Trooperthorn

On my crew build, I replaced the rear cross members with those from a Ramcharger and I am putting a second tank in the frame behind the rear axle (Ramcharger tank). The rear tank will have a diesel sending unit identical to the one in the stock cdt tank in the stock location next to the frame.

I have never plumbed a dual tank system where the fuel system has a supply line as well as a return line. Also, I want the gauge and low fuel light to work when I switch from tank to tank.

Does anybody have any input? I would love links or part numbers for switches and valves. Or maybe somebody has a link to a site or a thread that steps a guy through this.

Thanks, Eric

ofcmarc

A 5 pin relay will switch your senders from tank to tank using the same gauge. All you need then is a valve for dual tanks that have returns as well.

Grainger probably has something that will work.

ofcmarc

Try this.

http://www.napaonline.com/Search/Det...198_0158649097

BearKiller

I have been running THREE tanks for many many years.

I have tried it all at one time or another.

What DOES NOT WORK for long are any of the electric tank switching valves, not even the ones that come on factory trucks.

What DOES WORK and lasts almost indefinitely are TWO manual valves; one is for DRAW and the other is RETURN.

The best easiest cheapest method for switching the gauge function from one tank to another is a plain old SPDT switch.

To maintain the "LOW FUEL" function on both tanks, you would need a DPDT switch instead, with one leg switching the gauges and the other switching the warning lights.


The best easiest spot to mount the manual valves is to mount the valves underneath the floor, with the stems/handles poking through the floor in the area between the driver's seat and door.

Bogie

Universal tank valve


Dash switch

MrExtreme

Hey BK, what kind of valves are you using, did you find some kind of multi position valve? I can't use those factory style fuel valves as I am running 1/2" fuel lines. I considered ball valves but then I would need 4 of them.

YOREL

Gooogle "3 way ball valve". might work for you.

Douglas2

hey-Hey!!!,
Get a 6.9L Diesel F250 valve( one from a dual tank OE config ). That one never gave me any issues at all...well almost, I cut its wire when I did a C6 rebuild and it quit switching 'til I spliced it back together. That one switches both return and feed. It makes a nice 'clunk' when switched you can hear.
cheers,
Douglas

griffination

What Bearkiller suggests is the most reliable route. I've done this to my own truck and love it. You don't realize how nice it is to have manual valves till you've had a few electrics die (and in my case take the truck down with em).

BearKiller

Here is where I get my valves :

https://www.flowline.net/default.asp...&itemcode=6747


They have them in 1/4-, 3/8-, and 1/2-NPT.

The 4-way valve will support three tanks plus an OFF position.

I highly recommend getting a 4-way, even if you only have two tanks, as it gives you the option of using that third port should you need it later, otherwise it can simply be plugged.

sooty

i used a napa valve like the one shown above, but i has 3 more lines on it for the return back to the tank, for the switch, i used a double pole, single throw, to isolate the tank senders, and valve power, napa has the parts from standard electric, i can dig up the numbers for the parts if you like.

BearKiller

For what it's worth, and this is my own experience on the subject:

I have never experienced any long-term success with any of the electric valves; sooner or later, they will quit, usually defaulting to NO TANK, with no warning whatsoever = not a good thing with a trailer-full of cattle in a busy intersection.

I tried several of the electrics of varying types/brands and will never use an electric valve again.

Trooperthorn

Thanks for all the input. Over the years I have heard a lot of grief stories with the electric valves, although I had one for many years on my crew with the 440 with no issues. I had been thinking of the dual manual valve set-up, but did not know if that was kosher. I was hoping there was a single manual valve that would switch both the supply and return lines, but reaching down and switching two valves would be no big deal. Especially if I am not doing it in a panic while coasting dead like I did too frequently in my carburated junk.

Thanks again.

BearKiller

They do make, and I have some in my shop, manual valves that switch both DRAW and RETURN.

These are just a double stack of the regular valves with an extra long stem that operates both.

The problem is in that overly long operating stem; were it as big around as a truck axle, it would be fine; however, being barely 1/4" diameter, it snaps in two at the least excuse.


So, that put me back to the two separate valves.