One of the most difficult tasks of fuel-injection retrofit is gettingthe excess fuel returned to the fuel tank. A fuel return must beprovided in the fuel-tank sending unit for proper fuel control. Theearly sending units are small in diameter, which makes it difficult tohang on the retrofit fuel pump and wiring. The fuel should return to thebottom of the tank to avoid dangerous static-electricity buildup. Earlytanks didn't have baffles, which can be detrimental to the fuel pump ifit runs dry during hard acceleration or cornering. The smart choice is acustom-built fuel tank.
Every retrofit requires a fuel-return line, which is another concern.Some of the later Corvettes are equipped with one, but unfortunatelyit's only 1/4 inch in diameter. A 5/16-inch return line is necessary ifthe supply line is 3/8 inch. Higher-horsepower applications requirelarger-diameter fuel-supply and return lines. With regard to the fuelline, replacement of the original 3/8-inch supply line is a good ideawhen installing the return line. It's best to use as much steel line aspossible with the fewest fittings to ensure a safe, pressurized fuelsystem.
The fuel-injection pressurized system (at 45 psi) is like amini-flamethrower if a fire starts. The fuel lines and hoses live in ahostile environment most of their lives. When ordering, check all hosesfor fuel compatibility and pressure ratings. Some of the new fittingsand hoses don't require clamps because they are pushed on and havebarbed fittings that grab the hose.
In a previous issue, we discussed the possibilities of a fuel-tankreplacement on Keisler's Project Maximum Overdrive Ram-Jet fuel-injected'65 Corvette. We decided on the Rick's Hot Rod stainless steel tank.
Hector at RHR had the blueprints for the tank and had assembled a few.We discussed our needs with him, and he made our decision easy: RHRwould build the tank.
The fuel tank was fabricated and welded with quality craftsmanship. Bestof all, it fit without any modifications. RHR uses a universalfuel-level sending unit with the OHM resistance necessary for correctfuel-gauge operation. They install an ACDelco fuel pump in acustom-built housing to contain the required wiring and fuel-lineconnections. The tank installation was simple, but plumbing the fuellines and hoses was a bit more difficult.
The RHR fuel tank made the retrofit easier and added a reliable fuelsystem with easily maintained components. RHR incorporated a bafflearound the fuel-pump pickup area to avoid fuel starvation on hardlaunches. The fuel tank is a home run in all respects.
We had the body off because the 3/8-inch fuel-supply line that's routedthrough the frame in the rear had considerable internal rust. Removingthe body is a lot of work, but trying to install an additional 5/16-inchfuel-return line is difficult on the '63-'67 cars. These are realconcerns before starting the installation, so plan accordingly if youare in the process of fuel-injection retrofit.
The fuel tank is ready for...
The fuel tank is ready for installation of the fuel-level sending unitand fuel-pump assembly. RHR had previously fabricated convertible tanksand modified the tank to accommodate the OE coupe filler tube. Themid-year coupe rear deck has a pronounced angle, requiring a longer filltube than the convertible. This is why some photos show a differentfiller tube.
As you can see, the fuel tank...
As you can see, the fuel tank fits well. The fuel-level sending unit ison the left side with a fuel-vapor vent hose. The right side is wherethe fuel-pump housing is installed in the tank. We use the factory fuelfiller tube extension to place the fill tube in the correct location.
The factory straps are used...
The factory straps are used to retain the fuel tank. The soft side of aVelcro strip is used to line the underside of the tank strap to preventwear. The fuel supply and return fittings are steel along with thepush-connect fittings. Use a hose to connect the fuel tank to the steelline. A direct coupling to the tank with steel lines creates noise andpossible cracking of the lines or fittings due to movement.
Steel lines are used from...
Steel lines are used from front to rear. The hose connections and lengthof hose are made like this to allow servicing later if necessary. Thehoses can be removed from the lines at the frame, slipped out of theclamp, then lowered with the tank. Hoses left against the body can causerumbling noises and hose wear. These hoses are high-pressure-rated fuelcompatible. Stainless braided hoses are used at the engine side forprotection from heat and outer hose-cover damage.
This represents the fuel lines...
This represents the fuel lines we used. This line connects thefuel-injection rail at the engine to the flex hose coming off the frame.The flare fittings are 45-degree, allowing direct connection to a flexhose. Silver solder is used to install the fittings on the steel line.