after its been sitting. After the initial cloud, the thing runs without any noticeable smoke. The plugs all look good (no oil deposits or ash), so I'm hoping the oil is not blowing past the rings (good compression on all cylinders). My gut feeling is that oil is leaking down my valve stems into the combustion chamber. I bough a set of valve stem oil seals (small black rubber o-rings that go in the valve stem groove right below the valve lock), and have installed them in one head, but the smoke is still there (I run dual exhaust with no crossover). I do not see how these would seal any oil out of the combustion chamber judging by their location on the valve stem. My question is this: Do I need to replace the valve guides to keep oil out of the combustion chamber? Are there any other seals that I do not know about in the valve train that I can replace? Any help would be much appreciated!

 

[chevyracing]

Go to NAPA and get some umbrella valve seals. That should do it. Sounds like your guides may have too much tolerance as well, but the umbrella valve seals are the thing to do for now. They are relatively inexpensive.

John

 

[cleszkie]

John,

I noticed that when I replaced the O-ring valve stem seals on the Blazer that there where some umbrella seals on the intake valves only. I did not replace these. Sounds like I should consider going back in there and replacing these as well. Is it normal to combine the O-ring seal with an umbrella seal, and why don't any parts stores list these umbrella seals (I've seen them in Comp Cams catalogue). Do the exhaust valves run too hot to use umbrella seals as well?

Thanks.

 

[chevyracing]

I run them on all 16 valves with o trouble what-so-ever. I think they are about 2 bucks each at NAPA and the usually have about a ga-zillion of them in stock. Be careful of the ones you get because the heads need to be machined (usually) for the ones that have the metal bands around them.

It is normal for some kits to come with oring seal and umbrella seals (8 of each) I replace the eight o-rings for the umbrella seals and use the o-rings for my shifter peg on my Harley.

John