Hello,

We are looking for an electric Fuel Tank Selector Valve.

Thought the Pollak 42-159 would work, but found it is 6 1/4 inches from top to bottom and it is rotated about 30 degrees from its integral mount so that the inlet and outlet ports are not parallel to the mounting surface, maybe creating some fuel line routing problems. .

Thought we had seen on the Forum that some were using the Pollak tank selector valve. If so,
where are you mounting this rather large valve and in what orientation?.

We need to accommodate the higher pressure of our 45 psi fuel injection system so the regular
GMC electric fuel tank selector valve and its low pressure rating probably won't work for us.

Thanks for any suggestions,

Don and Susan Jeffers
78 Eleganza II


Thanks all for thanks for the suggestions.

But the original style low pressure selector valves are not suited for use with in tank pumps; low or high pressure.

The low pressure selector valves are designed to be placed between the tank and the pump and
are generally rated at 8 psi vacuum, not pressure. I wish the original style selector valves were suitable as they are small and compact.

Our present in-tank fuel pumps are rated at 75-80 psi pressure and pressurizing through the
original style tank selector valve in the backwards direction from design, could result in a very high pressure differential above design for the valve.

The failure mode is usually failure of the internal seals and cross-circuiting of the fuel flow. At some pressure they could leak fuel.

Our entire fuel system is high pressure.

The in-tank pumps rated at 75-80 psi (hopefully no vapor lock) and are set into a one inch sump in the bottom of the tanks. The lines off the fuel tank sending units for both delivery and return use inverted flare connections with modern high pressure flexible lines for about six inches or so transitioning to steel tubing for about another 30 inches where they are connected to more steel tubing through inverted flare fittings on up to the engine area.

Then another high pressure flex line crosses from the frame to the factory engine mounted fuel
injection fuel filter and more steel line to the fuel injection pressure regulator that holds pressure in the fuel rails to 45 psi at the injectors. The rest of the fuel goes back to the tank in the same manner via steel lines.

Our entire fuel system is designed to be robust and well suited for even more alcohol in the fuel, if the government ups the alcohol level up to 15%, as they are threatening to do.

As long as no obstructions arise in the fuel return line the pressure would be fairly low. But, given a piece of road debris such as a tire alligator hitting and crimping a fuel return line, the pressure could go up to the maximum of the pump, 75-80 psi. Also, if someone were to leave the key on and the fuel pump running with the engine off, the return line pressure could go up pretty high.

The Pollack selector valves are rated at 65 psi and are suited for the pressure requirement, but have an awkward angle on their built in mounting bracket and are handed wrong. The ports are arranged for mounting on the passenger side of the coach and our GMCs have the fuel system on the drivers side.

So with our three tank system, we would have to run two Pollack selector valves mounted upside
down (okay) with awkward line bends (not so okay) due to the Pollack valve being rotated about
30 degrees to its mount and lying on its side due to the 6 ½ inch height. .

So we were hoping someone had found an okay location to mount the long Pollacks. Or even
better, found a high pressure electric fuel selector valve more suitable for our GMCs.

We do welcome all suggestions as they lead us to think.

Thanks,

Don and Susan Jeffers
78 Eleganza II with EFI

Getting a lot of quality time together under the coach building this fuel system!


Also, if someone were to leave the key on and the fuel pump running with the engine off, the return line pressure could go up pretty high.

Good question Pete.

The fuel pumps do have non return valves and are on a common fuel delivery line. We don't
need the fuel selector valve for the fuel from the tank to the engine, but for the fuel returning to the tank from the engine.

The last stage of the three tank system we are building is to make individual fuel fill lines from three individual gas caps to the three tanks; so at that point the return fuel will need to go back to the tank it came from, requiring fuel tank selector valves.

It would have been a lot easier to use the common rail fuel delivery line, use only one common
vapor line to the existing filler neck and one common rail fuel return line to all three tanks with no fuel selector valves. Our fuel pump/sending units lines dump return fuel at the base of the in tank pumps pick up.

Three simple lines (delivery, return and vapor) would have been a lot easier but won't work with three totally separate fuel tank systems. We might go with a common fuel return line until we find suitable fuel selector valves.

Our goal is to make three totally independent fuel tank systems.

Don and Susan Jeffers
78 Eleganza II EFI

The return is low pressure.

You can use the original selector valve.

Rick M.