My take on in-tank mounted fuel pumps is this:
Ethanol laced fuel changes the equation quite a bit, relative to
longevity of electric pumps. Corrosion is a big factor when the system does
not continuously receive a fresh supply of fuel, and I personally do not
think that the positive points of having a pump mounted submerged in the
stuff outweighs the negative points of the effects of alcohol on the pumps.
I think that mounting the pumps on the frame as close as possible to the
tank outlets, and protected with in-line filters between the tank and pump,
as well as objects that might be thrown up from the road is the best long
term solution. The accumulator or surge tank downstream from the pumps is a
very good idea as well. The same goes for the tank switching valve. It is a
problem looking for a time and place to happen. The original valves fail
when subjected to alcohol in the fuel, as do the diaphrams in the original
equipment mechanical fuel pumps. Ken Burton makes valid sense with regards
to not controlling electric pumps with relays. They frequently have been
known to stick closed (allowing electricity to flow) when you want them to
open or disconnect the flow of electricity. Better to use good fuse
protection and large enough conductors and switches to operate the pumps
without relays in the circuits. A low/no oil pressure switch wired into the
pump circuits is also a good idea.
If you do decide to mount your pumps submerged in the fuel tanks, at
least provide access hatches to your tanks from above. You are probably
going to need them, in my experience.
But, as Jim Bounds often says, "Hey, this is America! It's your money,
spend it how you see fit"
Jim Hupy
Salem, OR
78 GMC ROYALE 403
> I am swapping tanks from an empty GMC to one with an interior. I redid the
> tanks about 12 years ago with POR15 and rebuilt the gauges. There is a
> nipple 3/8" about 10" from the filler and level with it an the side of the
> rear tank. The tank I took out had it plugged. Where does it go to?
> Also the front tank has no vent tube to the fuel separator, it has been
> wielded over. Should I T off the vent line (to the fuel filler) so there is
> a
> path to the fuel separator in the event that the rear is low with full
> tanks and the rear fuel separator hose is blocked with fuel?
> --
> Eric & Ree '74 ex-Sequoia + '75 Eleganza Alexandria, Ontario,
> Canada
>
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