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#1
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'65 GTO Fuel Return
I have a '65 GTO with a dead end 5/16" gas sending unit and feed line.
My mechanical fuel pump has an outlet for a ¼" fuel return line. Is there any issue with running a return line to the ¼" gas tank vent tube on the filler neck, and changing the cap to a vented cap? I ask, as there doesn't seem to be a gas tank sending unit available with a 5/16" + ¼" return nipple. The reason is tough starting due to boiling fuel in carbs after heat soak.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#2
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A/C cars have the return nipple in the sender. That sender is available through our host, plus many others.
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"I know just enough to keep me here, but not enough to get me out" |
#3
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Our host only has the sending unit with ⅜" feed and ¼" return according to their catalog and my check online. If I am wrong, would you mind sending me the part number?
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#4
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Wow! You're right.... they must have stopped making them...? I'll look around here today, I believe i have a new one around here that came with my car that i won't be using. I put a 3/8 fuel line in when i did my car.
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"I know just enough to keep me here, but not enough to get me out" |
#5
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Running a vented cap on a '65 will let gas leak out on acceleration if you have more than 1/4 tank of fuel. I would use the later sender with the 1/4 outlet. That said, boiling in the carbs after shut down won't be cured by this. Modern fuels boil at 140 degrees and are not formulated for carbureted cars. Nature of the beast these days.
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Jeff |
#6
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Thank you for that info. The vented cap is non-starter then.
I was hoping that with a return line and phenolic insulators, it would mitigate the issue substantially.
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#7
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Quote:
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#8
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Vented gas cap will cause leakage on take-off.
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Jeff |
#9
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I used the 3/8" sender with the 1/4" return
I just used 3/8" hose from the sender to the 5/16" hardline. The hardline is barbed and it will hold 3/8" rubber hose, just tightening the clamp |
#10
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I have a '64 GTO that has always had a vented cap. Car used to run 1.6x 60' times. I've never seen any evidence of fuel coming out of the cap. Please explain your experience with this. I also rarely fill much more than a half tank.
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#11
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Quote:
64's did not have this setup, as the the fill neck was up high above the bumper, and used a vented cap
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66 GTO, 495, M22, Strange S-60 w/4.10 Sold new at Ace Wilson's Royal Pontiac http://www.youtube.com/watch?v=cUHC-Z8xhtg |
#12
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Quote:
Obviously you have never seen gas actually come out of your cap/tank when you are driving the vehicle. And the Gas has probably vaporized by the time you finish your run, return to the pits, and get out of your car to look at the gas cap area. Need a watcher to confirm for you that the gas does come out of the tank and how much. AND it is a 50/50 deal on if your gas cap does leak gas. So I would say, based on my experience from early 1965 to the 2021 that it depends. Just like if a heater core fails due to a slug of water on a 1965+ engine that is beat on and not on a 64 Grandma's GTO driven on Sundays. 64 GTOs can kill heater cores too, as I have posted in several threads, or leak gas. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#13
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Interesting about the filler neck height differences. I can see how the later ones would be more likely. The '64 goes quit high and has a bend. I usually raced with a 1/4 tank. Hard to imagine it coming out. I forgot to mention that I installed a sump box in the middle of my tank. This would further dampen fuel slosh. Fuel leaves a pretty clear residue. I'm confident I would have seen evidence inside the fuel door area if this had happened. Good to learn more about this regardless. Maybe for future cars!
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#14
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65 used a vent tube on the neck. there was a hose that routed up to a u shape vent tube above the tag . there is a metal strap welded to rear body panel. the car used a NON vented cap
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#15
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Yes, I was curious if I could install a "T" off of this and run a return line to it?
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#16
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The OP has a '65. '65 and up GTO's have the fuel filler lower than a '64----it's behind the rear license plate, as opposed to having a dedicated gas door well above the rear bumper. '64's can run vented caps....'65-up's will leak.
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Jeff |
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