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Thread: PCV Breather ????

  1. #1
    Who runs them?
    I have one now but don't know if I should keep it or remove it. What does it do?

  2. #2
    In a boat that doesn't have an enclosed motor...ditch the hurts your A/F ratio.
    ohh hell...just ditch it all together for all boats, there worthless parts for performance.

  3. #3
    I do have an enclosed motor. If that makes a difference.

  4. #4
    Most marine engines don't use PCV's the fitting in the top of the manifold is usually open with no internals and just dump the vent to the side of the flame arrestor.

  5. #5
    pcv uses engine vacuum to draw fresh air through the engine. in the valve cover breather through the crankcase and drawn out through the pcv valve. Boats have little to no vacuum so they are useless, just have some kind of valve cover breather to let crankcase pressure out. I replaced my pcv valve with an open fitting and run it into the air cleaner just to get rid of the stinky blow-by.

  6. #6
    Chris J
    The PVC valve does have a few beneifits in a non race motor. By drawing in fresh air you signifcately reduce the "stinky blow by" which contaminates your oil. Also pulling a slight vacuum will eliminate oil leakage around the crank seals or other gasket that may be seapping. Plus if your carb orginaly was calibrated for a PVC valve it will proabably run rich without out.
    True if you run WFO it doen't do much for you, but if you do some cruising and idling there are a few benifits, not saying you need it just giving you a few reasons why it has one.
    Just curiuos, I haven't seen many Evac systems or a vacuum pumps on the hi pro motors. I would think if you are running dry, headers, turning off water at idle, or installed the tubes before the water dumps you would get the befinfits of a PVC plus make a few extra ponys.

  7. #7
    pcv is also supposed to help seal the piston rings, a friend is going to try a vacuum pump on his zz502 so we will see if it works, I didn't notice any vacuum pumps on the race boats at the worlds maybe it's not worth the expense. J.B. have you seen any race boats with 'em? P.S. new boat looks good, I saw some other pics of it that were interesting.

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