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PCV Direction??

Discussion in 'Early CJ5 and CJ6 Tech' started by DanStew, Jul 17, 2005.

  1. Jul 17, 2005
    DanStew

    DanStew Preowned Merkin salesman Staff Member

    Lexington, South...
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    How does the PCV know what direction to go?? And what is the best direction or way for the system??

    I redid my PCV system today. I have the edelbrock intake with the PCV valve on the top back side of the intake. So that PCV is connected to a hose going to my rear carb inlet. Then i got rid of my grommet plug air filter on my valve cover. I installed a grommet with a 90 degree elbow and then attached a hose from that to a inlet on my air cleaner assembly. Now my PCV system is hooked up fine. I am just curious on how the system knows in which diection to flow. and would it be better to put the PCV valve in the valve cover, and put the 90 degree elbow in the intake. Or am i over annylizing this.
     
    DanStew, Jul 17, 2005
    #1
  2. Jul 17, 2005
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    The vacuum at the base of the carb will draw through the PCV valve, which has a restrictor orifice in it. This keeps the PCV system from looking like a huge vacuum leak. I don't think it matters which outlet on the engine the PCV is conected to, as long as it is there and there is a source of makeup air somewhere in the system. This is why the second hose is there.

    The one thing you definitely want to be sure of Dan is that there is a filter of some type on the intake side, so that you aren't drawing crud directly into the crankcase as the PCV sucks out the blowby through the other hose. In the air cleaner there is often a tiny filter element where the breather hose attaches just for this purpose.
     
    w3srl, Jul 17, 2005
    #2
  3. Jul 17, 2005
    DanStew

    DanStew Preowned Merkin salesman Staff Member

    Lexington, South...
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    Thanks Steve, that clears it up finally for me. Yes there is a filer for the fresh air, the outlet the aircleaner has si in the center of the air cleaner inside of the area where there is filtered air, so that is not a problem. I have to check on the PCV valve itself, i wonder if it is clogged,. I know my air filter was in hellacious shap,e so if the PCV is clogged, then i may have a reason why i have rough idle and hesitation

    Thanks!!!
     
    DanStew, Jul 17, 2005
    #3
  4. Jul 17, 2005
    Mark W.

    Mark W. Banned

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    Not sure as I can't really follow your explanation of what you hooked up but a basic PCV system should:

    Take air in thru one side of the engine (if a V8 or V6) or through something like the oil fill tube (like on a 134F) the air should then exit the engine on the other side normally one of the vavle covers this exit then goes to either the PCV port on the carb or to the intake manifold just below the carb. It is in this line the PCV valve it self should be located.


    I can help you out but I need to know what engine and manifold you are working with?
     
    Mark W., Jul 17, 2005
    #4
  5. Jul 17, 2005
    DanStew

    DanStew Preowned Merkin salesman Staff Member

    Lexington, South...
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    I am pretty much good to go. I was curious on how the PCV knows which direction to flow in regard to where the PCV valve is. I have a V6. I have the PCV valve in the rear of the intake manifold, with a hose connecting it to the rear of the carb. The fresh air side, it is coming from the aircleaner (filtered) to the valve cover with a hose.
     
    DanStew, Jul 17, 2005
    #5
  6. Jul 17, 2005
    Mark W.

    Mark W. Banned

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    Where exactly is this rear of the intake manifold port at?

    Is it somehow connected to the valve cover or the valley? Or is it in the intake plenum under the carb? This is the part that confuses me as I don't think I have ever seen a PCV that would connect the intake maniifold and the carb together the way you describe.

    I'm really quite curious if you have a setup unlike I have seen or if i'm just not understanding you correctly.

    Looking through Edelbrocks catalog I don't see any V6 manifold that would have a port that would connect to the crankcase.

    I have to be missing something here.
     
    Mark W., Jul 17, 2005
    #6
  7. Jul 17, 2005
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Sounds to me like you have a vacuum source at both ends of the PCV valve, that doesn't do anything. You need to hook one end to a valve cover like you mentioned, with the PCV valve direction towards the vacuum source.
     
    Glenn, Jul 17, 2005
    #7
  8. Jul 17, 2005
    DanStew

    DanStew Preowned Merkin salesman Staff Member

    Lexington, South...
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    The rear PCV valve is in the rear of the intake in the valley portion. So the vacuum is pulling air throguh the PCV valve, from in the valley. The fresh air is being pulled into the motor from the air cleaner assembly, into the valve cover.
     
    DanStew, Jul 17, 2005
    #8
  9. Jul 17, 2005
    181jeep

    181jeep Banned

    central valley, ca
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    Dan,

    I assume you are saying that your pvc is located in the floor of the manifold behind the carb and draws air at the rear of the valley.

    Ideally, a pvc sytem would have the pvc as far from the fresh air intake as possible. With your pvc intaking from the valley, ideally both valve covers would be fed fresh air. I like to see the pvc in one VC and fresh air in the other. The idea is to exchange all the crank case air with fresh air. I have seen the pvc and fresh air in the same valve cover which really does no good at all. Your setup is typical of jeep v6's that i've seen. Should work fine.

    JB
     
    181jeep, Jul 17, 2005
    #9
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