A return fuel line to the gas tank

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Model T Ford Forum: Forum 2016: A return fuel line to the gas tank
Top of pagePrevious messageNext messageBottom of page Link to this message  By WilliamThomas Forsythe on Sunday, June 12, 2016 - 04:21 pm:

A return fuel line: 061216

In an effort to safely run with modern traffic, a few years ago I installed a set of Model B intake/exhaust manifolds and the recommended Zenith II carburetor on the original block of our 1912 Touring. Because of the higher location of the Zenith, I was obliged to mount an electric fuel pump adjacent to the sediment bowl beneath the fuel tank. This system works quite well. However on hot summer Sunday afternoons, returning to the city across the long Jacques-Cartier bridge, followed by many red traffic lights, in bumper to bumper traffic, the pump could be heard racing “flat-out”. Through the glass body of the fuel filter, we could easily see it was trying to pump gasoline vapour rather than liquid fuel. The only solution was to pull out of the traffic, and let the system cool down.

Just recently I mentioned this annoyance to a fellow old car enthusiast, who recommended I install “a return fuel line to profit from the cool gasoline in the fuel tank”. It was in this manner that, years ago he resolved the problem of vapour lock on his beautiful ‘41 Ford Convertible.
Last week, I proceeded with just such an upgrade.
The electric pump now pushes the cool gasoline continually from the tank to the small “distribution block” then into the carburetor as controlled by the carburetor float in the normal fashion. The excess fuel continues back through the return line into the tank in an uninterrupted flow. The end of the ¼ “diameter steel brake line used as the fuel return line was plugged and drilled with a 1/16” diameter hole.(The electric pump I had chosen, operates at 3 lbs. pressure.) In the first photo you can see the small junction block securely supported with a bracket off of the intake manifold. In the second “you can actually see the flow of fuel returning into the tank!”
Yesterday during a 150 mile run at 45, 50 and even a short period at 55 miles per hour, there was no fuel shortage to the carburetor. When we stopped at our picnic destination, under the hood was as expected,quite warm, but both the fuel lines into the “distribution block” were indeed cool to the touch! This upgrade is not required on the majority of Model T Ford’s, but it has solved the problem of overheated fuel for our machine.
fuel junction blockfuel returning into tank


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Sunday, June 12, 2016 - 04:35 pm:

OT, but my 1971 Plymouth GTX came from the factory with a fuel return system. There is a special canister that looks like a fuel filter (it does have a mesh screen inside it). Fuel from the tank goes to the fuel pump (blue line). From the pump, the fuel/vapor mix goes to the canister (white line). The fuel feed to the carb (brown line) picks up liquid fuel from the bottom of the canister. Fuel liquid/vapor is picked up from the top of the canister and returned to the fuel tank via the return line (green).

pic

(Message edited by cudaman on June 12, 2016)

(Message edited by cudaman on June 12, 2016)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Sunday, June 12, 2016 - 04:39 pm:

Neat! Great idea.
2 things; 1.5-2 pounds pressure should be enough and what is all that "stuff" in the gas tank? :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By WilliamThomas Forsythe on Sunday, June 12, 2016 - 05:46 pm:

I chose a small aviation fuel pump as used on experimental aircraft - my previous passion. As to the "stuff" in the gas tank, I was surprised to see this myself. I believe it to be an optical -"photographic illusion"! Quite frankly, when I drained the fuel completely, and pushed fresh air into the tank for a household vacuum cleaner for 1/2 an hour "to remove all the remaining vapors"- prior to drilling a hole in the tank for the new return line, I clearly viewed "a very clean interior surface!" Perhaps it is simply the light from the photo flash reflecting off of the galvanized interior surface of the tank. Still I agree it looks a mess. Tom


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Sunday, June 12, 2016 - 07:42 pm:

:-) I was thinking you dumped your pipe tobacco in there.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Sunday, June 12, 2016 - 07:53 pm:

Interesting idea!!
Question though, where is your electric fuel pump located?

I drive a '81 F150 and have experienced problems on really hot days with the AC on that resembles vapour lock which I attribute to ethanol blended gas. As it has dual tanks, a return line gets more complicated. For now I try to avoid ethanol or just turn off the AC sitting at lights


Top of pagePrevious messageNext messageBottom of page Link to this message  By WilliamThomas Forsythe on Sunday, June 12, 2016 - 09:24 pm:

Hi Les: As I mentioned initially, "the pump is located adjacent to the sediment bowl,beneath the fuel tank." I also installed an electric solenoid shut-off valve between the pump and the sediment bowl. It does an excellent job of turning off the gas without crawling under the car! I only use the sediment bowl shut-off for extra insurance during indoor winter storage. Tom


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