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Vapor system delete?

Discussion in '308/328' started by Doug, Sep 8, 2009.

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  1. Doug

    Doug Formula 3

    Nov 13, 2003
    1,473
    Louisville KY
    Full Name:
    Doug
    #1 Doug, Sep 8, 2009
    I have a '77 and it has no air pump or smog equip. When I purchased it, the 3 outlets on the carbs had cut hoses that were plugged. Is it better to plug all 3 independently or should I plumb each to the vapor canister. It appears that there is an open outlet coming off the bottom of the canister.
     
  2. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,150
    way north california
    Full Name:
    chris morse
    #2 chrismorse, Sep 8, 2009
    Hi Doug,

    It is very tempting to simply rip off and "save for future owners" all of that hastily thought out trash that was appended to our beloved cars - in the name of clean air.

    You need to follow the system to make sure you do not delete the tank venting system, or you will be climbing a hill one day to find out that the car is running out of gas, because the fuel pump cannot pull fuel from a totally closed container, it needs to allow some air in to replace the used fuel. Conversely, you need to allow the pressure build up in the tank someplace to go. As air and fuel expand from ambient, (or engine) heat, they create pressure that needs to bled off. I haven't done this yet, but if you have all of the old parts, you should be able to build a system that can vent pressure without leaking gas and a system that allows filtered air in to replace used gas. My simple start on the system, (after removing everything) is to install a oneway valve with a filter to admit air. I am working on a way to vent pressure without leaking gas if i flip over. While we are at, it would be nice to allow the engine to consume, (burn) the vapors rather than leaking them to the atmosphere.

    still working on it,
    chris - a builder behind the redwood curtain :)
     
  3. Doug

    Doug Formula 3

    Nov 13, 2003
    1,473
    Louisville KY
    Full Name:
    Doug
    #3 Doug, Sep 8, 2009
    I was referring more to the diagram in post #6 in this thread http://ferrarichat.com/forum/showthread.php?t=193587
    The 3 outlets coming off the carbs were cut hoses with plugs. Can they remain plugged or is it better to run them all together back to the charcoal canister? All the other fuel related lines are intact, just no smog pump anymore. Do they need to be on a closed circuit, or can they be open?
     
  4. hanknum

    hanknum Formula 3

    Nov 1, 2003
    2,050
    Santa Barbara
    Full Name:
    Henry
    #4 hanknum, Sep 9, 2009
    Doug,

    I posted a similar question in the other thread...
     
  5. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,367
    NY
    #5 Steve King, Sep 9, 2009
    Leave them plugged. The fuel tank in the earlier cars are vented through the filler cap. If you still have the carbon canister with the hoses attached to the fuel tank just leave it. If you want to remove it you need to cap off these 3 hose fittings in the top of the passenger side fuel tank. Follow the schematic and you will see there is a vacuum valve that opens to suck fumes back into the carbs . This should not be open during normal driving.
     
  6. Mike Florio

    Mike Florio Formula Junior

    Jun 19, 2003
    599
    NW Rural Nevada
    Full Name:
    Mike Florio
    #6 Mike Florio, Sep 9, 2009
    I have a '75 GT4 and have been a bit alarmed with the smell of gas in the engine compartment. No leaks, but I suspected the charcoal canister. So I rebuilt it replacing the charcoal with stuff I bought from an aquarium supply. I posted a thread on the rebuild and some folks made fun of me. I don't care, there are no more gas vapors under my engine cover.

    If everything works correctly the vapor recovery system does what it is supposed to do - keep the tanks from drawing a vacuum without venting gasses to the atmosphere. There are three ports on the vapor canister - one, on the bottom, goes to the three way valve and then to the tanks. The other (larger one) on the bottom, is open to atmosphere; and the third, on the top, goes to the forward bank intake manifolds. To avoid any possibility of sucking charcoal into the intake I had installed a small transparent fuel filter in this line. After rebuilding the canister I can see that this is overkill unless something catastrophic happens to the canister.
     

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