air flow direction for 308 cut-off valve | FerrariChat

air flow direction for 308 cut-off valve

Discussion in 'Technical Q&A' started by Doc, Jan 17, 2004.

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  1. Doc

    Doc Formula Junior

    Sep 13, 2001
    Latham, New York
    Full Name:
    Bill Van Dyne
    I have the cut off valve ( that little round vacuum valve in the air injection system located above the gearcase housing ) off of the car and noticed an arrow on the bottom of it . Not paying attn when I took it off, which way should this be installed? I assume the arrow should point to the drivers side of the car, indicating air flow from the air cleaner box. Is this correct?

  2. wolftalk

    wolftalk Formula Junior

    Jan 27, 2004
    san franciso area
    Full Name:
    doc didn't get an answer on this, and now I'm curious :)

    on the 328, the valve is bedded down in some hoses, so you can't see the sides. However, you can feel the arrow/triangle on the side of the valve housing (below the white cap) pretty easily.

    so, is the arrow pointing to the drivers side (the arrow would be on the firewall side of the valve), or the passenger side?

    The valve seems to allow a little airflow when closed in the direction of the arrow. If the arrow is pointing to the drivers side, then the exhaust check
    valves are always flapping a little. I haven't tried turning the valve around to see what happens.
  3. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    Arrow points towards driver's side. Flow goes through filter--> lower airbox--> hose to valve-->dome valve--> T-fitting--> splits to R/L air injection valves/manifolds. Mine sealed tightly when not vacuum-activated open.

    On a related matter, check the "T"-fitting to rust holes & the check valves can rust over time. I think they have an "anti-backfire" configuration to prevent anything in exhaust from getting back and melting dome-shaped valve. If you need pictorial I have one on replacing check valves (GM parts) also.

    :) Carl
    [email protected]

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