1982 PCV Sucking Oil
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Joined: Apr 2018
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From: Northern Kentucky
1982 PCV Sucking Oil
Just completed top engine mods...mild cam, 180 heads and renegade intake. She’s running good, however at WOT the PCV is sucking oil. I’m using the short valve covers with baffles but they are not the stock ones that I previously had on. Before this mod I did not have this issue. Any Ideas on what is causing it?
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
No, not entirely, but the PCV valve as you may know has a little spring in it to resist high engine vacuum during idle, deceleration, and cruising. The spring is there to prevent too much oil vapor from being sucked up into the intake and burned. If the spring fails in any way, the engine will suck up too much oil and oil vapor. If the PCV is also clogged, there is no place for the pressure inside the crankcase to go. This usually leads to the blowing out of seals, dipsticks etc... I would replace the PCV first with the correct PCV and try again. Is this a new motor by chance? If not, how many miles are on this motor?
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Joined: Apr 2018
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From: Northern Kentucky
Not a new engine, but I just did a mild cam, heads and renegade manifold install. 60k on the motor. Like I said, it was not doing this at all before I did the cam swap., however these are not the stock valve covers. I’ll try a new PVC valve first.
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
I would give it a try and see what happens. If it still does it, you may have to go back to the stock covers. My 383 is using stock covers for an 82 with a rather huge cam with no issues like that. I do have the stock PCV in it right now, but I do have a custom one to put back into it as well that actaully idles better with the other one which is a M/E Wagner PCV. Read about it here... http://mewagner.com/?p=1130
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
Zero vacuum at WOT.
You say you just installed a new intake? Did you seal the intake gaskets at the bottom too? Oil mist can be withdrawn from the lifter valley right into the intake port.
You say you just installed a new intake? Did you seal the intake gaskets at the bottom too? Oil mist can be withdrawn from the lifter valley right into the intake port.
Race Director
Joined: Jul 2015
Posts: 13,082
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From: SW Florida.
high rpm pcv is not sucking oil. you put a top end on tired rings and i betcha you started driving harder. you now have more blowby than you had. the rings are blowing that oil past the pcv. or else it was already like this and OEM valve covers baffled the blowby better. try the old valve cover if it fits over new valvetrain. or research puke can.
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
All good reply's and I was going to give a very similar response on my first reply, but thought I would go easy and not have the OP go *****-nilly all over the place swapping things and chasing his tail and getting nowhere like a lot of posts do for a lot of people which stops just short of..."have you changed your four-way flashing fluid yet?". If the OP would post a pic of the covers he is now using, that may be helpful, but I would be leaning more to the engine issue (mechanical) causing the issue as was touched on, but does not mean that that is defiantly the issue. Once you track down the root cause look into the PCV I posted. For a modded motor, it does work great and it is tuneable. The post that your PCV doesn't suck oil at WOT is correct since there "shouldn't" be any vacuum, but the vacuum comes from the "decel" part of the equation and the sucking then starts which is where the oil may be coming from, maybe not. Either way, I hope you can track down the issue and be happy and enjoy your 82. 
Team Owner
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From: Crossville TN
I don't know exactly what heads you have installed. I will just caution that in some head swaps, the oil return holes need to be modified to guarantee a good drain-back flow. Otherwise, the valve covers fill with oil and you get the situation you now have. Just something to check out....
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...