fuel tank venting clarification

Discussion in 'Troubleshooting & Diagnosis' started by biggrass, Jun 1, 2017.

  1. biggrass

    biggrass Veteran Member

    342
    0
    Aug 30, 2006
    GURNEE, IL
    Hello everyone I have a 72 which has had all the eec equipment removed. The fuel tank vent tubes are all capped, and has a non vented gas cap. Just want to make sure 72 did not come with a vented gas cap. I do get a large swoosh noise when the cap is removed. To alleviate this can I run some sort of vent from the drivers side tube? Does it have to be as high as the filler neck tube? Also any recommendations on a new non eec tank?
     
  2. flybye70ss

    flybye70ss Veteran Member

    883
    2
    Dec 6, 2002
    Allen, TX
    If it is all sealed up, couldnt you just use a vented cap? The tank needs to breathe.
     
  3. Zspoiler

    Zspoiler Veteran Member

    2,211
    116
    May 6, 2012
    Federal Way, Washington
    The tank needs to breathe .Other wise you can have problems with vapor lock .And the car won`t run. Different years went about it in different ways according to emissions laws.I would check out the Nasty Z-28 April 18 article "lots of pressure of the gas cap."in the club archives. On my 1979 Z-28 RS Camaro even though I don`t have to run through emissions anymore .I still run my stock gas tank emissions set up. Because its doesn`t add to performance to be without.And the car gets a little better gas mileage because the gas vapor goes to "carb".Instead of the air.
     
  4. Chevrolaine

    Chevrolaine Veteran Member Gold Member

    I believe if all the tubes are capped it can't vent. What flybye said - it needs to breathe.
    Originally, no it didn't have a vented cap as it vented through those various tubes.

    Sharp car btw!
     
  5. giggity

    giggity Veteran Member

    674
    12
    Mar 18, 2013
    Pearland, texas
    just buy a vented cap, you dont need all that crap. The reason they went to non-vented caps was because of the emissions nazis in the early 70s...my 1970 came with vented cap, I've since put a electric pump, and a return line on my tank, but I left it vented at the cap.
     
  6. biggrass

    biggrass Veteran Member

    342
    0
    Aug 30, 2006
    GURNEE, IL
    Any suggestions on new vented cap?
     
  7. biggrass

    biggrass Veteran Member

    342
    0
    Aug 30, 2006
    GURNEE, IL
    Thanks Laine I see you're in N.Ill go to any cruise nights near Gurnee or the surrounding area?
     
  8. giggity

    giggity Veteran Member

    674
    12
    Mar 18, 2013
    Pearland, texas
  9. Printstron

    Printstron Veteran Member Lifetime Gold Member

    122
    3
    Mar 16, 2010
    Bakersfield, California
    If I use a vented cap and plug the vent line on my Tanks Inc tank will I still get a fuel smell from it venting in the garage?

    Edit:

    I had an idea of running a line from the vent port on the tank to one of the 3 inlets on the vapor separator behind the rear seat. Plugging the other two inlets. Then putting a small fuel filter on the remaining outlet from the separator.

    Anyone see any issue with this?
     
    Last edited: Feb 9, 2018
  10. Lou6t4gto

    Lou6t4gto Veteran Member

    258
    8
    Aug 18, 2010
    Ocala, Fla
    Thats the problem I have, the "smell of gas in the garage after I pull in and shut it down". Can I just leave the 1 vent from the tank, to the charcoal canister in the engine comp and cap whats in the trunk and all the rest ???
     

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