Adding an auxillary electric Fuel pump

[Deleted User]

I am sure this has been discussed many times before, but I am still fairly new to this and am having trouble finding old discussions. So please bear with me. I think its time to put in a back up electric fuel pump to kick on when I start to vapor lock (its this new fuel!) anybody have a suggestion of a specific brand and model number of electric that will give me the right flow while still letting the mechanical one do its thing? This is all going on a 56' 308. Thanks

GrimGreaser

I have a carter rotary vane pump on my Jimmy. Works great. I believe they don't need a return either (mine runs through the old pump with a return).

http://m.summitracing.com/parts/crt-p4070 (they sell a 6v one too)

It free flows pretty good, but I just have it run all the time. If you're looking for only priming there are cheaper pumps out there.

Uncle Josh

My 52 Hornet had one inline under the middle of the car when I got it. Gasline was cut and it was spliced in with rubber hose. Operated by a switch under the dash. I only use it to prime the carbs and overcome vapor lock.

Make sure the screen in the mechanical pump is clean. A dirty one will increase the vacuum and increase tendency of fuel to boil.

I think Walt's solution of a tank return is the best setup as a lot of cool fuel is running thru the pump all the time.

ratlee2

I installed a Mr. Gasket electric pump right after the tank and hooked it to a toggle switch on dash to prime carbs before starting. Never had a problem with it fuel starvation with it in line. I onlt run it prior to starting though. Just make sure you get the one for carb engines, not high pressure fuel injection.

Rich

RonS

Andrius, are you vapor locking? or fuel starving? They are related. For about the last 10 years I have been annoyed by the fuel starvation that would occur when the Arizona temps ran over 90 F. I have tried every possible option, including the "feedback line", all three designs of electric pumps with & without a separate fuel line for the mechanical vs the electric. I have a 53 Hornet 308 w/twin H bored .060 over ( a bit warmer engine temp). Last year I solved it. First I sent my AC (mech) to Then & Now for a rebuild placed enough gaskets on the flange to produce 5 psi ( I believe 5 gaskets in the stack). Pulled both carbs( WA-1) and put in Craig valves for the floats. Then added 5 Ford insulator gaskets under each carb ( 3 below the shield, 2 above it). Placed an AC Delco solenoid electric pump(6v) just below the seam of the gas tank in line. That is for priming, since I have never had to use the electric after the car is started, any more. Walts idea is good( feedback). Read his instructions entirely. My problem was the eraticly weak diaphram in the AC mech pump that started with 4psi and as the engine heated up, fell to 2.75 psi. Too low for that big 6 under load. Now you have some more options with the 12 volt. If you have drivability problems, and wish to use the EP more often than not, the rotary vein type is a good choice, but you may need to run a bypass line around it, if it will be inline. IMO,The little solenoid ( Airtex E 8012) is too small to run the car on its own, but ok as a booster. Do a fuel pump test, at idle and also while driving( need to run a fuel line into the front seat with the gauge . observe readings). The EP that you buy MUST be a free flow style,ie, fuel can be drawn through when it is not switched on, otherwise you will always need the EP on... that can be a fire hazzard. Not as simple as it appears. PM me if you care to. Ron

DocHornet

It is hard for me to get too concerned about the "fire hazard" from an electric fuel pump, especially since virtually every late car on the road does have a continuous operation electric pump running at 60-70 PSI. A pump designed with carburetors in mind (i.e. 5-6 PSI max pressure) doesn't pose nearly the hazard, assuming you're not relying on 60-year old rubber fuel hose.

I've completely eliminated my mechanical pump (although still in place), replaced my fuel line from tank to carbs, and run a continuous-operation rotary vein pump without separate switch (except, of course, the ignition, which I can just as quickly turn off in case of some emergency). Every British car built in the 50's and 60's had the same setup... electric pump switched only by the ignition. I have this similar setup on 6 of my vehicles and each has worked flawlessly with never a vapor lock issue, even in 110 degree Texas heat.

I've had good luck with the AirTex pumps, never had one fail yet, but do keep a spare in the garage just in case (much easier to swap out than a mechanical one!)

37 CTS

To all this I wish to add , the electric fuel pump should be located as close to the tank as possible for it to perform properly. If you do have return lines they should be run under the car. I once saw some that were run into the passenger compartment. That is not safe.

[Deleted User]

I have a question DocHornet? if you eliminated your mechanical pump, how did you hook up your vacuum wipers, and the other line that goes from the pump to the carb, not the fuel line?

SuperDave

A note of caution with full time electric pumps .
make sure you remove or bypass the mechanical pump. A broken diaphram in the mechanical pump can lead to fuel contamination of your engine oil! Can your engine survive on a 50-50 mix?? Also in an accident where the ignition may not be turned off, fuel can be pumped through a leak caused by the accident. Usually into the engine compartment. The driver may not be thinking about a fuel leak! Most modern cars have a computer control on the electric pump that shuts it down after a few seconds of no oil pressure. Also many have switches that open upon impact and can be reset.

GrimGreaser

Most electric fuel pump instructions suggest (strongly) to have a oil pressure switch in-line with the fuel pump. Engine stops - no fuel.

Nevada Hudson

Mine now vapor locks All the time when it is over 90 degrees. It has the 352 Packard v8. It came with the small factory 2 barrel as Packard did not offer the big Rochester carburator to Nash and Hudson. Packard was afraid the Nash and Hudson would out perform their cars, as they were lighter with the unibody. Found a 56 Packard 400 in a junkyard and used it's manifold and Rochester 4 barrel on the 56 Hudson. It runs great with that setup, and is much faster! But, noticed that the original stock 2 barrel has a return line to the gas tank. The Rochester does not. Burned up several electric fuel pumps. Actually, when the car was starting to vapor lock, the electric pumps really did not help much at all.

RonS

Is your electric pump(EP) in line and where is it mounted? What type of pump. Solenoid pumps are the only ones that let fuel pass when not running, but IMO not able to send enough volumn to the carb alone. That means the mech pump (MP) is still an intricate part of the fuel delivery. What are the MP( alone) pressure and suction readings at idle and while driving? An occasional clog in the pickup tube, hot metal lines( especially before the MP), Gas boiling in the carb due to heat resonating up from the manifold ( better insulating gaskets). There are other things, but I would start there. Carry ice water and old socks saturate the socks & stuff em around the carb base to cool off the carb and eliminate one possible cause. Are you still 6v? Oh! I forgot one thing, Is the gas in the tank formulated for winter. If so lose it and keep summer fuel in as much as possible. This time of year winter gas and a good hot May day is trouble.