[DeTomaso] Oil Smoke From Breathers

[wkooiman at earthlink.net]

Agreed, but "past the seals" includes the intake gasket.  You didn't exclude the intake gasket, but you didn't mention that it is an often overlooked source of "sucking oil".


-----Original Message-----
>From: JDeRyke at aol.com
>Sent: May 18, 2011 2:15 PM
>To: dfcex at pacbell.net
>Cc: detomaso at realbig.com
>Subject: Re: [DeTomaso] Oil Smoke From Breathers
>
>In a message dated 5/18/11 4:05:46 AM, dfcex at pacbell.net writes:
>
>> If I still have this issue, how does one test for valve guide or valve 
>> stem seals (with the engine together)?
>> 
>Dan, once in a while, someone will put a PCV valve in a rocker cover 
>upside-down (they fit either way), and high rpms will fill the cover with enough 
>oil to allow a mis-installed PCV to suck PINTS of oil into the intake by 
>vacuum and blow it out the tailpipe! The fix is to install the valve correctly.
>But smoke from a tailpipe usually means oil got into the combustion 
>chamber, and there are only two paths: past the rings, or past the seals, guides 
>and valves. Oil or heavy deposits of carbon on a sparkplug will confirm oil in 
>the combustion chamber. A leak-down test will confirm or eliminate the 
>rings as the leaky source, leaving only the guides. But there really is no 
>external test for bad seals. Someone's gotta go into the suspect set of valves, 
>pull the retainers & maybe the springs and examine the seals and guides. And 
>once you do that, its very little more trouble to replace them. I like 
>Perfect Circle all-teflon seals, but there are others. Sometimes, pulling the 
>intake and exhaust manifolds will allow examination of the ports behind the 
>valves; carbon build-up there almost always means leaking seals. With race 
>cars, ENGINES are regarded as consumable assemblies!
>As to what else may be causing it, worn guides are a fact of life for 
>performance engines but poor valvetrain geometery will make guides wear faster by 
>putting more side-thrust on valve stems. Very high rpms will also do it. 
>Then the worn guides take out their seals and you get smoke. Good luck- J 
>Deryke
>
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