Electric Fuel Pump Question

[RKF]

Is it possible to install an electric fuel pump and keep the mechanical fuel pump in place, but remove the push-rod for the mechanical pump?

I'm thinking about doing this for two reasons: 1) to have the mechanical pump as a backup, in case the electric pump fails. 2) to save the cost of a dummy mechanical fuel pump conversion.

Any help or advice is appreciated.

[Lane66Monza]

Start by reading ths first. Discussion In link will answer more questions that you will have when you start really thinking about how to go with the Iinstall.


Electric fuel Conversion Discussion started in August 2021 with numerous posters.
viewtopic.php?t=17257

[Dennis66]

Is it possible to install an electric fuel pump and keep the mechanical fuel pump in place, but remove the push-rod for the mechanical pump?

I'm thinking about doing this for two reasons: 1) to have the mechanical pump as a backup, in case the electric pump fails. 2) to save the cost of a dummy mechanical fuel pump conversion.

Any help or advice is appreciated.

WHY? The electric would only continue to pump fuel through any failures (leaks) in your mechanical - into crankcase or engine compartment. Dennis

[Frank DuVal]

Well, what is you reason for wanting an electric fuel pump?

1. Vapor lock correction
2. Avoid mechanical pump leaks
3. Avoid prolong cranking after a rest
4. Because Steve Goodman does it

If #2 is important, then keeping a mechanical pump in circuit defeats that. Use a bypass plate.

If #1 and #3 are important, then you can keep the mechanical pump and use it all the time, just mount a switch under the dash to turn on the pump when necessary. But do remember to turn it off. I do it this way, on my AC cars, works for me, but I do still get leaks when the diaphragm fails, so not perfect!

If #4, then that is a good reason. And you will need either a bypass plate (to look stock)or install the fuel lines on opposite sides, with the T in front of the fan, and plug the fuel pump hole.

Plus of course the safety wiring changes since the pump is running all the time. A search on here will bring up some schematics.

[RKF]

Thanks Frank. Actually reason #5 is important to me. Using an electric pump to push the fuel through a healthy, but idle, mechanical pump provides a level of redundancy. If the electric pump fails, then I re-install the pushrod for the mechanical pump and proceed down the road. But my questions is, is that even possible?

At least that was my initial thinking, although the first four reasons make sense too.

[66vairguy]

Thanks Frank. Actually reason #5 is important to me. Using an electric pump to push the fuel through a healthy, but idle, mechanical pump provides a level of redundancy. If the electric pump fails, then I re-install the pushrod for the mechanical pump and proceed down the road. But my questions is, is that even possible?

At least that was my initial thinking, although the first four reasons make sense too.

Many use electric fuel pumps to just "prime" the system then leave them off and let the mechanical fuel pump work. Most electric pumps do allow the mechanical fuel pump to draw fuel through them when they are off. That said electric fuel pump failures are uncommon.

May I suggest that if you want the option to run the mechanical fuel pump, then carry a spare and run the electric pump with a fuel pump that has the "dummy" through plate in it. It takes no more work to swap mechanical fuel pumps as to remove one to install the pushrod. Just my

My solution to this issue is simple --- I have AAA and Hagerty extended tow insurance. Sure make a trip in the Corvair less stressful -

[Wittsend]

Think about it, you are going to the electric fuel pump because of concerns (redundancy) about the mechanical pump,..., but you are wanting to rely on the mechanical pump if the electric pump fails. It brings me to the question as to what would be so difficult to change out the electric pump? Is it any more work than to install the mechanical push rod?

I put mine in ('61 Lakewood) with one bolt and slip connectors on the electric side. Clamp the line to the tank, remove two hose clamps, pull the electric connectors and remove the bolt (reverse on install). Depending on the season it might be appreciated laying down, shaded under the car rather than leaning over a hot engine with the sun beating on you.

I've used the cheap $15 clickity/clacks (and carry a spare pre-wired with connectors) with no real problem but buy a $60 Cube if it gives peace of mind. FWIW I have a clickity/clack that was OEM in a Mazda Rotary truck from the 70's. 50 years later I still use it to pump fluids (such as to move solvents through a Corvair oil cooler).

[bbodie52]

The electric fuel pumps I have placed in-service appear to be very reliable and relatively easy to change-out, if necessary. I believe that reliability of the electric fuel pump is greatly improved when a quality fuel filter is placed in-line, between the fuel tank and the pump inlet.

Mounting the pump close to the fuel tank, near the Corvair centerline is somewhat problematic and hazardous if you ever need to install a replacement on the road. Without jack stands it is dangerous to attempt to work under the car while trusting only a jack (hydraulic, scissors jack , etc). Some fuel pump models specify the need for a gravity feed to the pump inlet near the tank, but i found that the Airtex E8251 is a pump designed for marine service, and does not need to be close to the tank. I prefer a mount somewhere above the transaxle, in the firewall area, where it is relatively cool and protected from weather or hazards. I prefer connecting it through an electronic fuel pump controller that cuts off the pump if the engine stalls. A fuel filter in-line between the pump and the tank protects the mechanical components inside the pump from contaminated fuel, which helps to insure a long pump operational life. Gaining access to the pump does require jacking the vehicle and removing a wheel, so I always carry a pair of jackstands in the trunk to support emergency roadside maintenance.

