This is an on-going project. I have replaced Ford's FDR with a BWD selector valve. The first valve failed and dumped fuel from the rear tank. Replaced the valve and added check valves to the supply lines into the selector valve. So far, it is working.

The filler necks on these years have a separate 3/4 inch vent hose from the tank to the top of the filler neck. Would it be possible to tee into the vent hoses and connect them together? If one tank were to start overfilling the other tank, the excess would flow through the connected vent hoses and return to the original tank without spilling fuel.

Has anyone ever done this? Is it worth doing?

Thanks
jim

 

Noooo but, I like your thinking. It seems it would work. Myself, I'm not smart enough to come up with anything but putting back original parts.

 

I gotta think if a vent line mounted that high on the filler neck is tee'd it won't be all that useful for an over flow situation.

It strikes me such a system would be better if installed somewhere near the highest point on the tank(s) themselves effectively making them one single tank. If one were "overfilled" while the other contained a lesser amount the extra fuel would have an easier path to follow.

The vent tubes should serve a single purpose in order to be their most effective. All this is strictly IMHO of course.

 

I took the plunge and finished the project yesterday.
I did try to think of various connection points: at the tanks, at the filler neck, or even a separate connection added to the tanks.

I kept returning to the problem that I had when the selector valve failed and one pump filled the tank through the other pump. The tank pumps are 12 PSI and feed a 90 PSI inline pump to the fuel rail. The pressure valve on the gas cap is about 2 PSI so once the running pump overfills the other tank, there is enough pressure to push past the valve and pour fuel on the ground (happened during my annual inspection, what are those odds?).

I believe the 3/4 inch hose is large enough to handle anything the in-tank pumps can supply so if the overflow just drains back into the original tank that should be OK.

The connection at the top of the filler neck will only see fuel if the tank overflows so the vent hose connects mostly stay dry. It was also tons easier to get the connection made without dropping the tanks.