Fuel tank idea

[rthomas]

Posting here because the crickets upstairs are pretty loud. Im replacing the rear tank in my psd because its leaking, and I made the observation that the front tank is 4" +- lower than the rear, with that in mind and gravity what it is could (or has) someone welded fittings on the tanks to connect them together? For sure you would want valves at both ends and perhaps a check valve to keep fuel from running back to the rear while parked on a steep hill. The advantage I see to this is being able to use all of the fuel in one tank and eliminating the need for a switching valve.

 

[franklin2]

Filling the rear tank too much may overfill the front tank. An idea that has been tried with some success is using a small electric pump to transfer fuel from the rear tank to the front tank. Of course this takes some supervision(watching the gauges) so you do not overfill using this method also. But doing this eliminates the valve and the return lines to the rear tank, and makes it a aux tank instead.

 

[MIDNIGHT RIDER]

Posting here because the crickets upstairs are pretty loud. Im replacing the rear tank in my psd because its leaking, and I made the observation that the front tank is 4" +- lower than the rear, with that in mind and gravity what it is could (or has) someone welded fittings on the tanks to connect them together? For sure you would want valves at both ends and perhaps a check valve to keep fuel from running back to the rear while parked on a steep hill. The advantage I see to this is being able to use all of the fuel in one tank and eliminating the need for a switching valve.

What you describe is pretty much how saddle-tanks are plumbed on big trucks.

The engine draws from only one tank.

That one tank has the sending-unit for the gauge.

If the truck is used in not-so-level terrain, a cut-off valve is closed between the two tanks to keep fuel from the higher tank from over-filling the lower tank.

Once the gauge shows 1/2-tank or less, the valve is opened to allow the levels between the tanks to equalize.

Many over-the-road drivers never have reason to use the valve between tanks as they are always on mostly level pavement.



In your situation, I would install a cut-off valve at the bottom fitting of both tanks for emergency uses.

I would route the line between tanks such that a third cut-off valve would be located where I could access it without crawling under the truck.

This could be accomplished either by routing the line to a point accessible from beside the truck, or by using a long-stem valve that is accessible via a trap-door in the flat-bed.


Close the valve and fill both tanks; run until the DRAW tank is below 1/2; then, open the valve and continue until the next re-fill.

 

[MIDNIGHT RIDER]

As for the fittings in the tank's bottom, instead of welding into such thin metal, where stress-cracks and vibration-fatigue is going to cause leaks, use JIC bulk-head fittings instead.

These bulk-head fittings have an inner and outer O-ring seal.

The fitting is installed through the hole from INSIDE the tank and a nut secures it from OUTSIDE, squeezing and sealing the O-rings to provide a secure seal.

It is a simple matter to route the INSIDE fitting by working through the big gauge-sender hole.