Re: extra fuel vent lines
Posted by HH56 On 2014/6/14 16:20:01
That looks like a rotary pump and if I had to take a guess, the return line would be there for one of two reasons. One would be the pump has too much flow or pressure for a regular carb and the return line is there to let the excess flow somewhere without stressing the pump or flooding the carb.. Two would be the return line might have been a way to reduce vapor lock. Modern cars use a similar setup only the pump is in the tank. With the return line and fuel continually flowing, there would always be cool fuel available -- at least at the tie point near the pump.
Without knowing the specs of the pump, I would be hesitant to just say get rid of the return. Quite honestly, if it were my car I would get rid of the entire setup and just get a small pulse type pump. Do as most do and go in series with the mechanical and let the mechanical pull thru the electric pump. Equip it with an on/off switch under the dash and single fuel line. Run the pump only for priming or emergency.
If you do want to keep parallel lines so the electric doesn't push thru the mechanical then you would need to keep the tee at the fuel pump outlet, get rid of the return at both ends but add a similar tee arrangement at the tank outlet for the second feed and then run the parallel line back to the engine fuel pump outlet tee. There should be no need for a check valve with the pulse pump but you could keep it if you wanted to.
Here is what I did with mine. Not finished yet because the area is still under construction but pump is in the final location on the frame cross piece just behind the spare tire well. You can get an idea of the mounting position from the photo. When tank is in, short line from the tank outlet will go up and to the left to enter the pump filter. Did similar with my 56. Seems to work well and being high pump is somewhat protected.
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Without knowing the specs of the pump, I would be hesitant to just say get rid of the return. Quite honestly, if it were my car I would get rid of the entire setup and just get a small pulse type pump. Do as most do and go in series with the mechanical and let the mechanical pull thru the electric pump. Equip it with an on/off switch under the dash and single fuel line. Run the pump only for priming or emergency.
If you do want to keep parallel lines so the electric doesn't push thru the mechanical then you would need to keep the tee at the fuel pump outlet, get rid of the return at both ends but add a similar tee arrangement at the tank outlet for the second feed and then run the parallel line back to the engine fuel pump outlet tee. There should be no need for a check valve with the pulse pump but you could keep it if you wanted to.
Here is what I did with mine. Not finished yet because the area is still under construction but pump is in the final location on the frame cross piece just behind the spare tire well. You can get an idea of the mounting position from the photo. When tank is in, short line from the tank outlet will go up and to the left to enter the pump filter. Did similar with my 56. Seems to work well and being high pump is somewhat protected.
Attach file:
(99.13 KB)
(94.50 KB)
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