It all started because I was having a fuel problem. After driving the Valiant for any extended period of time, it would act like it was running out of fuel. When I was finally able to get the time to look at it, I found that the stock mechanical fuel pump was heat sinking (absorbing the heat from the engine), and vaporlocking.
There are a couple of different ways to remedy this situation. One would be to plumb a return line from the pump to the fuel tank, giving the pump a constant flow of circulated fuel. Since the fuel would be in continuous cycles from the tank to the pump and back to the tank, it would effectively help keep the fuel pump cooler. Another idea is to remove the pump from the engine. To do this requires installing an electric pump in the system.
An electric pump is designed to be more efficient if it is installed in a location as close to the tank as possible. The reason for this is to "push" the fuel to the carburetor, as opposed to being mounted near the engine and "pulling" the fuel from the tank. Knowing that the Valiant will be receiving a different engine in the future with a larger appetite for fuel, we decided to do more than simply install a pump near the tank and call it quits.
The fuel tank already in the...
The fuel tank already in the Valiant had sprung a leak, so it was definitely time to change it. Our new one from Year One fit the bill nicely. A new tank is also good insurance that no junk will contaminate your fuel system.
Fitting the universal rear-sump...
Fitting the universal rear-sump kit to any fuel tank will require welding and modifications. The Valiant has a fuel-tank strap that runs from framerail to framerail. The strap actually runs right where the sump gets welded to the tank. We would have to modify our sump to end at the strap.
We cut the sides of the sump...
We cut the sides of the sump so the bottom could be folded over and make the back of the sump where the tank strap crosses. We then welded the folded metal back to the sides. This wall at the back of the sump acts like a dam and helps keep the fuel in the sump during deceleration.
The sump kit comes with this...
The sump kit comes with this diagram to show you where to drill the 2 1/2-inch holes in the tank. If you cut the tank to the size of the sump, you take some of the rigidity of the tank away, and now there is no baffling for the sump. Just take a center punch and mark the holes, and then drill with a hole saw. We didn't need the hole closest to the front since we shortened our sump.
After the holes are drilled,...
After the holes are drilled, it's time to weld the sump to the tank. Begin by spot welding at the corners and make sure the sump placement is where it should be before you do any more welding. When you weld the sump to the tank, take your time and weld at different locations to avoid warping the tank. When you have the entire sump finally welded, you can grind the welds a little to clean them up and make the job look nicer.
After you have tested the...
After you have tested the welds to make sure there are no leaks, you can paint the tank. As added insurance, a thin coat of epoxy over the welds can be cheap insurance. Now, the sending unit will need to be removed from the old tank and put in the new one. A cap plug will need to be installed over the factory feed location.
There are two outlets in our...
There are two outlets in our sump, one gets plugged and the other will feed the pump.
It was decided that a Holley...
It was decided that a Holley "Blue" fuel pump would suffice our needs.
We mounted our pump on the...
We mounted our pump on the rear framerail, tucked up out of sight.