I'm going from an electronic fuel pump (v6) to the fuel pump on the motor (v8 carb'd). I haven't yet done this, that's why I'm here - I don't know what to do?! Can someone help please?



How does the mechanical pump work? Will it suck the gas to put it into the carb? Please explain the best you can. Thank you guys.

 

Well I'll try but its pretty late....uh. Mechanical fuel pumps are diaphragm pumps, mounted on the engine and operated by an eccentric cam usually on the camshaft. A rocker arm attached to the eccentric (by pushrod) moves up and down flexing the diaphragm and pumping the fuel to the engine.

Now that being said.....

You can either use the intank pump and a fuel pressure regulator or you can remove the pump and run a line to the mechanical pump side and use it. Either way. My friend is using the electric pump for his 383. I can find out how he hard wired it to work (can't remember off top of my head).

 

so if i decide to use the one on the side of the motor, then it will bring the gas from the tank, right?

 

yes of course. Thats what they are made for....sucking and blowing.

 

cool dude, thanks! it's either powered by the cam or the crank???

 

Its powered by the cam. The camshaft has a lobe on it just for the fuel pump. The lobe hits the pushrod which hits the rocker for the pump. That then moves the diaphram to pump the fuel to the carb.

 

So if I have an electric fuel pump now, how can I utilize the one on the block? What has to change?

 

one of two things.
Either...remove the intank pump and use the mechanical one.
Or.....put a plate in place of the mechanical one and use the electric pump.

You might be able to use both. One as a helper pump and one as the main. The intank pump will have too much psi so you will have to use a fuel pressure regulator. Personally I would just use the mechanical. Less problems to go wrong. Its not too complicated but you have to decide which way you want to do before I tell you how!!

 

I want to utilize the mechanical pump, any suggestions?

 

ok, well then I would just remove the intank pump. Drop the gas tank (removal of the panhard rod and exhuast is required for this) and you can unbolt a portion of the top. You will need to run a new line down into the tank with a strainer. I think the fuel line under the hood is on the drivers side so that will need to be either moved to the passenger side or a rubber hose running to the mechanical pump.

 

So does the line go all the way to the bottom of the tank? What's a strainer, can I buy one from Summit or Jegs or anywhere?

 

If you're going to remove the in tank pump, you'll have to create a new in tank pick up. It should extend down to the bottom of the tank. About a 1/2 " from the bottom. You'll have to re attach the gas guage sender float to the pickup tube too.
A strainer is optional but do use a good inline high flow fuel filter.

Do not use rubber hose to run to the engine mounted fuel pump
bend up a new piece of steel fuel line. Route the line away from any heat source. Any rubber hose on the suck side of the mechanical fuel pump can/will collapse if too long in length or gets too hot from under hood heat. Keep the rubber hose to a
absolute minimum. It's a bad fire hazard.

 

mechanical will pull thru the in tank eletric pump with no problems. i knew we all think SBC but there's a lot of other engines that use an ecentric bolted to the front of the cam (ford) to drive the FP

 

So Ede, are you saying that I won't have to remove the in-tank fuel pump? Will that eliminate me having to put a pick up in it?

I planned on running steel, or metal lines. How can I get the lines to the mechanical pump without a fire hazard?

 

You dont have to drop the tank unless you like to work on your car. The mechanical pump will pump fuel through the electric pump without the electric pump working.. lIke f-bird said use a good in-line filter not a Fram. Wix comes to mind as well as Purolator or even Ac Delco

 

I wasn't sure if the mech pump would pull through the electric one. Anyway, You could try using aluminum fuel line (dissipates heat better than steal). I doubt you would have any electrolysis problems between the steel line and the aluminum. You can flare the ends yourself and buy the couplings. An aluminum pipe bender is fairly inexpensive at your local parts store.