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What to do with gas tank vent when all emissions components are deleted?

Discussion in 'Engine & Performance' started by AuroraGirl, Sep 16, 2019.

  1. AuroraGirl

    AuroraGirl Full Access Member

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    Truck Year:
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    I am replacing the gas tank on my 1980. The.. previous owner was my grandfather. There are three nipples coming off the gas tank sending unit thingy, and one of them I presume is a vent for the fuel vapor for the canister. That stuff is since been long gone on the truck. He had it plugged, but Im guessing some of my fuel issues was having a gas tank that couldn't vent... on top of the rust and bad gas gauge unit haha!

    What should I do to it?
     
  2. Frankenchevy

    Frankenchevy . Supporting Member

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  3. ali_c20

    ali_c20 Full Access Member

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    You could leave it plugged and buy a vented gas cap.
     
  4. Dan Miller

    Dan Miller K15SG

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    My tank has a ventcap like on an axle vent tube . It has only one vent line coming out of it tho, but it will vent. I will take a pic when I get home
     
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  5. AuroraGirl

    AuroraGirl Full Access Member

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    For the time being a drilled a tiny hole in the gas cap(just becsause I didnt have a vent on hand). where can I get a properly vented gas cap?
     
  6. Dan Miller

    Dan Miller K15SG

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    15689991049667623216400100364775.jpg
     
    Last edited: Sep 20, 2019
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  7. Edward Maxwell

    Edward Maxwell Junior Member

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    I bought check valve vents, built brackets and put them between the rear quarters and the inner bed side as high as I could. I had them just above the tanks on the frame when I deleted all my stuff and the first time I pumped cool gas out of the ground on a hot summer day my $4/gallon ethanol free expanded and ended up on the ground.

    The link above is the ones I used.
     
    Last edited: Sep 21, 2019
  8. Edward Maxwell

    Edward Maxwell Junior Member

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    Oh DO NOT ask butt pirate 4x what to do as those hillbillies will chastise you and tell you that you, expecting them to engineer your way out of this problem is pathetic.

    That was my experience, it sucked.
     
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  9. Frankenchevy

    Frankenchevy . Supporting Member

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    The only downside to a check valve is that it only operates in one direction. Theoretically, you’d want it to operate in both directions. To vent positive pressure accumulation and to draw air in to displace the fuel being drawn out. Probably not a huge deal in a lower fuel demand engine, though.
     
  10. Edward Maxwell

    Edward Maxwell Junior Member

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    Per Tanks inc website these valves are open to atmosphere to relieve pressure and vacuum avoiding performance issues and potential damage to the tank until you park your vehicle upside down at which time it checks and allows the driver time to depart the vehicle safely.
     
  11. Frankenchevy

    Frankenchevy . Supporting Member

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    Okay so you’re referring to a rollover vent like I linked to earlier on in the thread. That’s what I have.
     
  12. norman baker

    norman baker Member

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    i use mine as a return line from the carb low pressure , but replace the hose it is only rated for vapor, not liquid fuel.
     
  13. texasmike

    texasmike Full Access Member

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    When my truck is back on the road, I'm going to put my canister back on and reconnect the fuel tank vent line. Although a vented cap would probably be easier and just as good, like you, I don't know exactly what cap to buy that would fit and work properly.
     
  14. C10MixMaster

    C10MixMaster Full Access Member

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    I believe an 84 is a screw in gas cap, if so i dont think they sell a vented screw in cap. If it uses a cap with 2 ears on it you need one from a 73-74 that didn't have an evap system.
     
  15. Frankenchevy

    Frankenchevy . Supporting Member

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    drill a 1/16" hole in any gas cap and voila, vented cap.
     
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