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6 volt electric fuel pump

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#1 pint4


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Posted 22 May 2009 - 11:29 PM

I would like to add a 6 volt electric fuel pump to my 1935 Buick Series 40. Can anyone tell me what they have done. Have you used a 2 to 4 psi pump or a 4 to 6 psi pump? If I by pass my current mechanical pump, what would you recommend? If I put it in line with my current mechanical pump and run the fuel through it, what would you recommend?

#2 Mark Shaw

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Posted 23 May 2009 - 02:11 PM

My 38 Buick has an in-line electric fuel pump that works well just to fill the carb bowl prior to starting (it significantly reduces cranking time). It is located near the fuel tank and works well as it is not running after starting. I am not a fan of electric fuel pumps, but this one came on the car when I bought it. If it fails, it won't effect the operation of the original pump, so it can't leave me stranded if it fails.
Mark Shaw BCA #40988
BCA PreWar Div. Director
HCCA Member (Skagit & Portland)
1912 Buick Model 34 roadster
1913 Buick Model 31 Touring
1915 Buick Model C-25 "Speedster"
1924 Buick Model 45 "Roadster Truck"
1929 Buick Model 29-27 Sedan (Now my son's car)
1931 Buick Model 57 Sedan
1938 Buick Model 48 Sedan

#3 Marty Roth

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Posted 23 May 2009 - 05:08 PM

On many of our cars, we use the electric pump to prime the system prior to starting -- that way the car generally starts on the first turn -- then I shut off the electric pump. When you switch the pump to run, you will likely hear clicking - fast at first, but then slowing as the fuel system builds pressure. After the clicking slows or stops, cut off the pump and your car SHOULD start without excessive cranking or battery drain.

On our cars which may be subject to vapor-lock ('41 Caddy with the carb right ahead of the exhaust manifold crossover pipe) the electric pump can be switched-on to push the fuel through to keep us running - even in slow/hot-running conditions.

I think that electric pumps should be ADDED, but not replace your original.

Also, remember that your mechanical pump is a puller (or sucker), but electric pumps are a "Pusher". Therefore the electric pump should be mounted as low and as close to the tank as possible, preferably grounded directly to the frame (depending upon your car's polarity - of course).

The electric pump should have a cut-off switch in easy reach of the driver, and be fused independent of the ignition circuit. When your engine cuts out the mechanical pump also quits, BUT AN ELECTRIC PUMP COULD KEEP PUSHING FUEL, EVEN IN AN EMERGENCY SITUATION, potentially feeding a fire.

The eletric pump can get you back home even if the mechanical pump fails - also if the mechanical pump diaphram were to fail and push gas into the oil, a simple bypass of the mechanical pump can still save your engine -- I've been there!

I've seen some hair-brained wiring set-ups (even done some in my early days) that would invite disaster under the right(wrong?) conditions - you know - just to try it out for now, and several years later a bum connection results in a garage fire or worse.

Go ahead and have a backup system if the car is a driver, but do it safely and enjoy your rolling piece of AMERICANA.



1986 CHEVY SUBURBAN 2500 454ci
1988 BMW 528e

1954 U-HAUL

#4 Patrick W. Brooks

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Posted 24 May 2009 - 03:45 PM

Marty has given you sound advice. I have installed electric fuel pumps on Buicks from 1925 through the straight eights. The best and easiest to install is made by Airtex which is in Fairfield, IL 62837. The 6 volt is #E8011 and the 12 volt is #E80165. These can be ordered from your local parts store. I have recommended them for many years and each time have had excellent feed back from those who installed them. The instructions which come with them are excellent (I took the time to review them again this morning to be sure.). It is best to connect it through the ignition so it shuts off each time the car is shut down (in case you forget to do so). I also wire the pump through a flip switch so I can manually shut it down while the car is running and rely on the mechanical pump. As others have stated, it is usually relied on for priming the carb for immediate starting. This saves wear on the engine and starter and makes it less likely the novice will flood the engine. My recollection is that the pumps mentioned above are in the four pound pressure range. (I check the specs on the cars years ago and found these complied.) They can most easily be installed on the frame just in front of the rear tire and under the rear door. I have always found a round hole or two in the frame which can be used and relieve the need to drill any holes. The pump comes with a filter which is metal so the contents cannot be seen. I substitute a clear plastic filter so I can see what is happening. Most times I bolt a six or seven inch piece of flexible sheet metal through one of the frame holes and have predrilled the sheet metal with another hole to which I bolt the pump. This makes room to do the installation easier. Remember to follow the fusing instructions. You can either wire in line a single fuse holder or, if you have other accessories you want to install, bolt under the dash a fuse terminal. The terminal has one hot wire from the ignition running to a post and then there will be a number of terminals to which power runs and each has a separate blade fuse (blade fuses are much easier to work with). Otherwise, you must run multiple wires to the ignition switch or other power source. I like the electric fuel pump on my straight eights as changing a mechanical fuel pump on them is tough along the road as they are hard to get to. I have two ways of dealing with this. First, the out line to the carb is at the bottom of the mechanical pump and tough to get to under ideal conditions. This line runs up the front of the engine and to the carb. I cut this line above the mechancial pump and install a short piece of rubber gas hose and then only have to disconnect there instead of under the mechanical pump where you cannot see as you work. When lifting the mechanical pump out this short piece of metal gas line at the bottom simply lifts out with the pump. Second, I carry a piece of rubber hose long enough to reach to the carb connection after disconnecting the gas line from the mechanical fuel pump. This bypasses the fuel pump which could pump fuel into the crank case and cause engine failure. Hope this helps. Contact me if you have questions. Patrick W. Brooks, email: Brooker50158@hotmail.com

#5 pint4


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Posted 24 May 2009 - 06:05 PM

Thanks for all the input from everyone. I definitely want to install one on my car so the helpful hints are really appreciated.

#6 pint4


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Posted 24 May 2009 - 09:08 PM

Thanks for all the input from everyone. I definitely want to install one on my car so the helpful hints are really appreciated.

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