No announcement yet.

PCV (Again) read the guide, searched EVERYWHERE!


PCV (Again) read the guide, searched EVERYWHERE!

  • Filter
  • Time
  • Show
Clear All
new posts

    PCV (Again) read the guide, searched EVERYWHERE!

    Ive searched, read, read the turbo guide, read the BIG thread on Honda-Tech about it.... And like everyone else, STILL confused!

    I have ONE simple question. Is the point of having vacuum at the "breather box" to SUCK (vacuum) the gases out?

    In the honda-tech thread, the guy did all the tests on a NA car which doesnt apply to the FI guys. If more gases are being created and need to excape faster, then why not just let the gases exscape into the atmosphere? (unless vacuum gets the gas's out faster)

    The main reason I ask all this is because I have a RevHard manifold for one. For two I dont have a pcv spot for this "check valve" so it sounds like its not a big deal. The turbo guide shows xenocron idea of doing a setup but I dont see the point in it. (again unless SUCKING the air out of the crank case is the point of a PCV system)

    HaberDasher- What do you mean closed circuit (your setup) vs xenocron open circuit.

    Im just making this harder then what it really should be?

    BTW: There are two hoses that are in the "breather tank" on the back of the block. One is the line that goes to the PCV "check valve" and the other looks like it goes to.....? I cant tell from my own picture and my motor/car is at the parents. it looks like maybe the head or even the TOP of the block, my guess is the head since air is coming into the head from the valve cover and thats how it leaves due to the vacuum?

    Im just going to shut up and get owned very quickly hopefully by xenocron or haberdasher or one of you PCV gurus!

    As of right now it appears that you just cant LEAVE the "breather box" open. Im thinking xenocron has the right idea, but I dont uderstand haberdashers idea in the first place.

    ::sighs:: help :'(

    Air flows into the top of the head at the breather under low load, no boost conditions and out the crank case ventilation port on the back of the block through the PCV and into the Intake manifold. This is good as it crank case pressure is bad.

    First reason its bad, it pushes up against the pistons as they are making power and trying to come down. If you are sucking, this helps the pistons come down and frees up power.

    If there is an abundance of crank case pressure...oil can get past the rings and into the combustion chamber...obviously bad. This also shortens the life of the rings I believe.

    So yes...the point is to relieve as much pressure as possible. You could just leave everything open, but that isnt friendly to the environment. Plus, if you can configure vacuum under all operating cirumstances from the crank case vent, you get more power and longer engine life.


      So the ideal point of a PCV system is to get the gases out faster. The only reason they are being PUSHED out is because of the pistons coming back down which is putting pressure on the rings, correct? The object is to suck the pressure out and let fresh air in through the valve cover?

      What is Haberdasher talking about a open/closed circuit setup?


        Open = gases to environment

        Closed = gases get recycled and usually end up in the combustion chamber and then through the exhaust

        Optimal setup:

        Filtered air entering the valve cover breather.
        Vacuum pump sucking air from the crank case to exhaust (post cat) or to air. Or through a good filtering system and back into the intake.