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  #1 (permalink)  
Old 04-24-2022, 07:13 PM
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Cobra Make, Engine: BDR build #983, FRM 392
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Default Eliminate the PCV valve

Can I eliminate the PCV valve on my SB Ford Racing Motor (351W stroked to 392) and replace with a valve cover breather? I already have a breather on the other valve cover. Just wondering if the PCV is necessary or if I can replace with another breather.
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  #2 (permalink)  
Old 04-24-2022, 07:50 PM
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Quote:
Originally Posted by SBSerpent View Post
Can I eliminate the PCV valve on my SB Ford Racing Motor (351W stroked to 392) and replace with a valve cover breather? I already have a breather on the other valve cover. Just wondering if the PCV is necessary or if I can replace with another breather.
That was my configuration. I had a Roush 427IR with the 8-stack. Your only consideration would be if you have emissions testing/inspection that may require it. But if you already have it why get rid of it? The breather will get some (although not much) oil in it.
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Old 04-24-2022, 09:34 PM
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Quote:
Originally Posted by twobjshelbys View Post
That was my configuration. I had a Roush 427IR with the 8-stack. Your only consideration would be if you have emissions testing/inspection that may require it. But if you already have it why get rid of it? The breather will get some (although not much) oil in it.
"But if you already have it why get rid of it?" Purely for aesthetics. I am not required to have the PCV for state emissions and I find that a breather on the valve cover looks better than the PCV.
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Old 04-25-2022, 04:24 AM
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The Cobra replica I used to own was set up specifically for track use. It had openings in each valve cover plumbed to a vented catch can. Given the relatively low miles driven and the frequency at which I changed the oil, it worked. The only drawback was that I had to disconnect on of the hoses to add oil to the engine.

The two reasons most often cited for a PCV system are keeping your engine oil cleaner by actively removing bypass gases, and protecting the environment by drawing those bypass gases back through the intake to be burned. As my latest car was built as a cruiser rather than a track car, I wanted a PCV system that would not detract too much from the illusion of a 1963 engine in my Cheetah. I modified a pair of real finned aluminum valve covers so one connects to the intake with a PCV valve and the other has a filtered breather large enough to use as an oil fill.



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Old 04-25-2022, 07:20 AM
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As many have stated in various threads regarding a PCV, it serves a purpose on
street driven cars continually removing crankcase contaminants and mitigating
crankcase pressure. A double breather setup relieves crankcase pressure but
does not provide any other benefit. Racers don't care about eliminating crankcase
contaminants as most perform an engine teardown annually so the double breather
methods is both simple and convenient.

I use a ME Wagner PCV which can be tuned to the engine size and HP. The line is
then routed to an air/oil separator before heading back into the carb for
elimination via combustion. The air/oil separator (catch can) sends only purified
air into the carb to avoid mixing oil mist with gasoline (source of fouled plugs).

The ADD W1 air/oil separator also has a convenient dipstick to check waste oil level
in the can. The bottom threads off for disposal or you can plumb a drain hose/valve
in the bottom.

ME Wagner PCV
Dual Flow Adjustable PCV Valve – M/E Wagner Performance Products

ADD W1 Baffled Catch Can
https://www.addw1.com/collections/oi...-configuration

The above combo has worked well for me even at 500+ cu. in. and 650HP.

Last edited by Unique427; 04-25-2022 at 07:30 AM..
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Old 04-25-2022, 12:45 PM
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Removing the PCV can cause oil consumption and leaks due to the crankcase pressure. We actually run vacuum pumps in our race engines to create a negative crankcase pressure which helps the rings seat and reduces oil leaks. Although in stock type configuration its lower but it still functions this way when plumed correctly. Even though it's considered an emissions control device they've been on engines before there was any emissions regulations for these reasons.
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