I don't believe that fuel can pass from an electric pump through a disabled mechanical Corvair fuel pump, because the internal one-way valves in the Corvair mechanical pump would block fuel flow. It is probably best to abandon those aging 50+ year old mechanical pumps and get them out of the fuel flow path. An internal leak in the old diaphragm can permit fuel to drain into the engine crankcase via the pushrod location, which is not a good thing!

With an electric fuel pump and filter mounted outside of the engine compartment, you can get fancy with fuel line distribution by running the fuel from the pump into a firewall-mounted fuel distribution block. Safe fuel lines can then be run directly to the carburetors — avoiding the fan belt area clutter and hazards. A mechanical fuel pressure gauge could be added to a fuel block outlet, if desired, to monitor the electric fuel pump outlet pressure.

[RexJohnson]

The electric fuel pump would be going with the flow of the one way check valves so that would not be a problem. Even so I would not leave it in the line. If you are going to leave in the line just incase go ahead and use it and carry the electric as the back up. On my conv I run a mechanical pump but I carry an electric that could be hooked up to get me home.

[66vairguy]

Brad made a good point about using a fuel filter. Some of the electric fuel pumps come with a little fuel filter that will plug up fast if the car has an older fuel tank.

You can use an inline universal fuel filter with a 5/16" hose fitting. Just make sure it has a metal case, not plastic and never install it in the engine compartment.

FRAM G2, WIX 33012, Purolator F20011M. Note some companies sell both plastic and metal housing under the same number.

[RKF]

Thank you all for the enlightenment. Acting on the advice provided in this thread, I installed an electric pump below the passenger floorboard of my new (to me) Lakewood, yesterday, and used a bypass plate in place of the original fuel pump. I also placed a metal inline filter between the tank and the pump inlet. I got 12 volts from the heater blower circuit. My next step is to add a relay to shut the pump off when the oil pressure light comes on.

Thanks again for everyone's help.

[jimbrandberg]

If the fuel pump quits working when the oil pressure light comes on you can't fill the carburetors before starting the engine. I prefer an inertia switch under the dash in case of an accident along with a toggle switch in case I want to turn the pump off with the key on like when working on the ignition or lights.
Jim Brandberg

[RKF]

<<If the fuel pump quits working when the oil pressure light comes on you can't fill the carburetors before starting the engine.>>

On my other Corvairs, I installed a normally open momentary pushbutton "prime" switch across the relay contacts. Pressing the button allows the pump to run while the oil pressure light is on.

[Dennis66]

Pictures of your installation would be nice. Dennis

[Frank DuVal]

I don't believe that fuel can pass from an electric pump through a disabled mechanical Corvair fuel pump, because the internal one-way valves in the Corvair mechanical pump would block fuel flow.

Nope! The fuel flows through the mechanical just fine, as that is the normal direction of fuel flow in the system.

As I said, I mount an electric down by the tank, behind the body "crossmember" next to the tunnel, and I use it to prime the carburetors and during vapor lock episodes that are more common on AC cars. If the electric could not pump through the mechanical, then this operation would not work. Also, if the mechanical could not pull through the electric (and some pump designs will NOT ) then this arrangement would not function either.

On my non-Corvairs I mount them along the frame.

The difference in changing an electric and a mechanical on the side of the road is the mechanical can be done without fear of gasoline rushing out when the pump is removed (unless pointed uphill with a full tank Ha!). Brad's location would be similar to the mechanical, might be a dryer change.

I too like the WIX filter, but I buy the 33032, same filter, comes in a box with hoses and clamps. I've never seen the 33012, now I have to go compare price and availability when I run out of 33032 on the shelf.... because I do not always need the hoses and clamps.

I put that filter in the fuel line junction behind the left rear wheel even on mechanical pump Corvairs. Easy to change, fuel does not run out (unless pointed uphill....) like a filter at the tank outlet will.

That Revolution Electronics controller primes for three seconds on turn on, and of course while cranking there is a tach signal. Enough to turn on pump?

Glad to hear you got it mounted, Roger!

[66vairguy]

If the fuel pump quits working when the oil pressure light comes on you can't fill the carburetors before starting the engine. I prefer an inertia switch under the dash in case of an accident along with a toggle switch in case I want to turn the pump off with the key on like when working on the ignition or lights.
Jim Brandberg

Correct ---- one of the reasons for the electric fuel pump is to fill up the carburetors before starting the engine (today's gasoline dries up in a few days of sitting, even the non-alchohol fuel). If you want the fuel system to shut down if the engine stops I suggest using an ignition sensor system. The Revolution box has been around for years, so far no known complaints. It has a great feature the turns on the fuel pump when you turn on the ignition to prime the fuel system. If the engine does not start, or shuts off, then it shuts off the fuel pump. See https://revolutionelectronics.com/Produ ... _Pump.html

The only other safety feature you might consider is an collision impact sensor that shuts off the fuel pump if you hit something, or get hit.