Pvc???? Race vacuum pump?

Discussion in 'High Performance Modifications' started by docnascar, May 8, 2006.

  1. docnascar

    docnascar Veteran Member

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    PCV???? Race vacuum pump?

    At the car show Saturday night I saw this “race” engine BBC. The valve covers were completely sealed, no access caps for oil or pvc valve. However, going to the valve cover that would normally have a pvc valve on it was a hose, attached to a filter, attached to a pump. I asked the owner what that was for and he second it gives the engine more vacuum. He said the pump only takes about 1hp to run, but the benefits outweigh the lack of 1 hp.

    Two questions for a novice:
    What does a PVC valve do?
    What’s the benefit to his setup?
     
    Last edited: May 9, 2006
  2. Maliboost

    Maliboost Veteran Member Lifetime Gold Member

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    May 18, 2001
    sounds like a vacuum pump.

    did it look like this:
    [​IMG]

    or was it electric?

    either way, these folks http://www.gzmotorsports.com/vacuum-pumps.html make a bunch of them & they have a lot on thier site about them. Also www.moroso.com makes some of the best.

    To answer your question, a PVC valve vents off positive pressure, a vacuum pump creates a vacuum & keeps the crank case @ a vacuum. more HP is the bottom line. but.............. could cost street type relyability (less oil to the bottom of the pistons/pins).

    Bob
     
  3. docnascar

    docnascar Veteran Member

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    yeh, like that.

    How does it keep the same vacuum on the other side of the motor, if only one hose was going to one side, and not the other?
     
  4. onovakind67

    onovakind67 Veteran Member

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    The crankcase is open inside, so you only need to have one vacuum line to evacuate the whole thing.
     
  5. theflash

    theflash Veteran Member Lifetime Gold Member

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    I think you mean PCV, PVC goes to your kitchen sink ;)
     
  6. docnascar

    docnascar Veteran Member

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    Oops:p

    So the vacuum follows the oil channels throughout the motor?
     
  7. onovakind67

    onovakind67 Veteran Member

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    Crankcase vacuum affects everything inside the case. If you create a vacuum inside the case, you will suck air in through any outlet to the atmosphere. When I test my motors on the stand with a vacuum pump, I need to block off the oil ports and use a sealed distributor shaft to get a good reading of the sealing.

    The crankcase is open, there are oil return holes, holes above the cam, all kinds of holes between the two sides, so the vacuum inside the case is uniform.
     
  8. docnascar

    docnascar Veteran Member

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    Now I see. Thanks.

    So, what does the cute girl have to do with air pumps on a platter?:eek:


    [​IMG]
     
  9. Maliboost

    Maliboost Veteran Member Lifetime Gold Member

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    OK, I give waht? (& remember this is not the special projects section. LOL).

    Bob
     
  10. procharged 79

    procharged 79 Veteran Member

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    Apr 28, 2005
    central GA
    The whole concept for a vacuum pump is better ring seal, especially important when running the super thin low tension rings. Also good on boosted engines to help evac the crank case. I was told to run minimum vacuum when crusing around the street or they will starve the wrist pins of oil. Reher Morrison make a nice adjustable vacuum relief valve that bolts direct to the pump so you can adjust vacuum for street/strip, but it's a little pricey.

    Rob
     

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