Stock vs Electric Fuel Pump

[JSeery]

Based on another current thread there seems to be interest in the topic of stock vs electric fuel pumps. On a stock engine in an original vehicle, an original fuel pump would seem to be the way to go just about 100% of the time. I can see situations were it is a daily driver that installing an electric pump as a back up for priming or vapor lock seems an option to consider. Now, on highly modified applications an electric pump might have advantages. So what are your thoughts?

[Charlie ny]

I prefer mech pumps....I rebuild them and send them all over. I think probably everyone knows by now I do not trust commercially available kits or diaphragms. I have no
issues with the mech pump I built and installed 6 years ago in my '41. It feeds 264
cu in's thru an Olds Rochester 4 barrel and runs 70 mph in straight drive forever or way past that in Columbia OD with no starvation.
Charlie ny

[supereal]

I agree. The electric pump reduces the starting time after a long pause, and is helpful if the infamous "vapor lock" occurs, or the mechanical pump fails. If feeding multiple carbs, it should avoid "leaning out" as fuel demand increases. A good quality stock pump should suffice in most cases, if it is "fuel proof" to protect the diaphragm and valves from alcohol attack. Unless the stock system in an older vehicle has been replaced from tank to carb, and the electric pump is properly near the tank after a good inline filter is installed, it is a good "belt and suspenders" approach to trouble free to enjoying your vehicle

[Tim Ayers]

Charlie just built me a high volume pump using a glass bowl top from a 50's era GM OHV motor.

Charlie adapted it to a flat head base and it puts out 2.75 lbs of pressure with approximately 30% more flow than a stock pump. Should be plenty for my motor.

If it can be done, Charlie is the man.

[Bazooka Joe]

I run the stock mechanical fuel pump, on my 39 Ford. It has a Hi Performance 46 Flathead V8 with twin Ford carbs. Offenhauser heads and intake, headers, 3/4 race cam. Pointless 12 volt ignition. At least for me, the stock fuel pump seems to work OK. Been like this for many years.

[philipswanson]

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I run both, best of both worlds. Especially when they sit for a long time.

[Floyd]

Electric fuel pumps go into the same category as 12 volt , alternators etc. Why ??
Because you want to change something that works. Zillions of cars ran with these items for years trouble free. Fix properly what you got.
If you have to change something for change sake , add seat belts, turn signals , radial tires and brighter bulbs.
My opinion
32 and 40 ,bone stock- driving and running perfectly

[Mart]

I run both on my coupe and roadster. The electric is on a pushbutton just for priming after sitting. I started the coupe yesterday after sitting for 5 months or so. it went "first turn" or so it felt. I have it on video but need to edit it up.
My roadster did 100mph on the beach at Pendine with a stock pump and 1/4" pipes. that's 276 cu in and twin Holley 2100s. i also ran well at the drags woith no fuel starvation.
I much prefer the mech pumps but because mine tend to sit for a while, the SU pump as a primer makes a lot of sense.
Although I've never had to resort to it, the electric pump would get me home if the mech pump stopped delivering. As long as the failure wasn't due to a leak into the engine. If that was the case the same would still apply but the mech pump would have to be bypassed.

Mart.

[Seth Swoboda]

Originally Posted by Floyd

Electric fuel pumps go into the same category as 12 volt , alternators etc. Why ??
Because you want to change something that works. Zillions of cars ran with these items for years trouble free. Fix properly what you got.
If you have to change something for change sake , add seat belts, turn signals , radial tires and brighter bulbs.
My opinion
32 and 40 ,bone stock- driving and running perfectly

An electric pump mounted in the rear by the fuel tank on cars that are frequently driven help in a vapor lock event. In Southern Illinois where temps are 85 to 95 degrees May through September and the humidity is 90% daily, an electric pump operated by a hidden under dash switch has saved my driver cars often. Otherwise I'm an all stock, no modifications guy too.

[flatford8]

My ‘50 is stock and I drive it a lot (in the spring-summer-fall) with no issues. Temps don’t get real hot here and there ain’t a lot of traffic where I live. The 276 going in my ‘51, the fuel pump hole got sealed because of a mis-communication between me and the builder. So that’s going to be electric..... Mark

[Tinker]

Never had vapor lock in florida. I've had hot coils and condensers. I only run a single carb and stock stuff. If you have a good carb the bowl has plenty of fuel to start. If you have a old fuel line you might have a small leak from the tank to pump, making it hard to overcome.


Just my experience.

[Scotty's 52 F3]

I like the mechanical pump. I have a French Flathead pump with a priming lever which is nice for after sitting a long time.

I like the look of the stock pump so I had Charlie rebuild mine. So I guess I have a spare.

I drive in 100 degree temps and they seem to work fine.

I did block the heat risers and have a phenolic spacer under the carb.

[Tinker]

Great point. Ya I blocked the rises also in Florida, couple thin tin shims with ears to remove. No need to heat the carb in hot climate. Still have them in Mn and it takes a few miles to warm up. Little choke for a bit, then good no exhaust heat on the carb/intake. Heat risers are not as crucial.


Sometimes we forget they made these cars to run in all climates. Most of us never run our cars when it's 10 below. But they did, and at 100 degrees too. Made for both.

[dwick01]

I use an electric pump only for prime as my car sometimes sits for long periods of time. Also use it to safeguard against vapor lock. I have it setup on a spring-loaded toggle switch. I have no problems with the stock fuel pump at all. It is hooked up to a Charlie NY overhauled carburetor which also works perfectly.

[JWL]

For those of us who have more projects than we can properly handle the electric and mechanical combination is great.

[Seth Swoboda]

Vapor lock, for me, is a problem on hot days when I park and shut off the car. The temps in the engine bay rise and the fuel in the line near the carburetor vapor locks. I even run no ethanol gas, which helps some. I don't mean to hijack the thread but wanted to say that the electric pump will overcome this situation for those who do a lot of touring.

[Tinker]

Seth that is a fair point. It seems that the underhood temp goes up at least 20-30 degrees when you turn the car off. I do sometimes after a longer drive and stop (surely not the distances you do), i will put the hood sides up. A backup pump for starting would be beneficial.

[JSeery]

Originally Posted by JWL

For those of us who have more projects than we can properly handle the electric and mechanical combination is great.

Good answer! IMO

[philipswanson]

Originally Posted by Floyd

Zillions of cars ran with these items for years trouble free.

No back in the day we had allot of problems with vapor lock on the old Fords due to the pump's location being trapped in the back of the hot running flathead.

[tubman]

Originally Posted by philipswanson

No back in the day we had allot of problems with vapor lock on the old Fords due to the pump's location being trapped in the back of the hot running flathead.

Just curious. When was "back in the day" for you? If they weren't in the fifties, these were just old badly maintained cars with the attendant problems.

The fact that you said "old Fords" gave me a clue.