I am "hopping up" a model A engine. I added a home made lake style header with a holley carb. I have seen many photos on the HAMB of four banger motors. I noticed almost all of them did not have a fuel pump. Does it operate better without a fuel pump? Is one really needed? Would it perform better with one? I have a low pressure pump. Did not want to put it in unless I needed too. Could use some help from someone who has worked on one. I need some feed back. Thanks for your time. Marty
a model A engine does not have a mechanical fuel pump , it was gravity feed from the cowl mounted fuel tank....so i assume you are talking about an electric? FYI , ford added a boss for a mechanical fuel pump on 4 cylinders in 1932
Most likely you will need a fuel pump for the following reasons. 1 The stock A had a up draft carb that was mounted quite aways below the fuel tank and WAS designed to be gravity fed. 2 The carb you now are using is mounted much higher and was designed to be fed under pressure. Basic problem is you will not have enough gravity head [pressure] to give the carb enough fuel. I know some people have got away with no pump so try it that way first. It works OK great ,if not add the pump. Might be fine with a full tank of fuel and as level drops starts running poorly.
I ran mine with no pump for a good 1000 miles but I would run out of gas up big hills I would have to get gas every ride pain in the ass. I put a pump in 2 weeks ago.
I've heard of putting the pump down low, running a line on to it inside the the firewall and back up and out the original exit so it looks stock on the engine side. Holley 94s only need a few pounds of pressure if what I've read is accurate - put a regulator on it.
I had a elec pump failure with my AV8, so I by-passed the pump and went gravity feed to get home. The next day I put the lawn mower gas can in the rumble and went for a long ride. Ran that puppy right down to the last drop. Added the lawn mower gas and drove to a gas station. I ran it like that for the rest of the season. It would run out of gas on a long climb, but if I got out of the throttle, it would recover. I replaced the elec pump that winter, but to this day, I carry that piece of by-pass hose just in case. OH yeah, I run 2X2's on a Thickstun hi-rise.
I'm guessing that you simply couldn't see the fuel pumps, rather than them not having one. I run two bangers and have tried both with gravity feed, one with a Weber 32/36 progressive and one with a 94 (later changed to a 97). Neither ran very well, to be honest, and on hills you can forget it. I have my fuel pumps inside the chassis rail, underneath the passenger's feet. It's fairly close to the silencer but I've made a little ali heat shield that goes around the pump, though I'm not sure it needs it. Just run a fuel line from the original point on the bulkhead, down to the pump - always use a filter - and then back up to the carb.
Hello, Thanks for all the replies. Very helpful. I just wanted to do it right the first time. I have a low pressure electric fuel pump ready to go. I will put it in tomorrow. If you have anymore suggestions, I would like to hear them! Thanks for your time everyone! Marty
We put a low volume 6 volt Carter (positive ground) electric pump on the 31. Mounted it under the cab plus a fuel regulator and then ran the line up and out through the original glass gravity filter system, then to a fuel block and then to the two 97s. Works perfect. Makes everyone that sees it THINK you can run dual 97s on gravity (but you can not)!
in the old days, grandpa would back his model a up a hill if he was low on gas. also, a lot of hot rodders would pressurize the fuel tank with a manual pump.
Thanks- I'll check it out tommoro. I'm glad there's so many Banger enthusiasts on here; there's a ton of good info.
I am assuming the fuel pump is mounted to the right frame rail under the front floor, correct? I had thought of doing this but wondered if I would have any problems due to the heat from the muffler. Is this your setup and wondering if you have had any heat related issues? thanks