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venting vs non-venting gas cap

Discussion in 'Flat Fender Tech' started by 47v6, Feb 22, 2015.

  1. Feb 26, 2015
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
    Joined:
    Sep 22, 2002
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    8,360
    The vent fitting is on the top of the filler neck (brass fitting) and returns to the front side of the filler well

    [​IMG]

    It runs up above the rear fender well, and loops back down

    [​IMG]

    This is what it looks like on the outside

    [​IMG]

    Not real pretty, but it works very well.
    I think I'll add a rollover valve as posted by auchuto.
     
  2. Feb 26, 2015
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

    USA
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    Hey, that looks great. I am going to get one of those rollover valves too. Thanks for the pics.
     
  3. Sep 7, 2018
    Grandpa Jeep

    Grandpa Jeep Member

    Peyton, CO
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    Oct 24, 2003
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  4. Sep 7, 2018
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Look for a locking cap as well - That is what I went to when I put EFI on the Blue '49. Seems to work well as the tank has a vent in it.
     
  5. Sep 7, 2018
    Grandpa Jeep

    Grandpa Jeep Member

    Peyton, CO
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    I'm not worried about locking, I just can't seem to get one that won't leak! Every vented one I have tried leaks through the vent when off camber or going around corners. I even tried plugging the vent with JB weld, which worked for a while but eventually fell out. Next I tried welding it, but took the temper out of the spring and it wouldn't fit tightly. This shouldn't be this hard!
     
  6. Sep 7, 2018
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    I've never seen an aftermarket cap that is listed for the Jeep application that is not vented. Maybe there's another application that crosses but is not listed.

    I used Liquid steel to plug the vent in 1973, but that may not work today. Look at McMaster-Carr or such for epoxy putty that is chemically resistant. You may have to buy $250 in putty to plug a single cap though.

    For the locking cap, I'd suggest taking it apart and putting continuous rubber sheet across the interior of the cap. I recall the vent goes through the lock cylinder, so you'll need a barrier to block the slosh and vapor. Again, McMaster-Carr sells sheets of chemically reisistant rubber that would work.
     
    Last edited: Sep 7, 2018
  7. Sep 7, 2018
    duffer

    duffer Rodent Power

    Bozeman, MT
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    [​IMG]:twist:
     
    Danefraz and sterlclan like this.
  8. Sep 7, 2018
    Greevesman

    Greevesman Member

    Napa, Ca
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    Oct 12, 2014
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    I got a vented one from Walcks and it does not leak off camber.
     
  9. Sep 7, 2018
    45es

    45es Active Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Naches, WA
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    Why not contact a company like Motorad which manufactures thermostats and gas caps. Explain your dilemma and ask for a suggestion. Might have a remedy.

    Contact MotoRad
     
  10. Sep 12, 2018
    Grandpa Jeep

    Grandpa Jeep Member

    Peyton, CO
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    I ordered this one which is non vented. It came with a paper gasket, but even after replacing it with a rubber gasket it still leaks. I wonder if htere is a better rubber gasket I could use.
     
  11. Sep 17, 2018
    Greevesman

    Greevesman Member

    Napa, Ca
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    Get one from Walcks.
    Or maybe the lip of you tank is bent?
     
  12. Sep 20, 2018
    Rondog

    Rondog just hangin' out

    Parker, CO
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    Aug 25, 2005
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    Part number MGC23
     
  13. Jan 12, 2019
    a3dhunter

    a3dhunter New Member

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    Jul 8, 2015
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    I measured the size and ordered a cap from tanksinc.com. Seems to work well as long as I don't overfill it.
     
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