PCV question.
Thread Starter
Safety Car
Joined: Jan 2000
Posts: 4,965
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From: Midlothian, VA
PCV question.
It's my understanding that the PCV system is designed to allow crankcase fumes to be sent into the intake manifold to be burned in the combustion chamber to lower harmful emissions. What fumes are produced in the crankcase that need burning? Thanks.
Melting Slicks
Joined: Aug 2000
Posts: 2,248
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From: Newland US
Re: PCV question. (C5Noir)
It's my understanding that the PCV system is designed to allow crankcase fumes to be sent into the intake manifold to be burned in the combustion chamber to lower harmful emissions. What fumes are produced in the crankcase that need burning? Thanks.
Mostly blowby from the combustion chamber. Also any oil fumes, which are dependent upon the volitility of the oil you use.
Years ago the gases/oil vapors were removed by a "draft tube" which depended on the air rushing past the open end of the tube and causing a pressure differential which caused the gases to be sucked from the crankcase. Those were the old days when each lane of the highway had an oil slick down the middle, where the evacuated oil/vapors were deposited. :(
Good luck.
Mark.
Le Mans Master
Joined: Oct 1999
Posts: 8,205
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From: Tucson AZ
Re: PCV question. (C5Noir)
There is always some combustion "blow-by" that gets past the rings, along with contaminants in the oil, like water, etc. You don't want them to re-condense and sludge up your clean Mobil 1 !! :yesnod:
Thread Starter
Safety Car
Joined: Jan 2000
Posts: 4,965
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From: Midlothian, VA
Re: PCV question. (MDT)
I guess I'm also wondering how pumping these fumes back into the combustion chamber lowers emissions, what harmful contaminants are we burning? Also, allowing these oil fumes to burn and especially in our case oil getting burned is lowering our octane and causing detonation. To me I would also think that the piston oil rings were the culprit of this massive oil blowby but I have also heard a tuner say it's the cylinder itself not being honed properly. This would make sense too because the oil rings couldn't seat properly and wouldn't have a near perfect seal thus allowing oil blowby. But with an improper honing wouldn't we be looking at more severe problems to our motors then oil blowby, like the rings expanding INTO the cylinder walls? Thanks guys, good topic here 
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[Modified by C5Noir, 1:45 PM 8/16/2001]
.[Modified by C5Noir, 1:45 PM 8/16/2001]
