I realize the PCV valve subject has been beaten to death and I did search. Here's my question: I have a nice old set of Cal Custom valve covers which have the large Offy breathers on them. I just finished putting my 327 together and am going to switch from the road draft tube to a PCV valve. Will having both breathers in the valve covers plus the one in the oil fill tube be too much ventilation for the PCV to work properly? If so I will mot likely make block offs for the valve cover breathers out of shim stock and keep the look. Thanks Posted from the TJJ App for iPhone & iPad
Well from my experience. I ran valve covers with no breathers on my 327 with the pcv in the road draft hole and the vent tube in front. It seemed to work fine but if i drove for periods at 80mph or just ran it to redline i would get oil out of the fill tube breather. which then sprayed onto the windshield. Once at the strip it blew the dam thing off so now its wired down. It could be that my motor is old and gets some blow by, maybe the zips with the higher fan. Since i dont get visable blowby at idle i decided to remove the pcv as the detergent oil should clean out the sludge and my intake runners will stay cleaner. I added the valve cover breathers and no more problem. Then for fun i decided to add a skirt to it like the 8ba fords used. I want it to pick up air there and go out the breathers when im driving. But i dont know if it does. No more oil on my windshield though so thats good.
I have dual large Moon breathers in my valve covers, plus a PCV valve and never have any oil out the breathers at any speed. If you do have an issue with the vent tube in front you could also plug it internally so it was not venting, but still there.
With too much inlet area, versus outlet, I suspect not. I would block of the extra breathers. For a PCV system to be effective, it has to have adequate flow and velocity. Without a size-metered inlet, you will have little or no draw-through. You are not exposing the crankase to vacuum, if the barn door is wide open. You will effectively have an open venting system, and the appearance of a PCV system. Posted using the Full Custom H.A.M.B. App!
When I was first putting my engine together I made the mistake of only installing a pcv line to one valve cover and no vent on the other. It would **** so hard air would whistle through the other seals on the engine. I installed a filtered breather on the opposite cover and that stopped. I still see a little residue on the pcv valve so it must still be ****ing up some of the g***es in the crankcase. Nic Posted using the Full Custom H.A.M.B. App!
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