Technical noisy electric fuel pump

Hello, I just mounted an electric fuel pump to frame rail 1935 dodge it made quit a bit of noise so I changed the way it is mounted a number of times it is currently mounted on a thick piece of rubber with no bolts or medal touching pump or frame, but it is still noisy so I hung pump frame rail with 2 tie wraps and it was very quite I then remounted it and got under car to get better idea what is going on it is mounted half way between gas tank and engine with 3/8 rubber gas line I found out the gas lines are what is cause the noise due to vibration is this what they call cavitation and how do I correct it Thanks,Mike it is a carter p4070

 

I've always mounted electric fuel pumps close as possible to the gas tank,and always mounted on rubber. HRP

 

^x2

 

Just isolate the pump with a rubber mount to the frame and rubber hoses on inlet and outlet. Use enough hose to go from steel fuel line to fittings in pump and still let the pump move around a little. Let the rubber absorb the noise. Cavitation is the pump ****ing air from lack of fuel flow, not the vibration noise you are hearing. Move the pump as far back to the tank as you can, and lower than the fuel level so fuel naturally flows to the pump. Bottom outlet tanks work better then up and over the top feed lines. Electric pumps are great at pushing fuel, not so much at ****ing it. Most guys run the fuel pumps off a heavy relay so the pump gets maximum voltage. Smaller wires can be used for relay activation and the safety switch. You did use some sort of oil pressure safety switch didn't you? Chevy Vega's used a simple switch which can be had at most any parts store. With this switch, the pump only runs after the oil pressure comes up past 4 or 5 psi, depending on the switch. Incase of rollover or accident, the pump will shut down when the engine dies. On the same safety switch is a third prong which can be used for a primer ****on to fill the carb before starting after a long shut down.

Some pumps are just noisy, and no amount of isolation will help.

Joe

 

Electric pumps are noisy. You can isolate them and that helps but they are still going to be an electric pump. They do need to be mounted as close to the tank as possible and unless you are running braded lines you really need to hard pipe it.

cavitation is when the pump is trying to pump more air then fuel. That will trash your pump. be sure that the pump always has a good supply of fuel. In a perfect world the pump would be mounted close to the tank and below the fuel level.

 

What kid of pump are you using? I have a Holley Red on a couple of cars, and the only time I hear them is when I first turn on the ignition. Once the engine starts I can't hear it at all. They're mounted on a heavy rubber flap hanging from the frame on both cars. Neither of the cars are noisy exhaust, rumpity-rump engines. Stock 1956 New Yorker and an O/T El Camino.

 

Holley makes a quiet fuel pump. I think it's the black one

 

They are all noisy , run open headers and you will never hear the pump. LOL.

 

The reason they are call pumps is because you need to mount them close to the gas tank,the location where it is mounted might be the reason it is so noisy,it's being overworked. HRP

 

Electric pumps are noisy for a reason...they tell you when they are on and the motor is off! "Kinda" like a smoke detector.

 

a local street racer back in the '70s had a deuce coupe with a supercharged 426 hemi. he ran two electric fuel pumps that sounded like chainsaws!

 

My '40 coupe, which I bought as a driver and have changed nothing, has a Holley red pump, and it's not loud at all, in fact, if there's any background noise at all, you can't hear it even with the engine not running, but the ignition on. My roadster has a Carter pump, mounted on rubber biscuits with braided hose both sides. Makes a lot of noise when on with a dead engine, but with the barely baffled 3.5" side pipes, you don't hear it when engine is running, so who cares!
Of more concern to me is the tank design on the roadster, as it's a universal tank from Tanks, INC. DOT rules now require that all univ. tanks have their full outlet on top with an internal pipe in the tank to **** up fuel from near the bottom.
This means that fuel has to be ****ed up and out of the tank by the pump regardless of pump location. My pump is underneath the car almost directly underneath the trunk mounted tank, so once fuel flow starts to pump there is a sort of siphon action to pull fuel up out of tank and then flow down to the pump. So far no problem, but it is a concern.

 

Must have been Carters. That's what I use. Noisy but dependable

 

My fuel cell is the same way. Pump mounted under car below tank. Been that way for 10 years. No problems at all.

 

I actually ran a Mallory 110 directly above the tank on a car back in the '90s. About 7" of line to the filter that was coupled directly to the pump. That is absolutely against the rules, drove it for about 30K trouble free miles then sold the pump to a fella in Texas because he needed it and I needed the cash.

I have noticed if you plumb the pump with a return line it seems to be a little bit quieter. but with many pumps they claim it not to be necessary, for example the Holley red and blue pumps don't need a return line but the black does.

 

i mounted mine with little rubber isolating mounts, i can hear it when the engines off.

 

have a Carter on mine with the rubber insulators it is still loud

The old one was a Bendix I think and it had a cool clicking noise when running