New Fuel Tank Install Issue: 72 Plymouth Scamp

Discussion in 'Fuel and Air Systems' started by 7milesout, May 21, 2018.

  1. 7milesout

    7milesout Well-Known Member

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    Guys -

    I've been collecting a lot of rusty stuff in the carb float bowl. And had another issue just recently of the AFR going lean after about a 10 second full-throttle acceleration. I thought I might pull the tank and have it cleaned. But in checking around, cleaning the tank was pretty close to the same cost as a new one from Summit.

    So I bought a new one. The neck moved out of the way rather easily. The new tank fit in place rather nicely. I'm really only having one issue.

    Issue: The original filler neck does not fit to the new tank in the same way as the original.

    The original condition: The filler neck and tank were probably 0.002" to 0.005 difference. I say that because the filler neck slid backward out of the tank rather easily after detaching the seal from the trunk floor. And since the filler neck and gas tank were not likely in perfect alignment (but certainly aligned well), there had to be some gap to make the neck fit into the tank. I would guess, if I checked side to side slop neck to tank, it would have been little to nearly none.

    The new condition: The hole opening in the new tank is larger than the old. Based on this, I would think that the neck may rattle in the hole and maybe gas might spill out.

    Questions:
    • Is gap normal?
    • Would there be rattling noise and/or spillage?
    • Is there not a gasket that should be installed around the filler neck and protrude into the tank to seal and stop the rattling?
    Thanks!


    7milesout
     
  2. 7milesout

    7milesout Well-Known Member

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    On 2nd thought, the original fuel neck filler seal (mounted on the inside trunk floor) is likely to keep the filler neck braced at the tank. So that would stop the rattling.

    But, with the gap that's there between the filler neck and tank, seems fuel might slosh out somewhat ... when the tank is full. The above question about needing a gasket, remains.

    Thanks.


    7milesout
     
  3. cannucky

    cannucky The Guy With No Birthday

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    yes there should have been a donut gasket in the old tank the trunk rubber is for fumes , use a little white grease to slip the filler neck through it .
     
  4. 7milesout

    7milesout Well-Known Member

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    Weren't no donut gasket to be found. Maybe it went for a happy meal years ago and lost its way home? Or maybe it's in the tank. I'll light a candle and hold it down in the tank and see if the gasket is there.

    On another note, previously if I filled the tank full enough, I would smell gas until I drove it a bit. Must have been leaking around the filler neck due to the lack of an o-ring / donut gasket.
     
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    • replicaracer43

      replicaracer43 Old school member

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      Yes, you need the filler neck donut
       
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      • 72Dart6pack

        72Dart6pack Harder Better Faster Stronger.

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        Have your insurance paid up before you light that candle. :)
         
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        • 7milesout

          7milesout Well-Known Member

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          :rofl:
          If I don't follow up, be concerned.
           
        • cannucky

          cannucky The Guy With No Birthday

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          Congratulations here's your Darwin Award .
           
        • j par

          j par Well-hung Member

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          Or maybe he can fill it up with 14.7 to 1 fuel to air?
           
        • 7milesout

          7milesout Well-Known Member

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          If I did that, I could bypass the carb, and just run the fuel line right into the intake!
           
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          • 7milesout

            7milesout Well-Known Member

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            I'm still alive, but did not find a donut in the tank. So I'm going to take my calipers home and measure the Tanks Inc inlet port. Based on that I'll buy one of Tank Inc's, Universal Neck Grommets. Either a GR4 or a GR2. I'm guessing a GR4.

            Does anyone want a free gas tank? Comes with a free gallon of gas!


            7milesout
             
          • 7milesout

            7milesout Well-Known Member

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            I received an o-ring this Saturday and put it all back together on Sunday. I had a gas can with about 2.5 gallons of 90 octane no ethanol, so I added that to the new tank. The carb was EMPTY because I cleaned it up, it had had some rusty crap in it from the tank. I also replaced the fuel filter mounted just prior to the carb.

            The car fired up much quicker than I was expecting. 10 seconds of cranking, nothing. Was going to do another 10 seconds but it hit at about 5 seconds and fired up right after that. I took it to the gas station and finished filling it up.

            I notice now that the, just off idle lean spike is gone. Usually about 1 to 1.5 seconds after a casual start from a stop, it has a hesitation. I have always been able to see that hesitation on my AFR gauge as a lean spike. A drag type of launch never has this issue. Just only a slow patient start off. But now, that seems to be gone. It rolls out very nice. No hesitation.

            The car is running good. I did a couple hard launches after it was fully warmed up and running great.

            However, now I have a new issue. :( See this thread: The green Scamp is feeling blue...