gas tank return lines

I installed a second tank in the rear of my my 70 CJ-5. I did a search for a fuel selector switch, and ordered the one from James Duff, that Posimoto and BKD used. My question is, what do you do with the return lines? This valve is only a 3 port valve and has no place for the return lines.
Rob

 

you'll need a valve that has ports for the return lines.
or....block off the return line at the pump.

 

You might check a junkyard for dual tanked vans. Our 1990 Ford Van has dual tanks, and they have a switch that routes the pressure and return lines.

 

Pollak makes aftermarket valves that will handle two tanks with both pressure and return. http://pollak.thomasnet.com/Asset/IS-41_b.pdf

This thread has some good info. http://www.67-72chevytrucks.com/vboard/showthread.php?t=379708
Discussion here is for EFI systems, but I would expect it to work for mechanical pumps too.

 

If you are using vented caps on both tanks then you don't need to run the return line back. Just block it off at the pump as previously said.

 

A friend of mine had the same situation with his '70 Renegade. He used two of the sswitches that you bought. One for the fuel out and one for the return line. They're mounted next to each other and share the same dash switch. That's what I'm planning to do on my setup as the FI unit I'm using requires a return line to the tanks.

 

I've used those brass valves in the past. Today, I'd buy one of the Pollak valves. My J20 has an aux tank with this setup, and it works fine. You can switch the gas gauge and the valve from the same toggle switch.

Today, I think you can buy the Pollak electric valve for the same price, or less, than two of the brass manual valves. The SMP PN listed in the thread I linked is available at RockAuto for $43. You'd have to add a switch and some wiring, but I expect it will turn out about the same price as the brass manual valves.

May not ultimately be as reliable as the manual valve setup, but it will give you a lot more freedom wrt location of the valve. And clearly more convenient...

 

valve for a 1980 k20 with dual tanks has the return lines. I think i still have the wiring harness off of mine, it swaps tanks return lines and the gauge all in the flick of a a switch, pretty simple switch and valve

 

If you want a mechanical switching valve you can use this-
http://www.groco.net/
not cheap though...

BTW I'm just running a t-fitting in my return line, but sometimes it'll cause the front tank to overflow.

 

Thanks guys!
Rob