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Trunk Mounted fuel tank

Discussion in 'The Hokey Ass Message Board' started by north coast greaser, May 31, 2013.

  1. is it 'safe' to mount a fuel tank in a trunk of a car??

    the original tank is in rough shape (all rusted and gummed up) for my '48 Starlight coupe and i was thinking of bolting a poly round tank from speedway motors in the trunk since nobody re-pops tanks for this car. would there me an issue with venting and such?

    someone cautioned me from doing this, although they couldnt be certain that it was a bad idea since he had never done this himself.

    what are your thoughts? would this be a safe thing to do?
  2. Been done a billion times, you just need to make sure,,,, damn sure,,,, I mean really damn sure, NO fumes are seeping into the drivers compartment. I usually build a steel firewall behind the back seat, or an enclosed "box" for the tank that vents out of the car.
    Joined: Jun 1, 2006
    Posts: 1,590


    Also make sure you vent the fumes from the filler to the outside of the trunk so that the vapors do not build up inside the trunk. Very important especially if you have electronics in your trunk. I have seen so many not done and It really is scary of what can happen to these really nice cars should the vapors ignite.
  4. Use a non-vented cap and run a vent line (brakeline) out the filler neck, through the floor...


    (photo from tugmaster)

  5. Have a look at for more options for tanks, fittings etc.
  6. Model A Nut
    Joined: Mar 30, 2007
    Posts: 65

    Model A Nut

    Grand idea Big A. I like that. Now I got an idea for my Coupe build. But for sure never leave areas for fumes to gather in the trunk or drivers compartment...............
  7. R Frederick
    Joined: Mar 30, 2009
    Posts: 2,658

    R Frederick
    from illinois

    The 60's Mustangs had a tank that was mounted to the floor of the trunk and acted as part of the trunk floor, such as the one pictured above.
  8. 47ragtop
    Joined: Feb 8, 2007
    Posts: 664


    Don't do it. Yes the Mustang tank is mounted in the car but with one HUGE difference--- the fill pipe is outside the car. No matter how careful you are you will sometimes spill some gas in the trunk and you will also get fumes when you pop the cap ( no pun intended ). I had an inside fill pipe mounted with the stock tank in one of my forty Fords and I know I would Never do that again not only for safety but the smell and fumes problems.
  9. '51 Norm
    Joined: Dec 6, 2010
    Posts: 763

    '51 Norm
    from colorado

    Lots of old pick up trucks had the tank mounted behind the seat. They all had the filler and vent outside.

    If the rubber hose between the filler and the tank rots things can get really interesting, like gasoline sloshing around your feet.
  10. BJR
    Joined: Mar 11, 2005
    Posts: 7,611


    I was in a 69 Mustang that got rear ended with one of those gas tanks that was the trunk floor. The car burned to the windshield posts as the interior filled with gas from the top of the tank bursting. Seems some bean counter at Ford figured out that they could save $3.50 per car doing that, and it was cheaper to pay off the few people that got burned then to put in a trunk floor. Another better idea from Ford. From someone who almost got killed, don't do it. It's all safe until something bad happens. Yes lots of people will say they have a Mustang tank in their trunk and driven thousands of miles in it with no problem. Good for them, I wish them the best of luck and hope they never get rear ended. I won't ride in a car with one. Just my 2 cents worth.
  11. Seriously? Like a few thousand other shoebox owners I put a Mustang tank in my shoebox. Same location as stock. Where would you suggest is a safer spot for it?
  12. cavman
    Joined: Mar 23, 2005
    Posts: 659


    I once bought a 32 5 w, that had an old aircraft tank in the trunk, (OD, with many rivets that leaked) the po tried to seal it from the outside with fiberglass epoxy, it didn't work. the tank was bad........the gas seeped under the seat, ruined the carpet, and soaked into the wooden seat frame. Needless to say it got changed, it now has a tank from a pontoon that now has it's filler on the outside. The other thing I forgot to mention, was the PO smoked, and the battery, also unvented, was right next to the tank. The battery cables ran through the trunk floor, without any grommets. He drove it for 30 years like this.....I won't.
  13. flynbrian48
    Joined: Mar 10, 2008
    Posts: 7,423


    I get why people think it's cool to put a fuel cell in the trunk, because that's the way race cars are. As pointed out though, unless you've got a SEALED firewall between the trunk and passenger compartment, all the above horrible examples are likely to happen. Why not do it right? Get your tank cleaned and sealed, or scrounge U-Pick yards and find that'll fit under the floor, where it belongs.

    Just because it's easy and cheap to cobble a fuel cell in the trunk, doesn't mean it's a good idea.

  14. Fenders
    Joined: Sep 8, 2007
    Posts: 3,921


    Attached Files:

  15. well i went the mustang tank route - just got the tank from another Hamber that couldnt use it in her car. i figured that since there are a gazillion 'stangs among countless other cars still running tanks this way in the trunk i'll be fine.

    i may attempt to run a filler neck from the stock 'stang tank to my car's factory filler door on the left rear fender....would this make the filler neck too long?

    Big A - what are the details on how you affixed the brake line (vent tube) to the neck? did you drill and thread the neck or ??

  16. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547


    you can , when we build race cars we put a mandated steel ( .024 or 24 gauge ) or aluminum firewall ( .032 ) between the trunk and passenger compartment and vent the tank outside , with a poly tank remember to ground it to the body to keep it from forming a static charge as that can cause a fire issue when refueling .
  17. Stimpy- you mentioned grounding the tank to the body ... would the bolts that hold the tank to the trunk pan be sufficient for a ground? or is there another way i should go about grounding the tank?

    also, i will need to run new fuel line ... any recommendations regarding this?
  18. HamD
    Joined: Mar 3, 2011
    Posts: 298


    I just fixed an evaporative system leak (that you could barely see) on an OT steel 5/16" line underhood. That alone caused fumes from underhood you could smell. That's one good reason to skip this idea. Why not take the tank and get a reasonable facsimile made up?
  19. I think he was referring to a poly tank/fuel cell for grounding.
  20. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547


    on most poly tanks there is a seperate ground stud on the tank to attach a wire to ground it to the chassis even when bolted down in brackets , with anything flammable make a redundent set up just in case , also I couldn't tell if there is a rubber insulator between the brackets and the tank , if htere is the brackets will not be the ground , you will have to take a small 14 gauge multi strand copper wire , unsheath about 2 feet of it it and place it between the tank and the rubber then attach it to the chassis/body, this should wick off any static . I would ask speedway if there is a provision for a ground stud on the tank , the pipe connections won't do because of the pipe sealer people use
  21. Pete1
    Joined: Aug 23, 2004
    Posts: 2,091

    from Wa.

    Besides all that, if you have a metal filler cap assembly that is seperated from the tank itself
    by a piece of neoprene hose, you should attach a ground wire to the cap assembly.
    Bleeds off static when filling. Always keep the hose nozzle or funnel in contact with the cap assembly when filling.
  22. wow, thanks for all the feedback guys!! this is all useful info for me as this is the first tank i've had to do.

    the mustang tank i will be using is an all metal re-popped version of the 64-68 (?) fuel tank and i will be installing it in my studebaker the same way that it was meant to be mounted in the mustang it was originally designed for. will there still be a need to ground the tank?

    are there any pics of how you guys have grounded tanks and grounded the filler cap?

    im an artist so im pretty visual and pics would help a lot!

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