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timtechcorvairwiki:09_fuelandexhaust_systems:electric_fuel_pump_for_the_corvair

Electric Fuel Pump for the Corvair

By Blake and Tim Palmer

Diagram A.

As most of you are aware, the stock Corvair fuel pump is not as readily available as it used to be, and more importantly, it has a reputation for poor reliability. The Chevrolet Vega used an electric fuel pump mounted to the pick-up tube, inside the fuel tank.. This unit is readily available and easily adapted for use on the Corvair. The conversion described in this article is for a '61-'64 style tank setup, but this conversion should be possible on any '61-'69 Corvair car or wagon, since they all use the same fuel tank. I'm not certain as to its compatibility with the '60 style fuel tank. Since your old Corvair probably still has the original sending unit in place, the first step is to go ahead and obtain a new one to replace it. A new unit will be easier to work with and also will allow you to scrounge necessary parts from the old unit for use in the conversion. (Use GM P/N #6428062 for '61-'64 cars, or #6428063 for '65-'69 cars, or check with various Corvair vendors.) Next, obtain a Vega fuel pump. I bought mine from the neighborhood parts store without shopping around and it cost about $27. The pick-up tube of the stock sending unit must be modified in order to mount the Vega pump. The tube must be cut to length and bent so that the pump will clear the float and also rest on the bottom of the tank. The easiest way to accomplish this is to make a mock-up of the installation using an old fuel tank from a parts car. Cut the top off of the tank, being sure to use proper safety precautions (i.e. proper ventilation: make sure that no fumes are left in the tank). Now you can view the assembly inside the tank in its installed position.

Simplified, here's a breakdown of the modifications to the pick-up tube. First, remove the stock filter screen from the pick-up tube. The pick-up tube must be cut off to position the pump properly. The exact length is not critical, just leave enough tube for the pump to be coupled to after the bend you are about to make (see diagram A). The Vega pump installs by simply slipping its coupling hose over the pick-up tube and securing with clamps. The pump I purchased did not come supplied with clamps, but the thought of the pump coming loose in the tank makes me want to be sure that the pump is secure. In order for the pump to clear the float, the pick-up tube must be bent about 45 degrees to the left (as viewed from above its installed position, see diagram A). Now the tube must be bent down to position the pump on the floor of the tank. The Vega pump has a built in rubber bumper which is meant to rest against the floor. The proper positioning of the pump is a trial and error process which is much easier with the use of the mock-up mentioned earlier. Now that you have the assembly physically prepared for installation, you must prepare a way to get electricity to the pump.

Diagram B.
You will need to remove the insulated connector for the wire to the gauge from your old sending unit. This will be installed in addition to the connector already present on the new sending unit in order to get power to the pump. The most obvious place to add the connector is on the boss opposite the stock connector on the sending unit. It looks like it was made just for this purpose. However, after installing the connector in this position, we discovered that you can't attach the plug to the connector due to the position of the fuel outlet tube. So, there are two alternatives: bend the outlet tube so that the plug can be attached, or locate the connector so that it does not interfere with the outlet tube. Since the connector was already installed, we bent the outlet tube to clear the plug. There was no problem attaching the fuel lines going back to the engine compartment; make sure that they are all in good condition and that all clamps are tight. With the fuel pump now in the tank, the lines are pressurized all the way to the tank, not just in the engine compartment, as was original. Okay, back up front, this new connector will be connected to the positive terminal of the new pump via a jumper you must fabricate. At the other end, it will be connected to a power supply. On my car, I used a sending unit plug and wire from a parts car to get a matching connector. This wire will be run up under the dash and hooked up to a switched power source, such as the radio terminal. It is critical that you use a power source which turns off with the ignition. Otherwise, the fuel pump will not shut off - definitely not desirable. The negative terminal of the pump is connected by a jumper to the bracket of the pick-up tube so that it will ground (see diagram B).

In the engine compartment, the fuel lines will have to be rerouted to bypass the stock fuel pump. You will have to buy, beg, borrow, or steal a flare fitting set, tubing bender, and tubing cutter for this purpose. Your local parts store should stock steel brake line to use for the new lines. The fuel lines can be set up many different ways. This is up to you. One of the diagrams shows one possible layout. It is recommended that you not use rubber fuel hose to make new lines. Corvairs have very high temperatures in the engine compartment and rubber doesn't survive well in this environment. Besides, steel lines look much nicer and really aren't that hard to make.

The stock fuel pump hole is replaced with a plug which is available from Clark's for about $5.

The two lines which go from the “tee' to the carbs can be retained if desired. You can use an elbow fitting at the “tee” and either re-bend the stock inlet line or start fresh and make a new inlet line. The next paragraph will probably necessitate making a new line, anyway.

I have found it is necessary to use a fuel pressure regulator with this fuel pump. Since it runs continuously no matter what the engine is doing, there is a tendency to flood at idle. I used one of the adjustable regulators which are readily available for about $15. Using pipe thread-to-flare-fitting adapters, this unit can be connected directly to the steel lines for a very tidy installation. The regulator can be located anywhere you choose as long as it's before the “tee' (unless you want to buy two regulators). It should be noted that all references to line configurations in this article refer to a two-carb Corvair engine. All other applications will require different approaches. As far as the pressure setting goes, my 102 HP engine only requires 1 1/2 p.s.i. for proper operation. I have experienced no starvation problems under any conditions.

This set up has performed flawlessly to date. The pump operates very quietly. The only time I can hear it is if I listen for it when I turn on the ignition before starting the engine (I find its low hum reassuring). The electric fuel pump can aid heat soak problems, as well. Since it starts pumping before the engine is running, it will feed fresh fuel into the carbs to replace vaporized fuel in the lines (refer to tech articles concerning vapor lock).

If you plan ahead, the conversion can easily be done in a day and will add a lot to your Corvair's reliability. Good luck.

Editors Note: Since the fuel tank must be drained for this installation, extreme care must be used during the draining process. Do not use incandescent lights while service is performed on the fuel system, as any fuel splashed on the bulb may be ignited.

timtechcorvairwiki/09_fuelandexhaust_systems/electric_fuel_pump_for_the_corvair.txt · Last modified: 2015/01/13 17:05 (external edit)