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RE: Valve Cover Venting

To: "'Andrew B. Lundgren'" <>
Subject: RE: Valve Cover Venting
From: Ruggiero Larry Lt Col AFRC/XPXS <Larry.Ruggiero@AFRC.AF.MIL>
Date: Fri, 15 Nov 2002 08:51:13 -0500
Hey Andrew...

I'm not sure if putting a modern PCV valve into the valve cover tube would
solve your specific problem. I've thought of inserting a "modern" PCV valve
into the system, but only from the tappet cover vent tube. You didn't
mention how your tappet covers are set up (breather on the front, rear, or
perhaps not at all) but I see a potential problem in that the oil that does
escape through the valve cover vent tube won't backflow into it because it's
got a very small orifice hole. The valve cover tubes are set up that way
because they're air inlets, not the venting outlets, and excessive inlet air
is not desireable. If you optimize the tappet cover breathing portion of the
venting loop, then theoretically all should be well. If your engine is worn
enough to be producing excessive blow-by, then the misting will only get
worse otherwise. Putting a "modern" PCV valve into the rubber hose between
the valve cover tube and your carb tube  might contribute to more oil
pooling in the hose, since it can't readily backflow into the valve cover.

Warner Robins, GA

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