Venting

Discussion in 'Fuel and Air Systems' started by BRog, May 13, 2018.

  1. BRog

    BRog Member

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    I have an original 1971 Dart slant 6 vehicle which I which I swapped out for a 340 motor. When I swapped the motor, I removed the black canister under the hood which was part of the vent system.

    So now I have a 1/4” vent line that runs from tank to engine compartment and I’m not sure what to do with it. Should this just be capped and venting will occur through cas cap?
     
  2. SGBARRACUDA

    SGBARRACUDA ROY FABO Gold Member

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    No I don't think you can do that as your cap isn't vented. Maybe use a vented cap or a fuel neck out of a 70?
     
  3. 67Dart273

    67Dart273 Well-Known Member

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    NO MOPAR CAPS were vented. (At least the cars we are talking about here)

    The ones from 70 (CA) and onwards were "pressure vacuum" in other words a relief valve

    Either leave the 1/4" tube "up high" for a vent, or re-create the 69/ earlier vent in the fill tube. From there, earlier, the caps were sealed

    Go to MyMopar, download a 69 or earlier manual and a manual for your car. The setup is detailed either in the fuel section or "emissions"
     
  4. brian6pac

    brian6pac Well-Known Member

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    Vent? I vent at the bar with a couple buddy's and a lot of beer!
     
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    • pishta

      pishta I know I'm right....

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      plumb it into the air cleaner, that sucks!
       
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      • Mr Gorsky

        Mr Gorsky I know words, I have the best words...

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        Run that vent line back into the fuel filter. Wix 33054.

        This is what I have on my Demon:

        fuelfilterwix33054.jpg
         
      • brian6pac

        brian6pac Well-Known Member

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        On the early cars they just vented to atmoshere. I would just run it up high so it wont leak fuel and vent it to atmoshere, or you could use it for a return line.
         
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        • diymirage

          diymirage HP@idle > hondaHP@redline FABO Gold Member

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          I would put the charcoal canister back in and plumb it in properly...or park outside
           
        • kiss

          kiss Well-Known Member

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          So first off, your vent line is 5/16", not 1/4". Mopar didn't switch to 1/4" vent line until 1972.
          Assuming you have a stock tank and fuel setup your best bet is to leave it vented to atmosphere. Put a small filter at the end to keep crap from getting into it. It's so far from the fuel tank that you won't have any insane vapor/gas smell issues. Don't worry about it.

          I wouldn't rig it to be a fuel return line unless you had a '72+ setup.
           
        • famous bob

          famous bob mopar misfit

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          I installed a new tank that had an extra vent line coming out the top , I ran it back and up in the trunk/ up high, w/ a couple of coils in it, and back down thru the trunk floor. Works fine , no fumes, no spillage on a roll over/ upside down. ' WHICH I HOPE NEVER HAPPENS !"