I have read several posts on PCVs causing burning oil, especially with using valve covers lacking baffles. I was curious if anybody had some worse case examples of engines that consumed a large amount of oil due to using either an incorrect PCV or defective PCV ? Specifically in engines using baffles in the valve covers. Thanks.
How much oil can an incorrect or defective PCV really suck up (worse case) ?
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One quart within 60 miles, on a blown 383 stroker.
It had massive amounts of blue smoke out of the tail pipes when under boost, or when the engine was revved.
The 'short' valve covers were keeping the top of the baffles bathed in oil. A 'tall' set of valve covers, with baffles, cured it.
It had massive amounts of blue smoke out of the tail pipes when under boost, or when the engine was revved.
The 'short' valve covers were keeping the top of the baffles bathed in oil. A 'tall' set of valve covers, with baffles, cured it.
I used valve covers without baffles on a 350 and I had to add about a quart a week to make up for what went through the PCV. I tried those cheap baffled grommets and they didn't do squat. Then I bought and installed these: http://www.summitracing.com/parts/MOR-68790/ They are inexpensive and worked great. The engine didn't use any oil after that.
Thanks for the info.
Actually running some aluminum valve covers that appear to be slightly taller than stock with baffles cut out from a pair of stock SBC valve covers and custom mounted. I dropped my car off at the engine builder for some diagnosis and he supposedly says the PCV is not closing at all and is a continuous vaccum sucking oil mist into the carb and is the probable cause of this excessive oil consumption on this recent rebuild. I am extremely hesitant to fully believe this. I went down this path before the rebuild and found out it was working fine. I am averaging 1 qt 100 miles or so.
Actually running some aluminum valve covers that appear to be slightly taller than stock with baffles cut out from a pair of stock SBC valve covers and custom mounted. I dropped my car off at the engine builder for some diagnosis and he supposedly says the PCV is not closing at all and is a continuous vaccum sucking oil mist into the carb and is the probable cause of this excessive oil consumption on this recent rebuild. I am extremely hesitant to fully believe this. I went down this path before the rebuild and found out it was working fine. I am averaging 1 qt 100 miles or so.
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How much oil can an incorrect or defective PCV really
yea ,i like you ,have been there , but mine was ring broke .
no baffle or even a long oil fill with the valve in it stopped it , it used same as yours is .
take valve out the hole and the oil fill cap , lay a piece of card board over and hold off to one side ,see if it flaps enough to raise off cover on oil fill hole . broke ring or bad out of round cylinders .
yea ,i like you ,have been there , but mine was ring broke .
no baffle or even a long oil fill with the valve in it stopped it , it used same as yours is .
take valve out the hole and the oil fill cap , lay a piece of card board over and hold off to one side ,see if it flaps enough to raise off cover on oil fill hole . broke ring or bad out of round cylinders .
Thanks for the post...I totally agree. However the car is with the builder and apparently he has his own way of troubleshooting. I have tried this previously (before build) and it was defineately not sucking oil. That's what really makes me suspect it may not be the issue at hand even though I would be happy it would be such and "easy" fix.barnym17 said:
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The PCV valve flows air all the time, at low vacuum levels it opens completely...at high vacuum levels it closes and restricts flow such as at idle speed.
Its primary function is to prevent crankcase explosions and will close completely, it acts as a one way valve in this circumstance.
http://www.filtercouncil.org/techdata/tsbs/94-2R1.pdf
Since they cost $2 this should have been your first part replaced when you had oil consumption problems, you haven't replace it yet?
Its primary function is to prevent crankcase explosions and will close completely, it acts as a one way valve in this circumstance.
http://www.filtercouncil.org/techdata/tsbs/94-2R1.pdf
Since they cost $2 this should have been your first part replaced when you had oil consumption problems, you haven't replace it yet?
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