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PCV valve question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Predator, Sep 26, 2001.

  1. Predator

    Predator 1/2 ton status

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    Is it okay to run a PCV valve on each valve cover and "T" them into the carb port?

    My K5 Buildup: <a target="_blank" href=http://www.geocities.com/xci10u2/K5.html>http://www.geocities.com/xci10u2/K5.html</a>
     
  2. Pugsley

    Pugsley 1/2 ton status

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    You can do it, but it's really not necessary - one PCV valve, and one breather is a much better setup, providing for better vapor removal - the dual PCV's would cancel each other out to a degree.

    Special thanks to those lost from IAFF Locals 94 and 854 - You shall never be forgotten
    <a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
     
  3. RedDwarf

    RedDwarf 1/2 ton status

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    Yeah, you can do it.

    Not sure what you mean by "cancel eachother out" Pugs.
    You've got high pressure on the valve side of the PCV's and low pressure on the carb side.

    Poundin' the ol "pavment"!
     
  4. Pugsley

    Pugsley 1/2 ton status

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    It's kind of hard to explain, but the two PCV's will actually cause the vapors to stay low in the crankcase - there needs to be a source of fresh air coming in to actually push the vapors to the source of vacuum.

    Special thanks to those lost from IAFF Locals 94 and 854 - You shall never be forgotten
    <a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Only two openings in the motor (breather and PCV) if you have both openings "sucking" how does the system work? If you can't draw air in through one port, its going to have to get in the crankcase from somewhere, be it through seals, rings, etc...

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
    No anti-theft measures on your truck? No pity when its stolen
     
  6. RedDwarf

    RedDwarf 1/2 ton status

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    It doesn't "suck", positive crankcase pressure pushes open the valve.

    Where does the fresh air come from on the stock setup(no breather)?

    Poundin' the ol "pavment"!
     
  7. Pugsley

    Pugsley 1/2 ton status

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    The OEM setup gets fresh air from around the air cleaner - the breather is in the air cleaner housing, connected to the passenger side valve cover.

    Special thanks to those lost from IAFF Locals 94 and 854 - You shall never be forgotten
    <a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
     
  8. RedDwarf

    RedDwarf 1/2 ton status

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    Oh yeah, I forgot about that aluminum deal that comes out.

    Poundin' the ol "pavment"!
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    You are of course, right.

    Manifold vacuum keeps the valve "closed" and as engine vacuum decreases, the valve is allowed to "open".

    Fresh air, at least on my '80 somethings case, comes from a fitting on the air cleaner.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
    No anti-theft measures on your truck? No pity when its stolen
     

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