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Electric fuel pump conversion
https://slantsix.org/forum/viewtopic.php?t=34693		 Page 1 of 2
Author:  Jopapa [ Sat Apr 04, 2009 9:04 pm ]
Post subject:  Electric fuel pump conversion
I've been tossing around the idea in my head to install an electric fuel pump with a fuel pressure regulator with the Holley 1920 I'm running now. I'll need it for the Weber carb I plan on using when I swap the new(er) slant in but was considering just going ahead and doing it so it's one more thing done and ready for the swap. My biggest question though, is should I use a regulator that utilizes a return line, or not? If there are any benefits to using a return line, I've got nothing against doing the work to plumb one in. If there are no real benefits, then, well, bonus.

I'm really in no rush to do up the electric pump. I'm really only thinking about it for the sake of having one more thing out of the way for when I do the swap. Is there really anything to be gained over a well-working mechanical pump by converting to an electric pump with pressure regulator?
Author:  Bing Kunzig [ Sun Apr 05, 2009 10:30 am ]
Post subject:  electric fuel pump
I had an auxilary electric fuel pump on my '57 Studebaker. It comes in handy if you ever have vapor lock problems.I did have a return line. When the stock fuel pump started leaking, I removed it and just kept the electric one. A lot of people with collector cars have switched to electric. I'm not sure you would need a return line if you had only an electric pump. I also have a Weber carb on my '63 Valiant.
Author:  Mister_Perkins [ Sun Apr 05, 2009 2:25 pm ]
Post subject: 
I actually just installed an electric fuel pump on my 87 d150 today. The only reason I installed it was because I have been having a LOT of problems with my truck stalling, and my mechanical pump ended up having a worn lobe on the crank shaft causing it to only pump out low pressure.. like 1-2 Psi. Its nice too because if it is starving for fuel you can hear the pump clicking. I dont know.. I think they are nice to have. Easier to replace too compared to a mechanical pump. I mounted mine right on the Pass. side wheel well in the engine bay. Seems to be working fine for me.
Author:  vynn3 [ Sun Apr 05, 2009 5:17 pm ]
Post subject: 
Quote:
I actually just installed an electric fuel pump on my 87 d150 today. The only reason I installed it was because I have been having a LOT of problems with my truck stalling, and my mechanical pump ended up having a worn lobe on the crank shaft causing it to only pump out low pressure.. like 1-2 Psi. Its nice too because if it is starving for fuel you can hear the pump clicking. I dont know.. I think they are nice to have. Easier to replace too compared to a mechanical pump. I mounted mine right on the Pass. side wheel well in the engine bay. Seems to be working fine for me.
I thought electric fuel pumps were supposed to be "pushers", mounted close to the gas tank?
Author:  Reed [ Sun Apr 05, 2009 5:35 pm ]
Post subject: 
Quote:
I actually just installed an electric fuel pump on my 87 d150 today. The only reason I installed it was because I have been having a LOT of problems with my truck stalling, and my mechanical pump ended up having a worn lobe on the crank shaft causing it to only pump out low pressure.. like 1-2 Psi. Its nice too because if it is starving for fuel you can hear the pump clicking. I dont know.. I think they are nice to have. Easier to replace too compared to a mechanical pump. I mounted mine right on the Pass. side wheel well in the engine bay. Seems to be working fine for me.
Well, the fuel pump is driven off the camshaft, not the crank, and it doesn't put out that much pressure. The 1984 Factory Service Manual calls for 3-4.5 pounds of pressure from the fuel pump.
Author:  Mister_Perkins [ Sun Apr 05, 2009 6:38 pm ]
Post subject: 
I thought it was the crank shaft because it was towards the bottom. Regardless I was just saying that it wasnt putting out the right amount of output so i replaced it. 1-2psi isnt too high? too low maybe
Author:  Jopapa [ Sun Apr 05, 2009 7:15 pm ]
Post subject: 
Yeah I also thought they were better off being mounted as pushers close to the tank. That's how I was planning on going about doing it.

So a return line probably isn't necessary for the BBS or the Weber setup, huh? It sounds like having an electric over a mechanical might be better from a reliability standpoint. I could also easily carry a spare in the toolbox I plan to mount in the trunk (along with all my spare ignition parts).
Author:  kipamore [ Fri Apr 10, 2009 6:18 am ]
Post subject: 
Electric pumps are nice for a few offhand reasons I can think of:

1. Easy to test/diagnose. You can hear the pump, you can pull the return line and confirm that it's flowing fuel. You can pressure test at the return line with the engine off.

2. Easy to prime. This is really the point of the return line - to give air a place to go and allow you to prime the system

3. Convenient place to get gas for the mower! Wire in a secondary switch that allows you fire the pump with the engine off. And an easy to use nipple for a hose. No more gas cans, no more gas can spills in the trunk. No more hunting around for "parts washing fluid"

4. Poor man's anti-theft device.

Downsides:
One more thing to go wrong
Possible leak points
Author:  SlantSixDan [ Fri Apr 10, 2009 6:31 am ]
Post subject: 
Quote:
I thought electric fuel pumps were supposed to be "pushers", mounted close to the gas tank?
That's correct, they are.
Author:  SlantSixDan [ Fri Apr 10, 2009 6:36 am ]
Post subject: 
Quote:
Downsides:
One more thing to go wrong
Possible leak points
And an enormous safety hazard if engine stalls or car is in crash with ignition left on or carb inlet needle/seat sticks open. The electric fuel pump will happily pump the whole contents of the fuel tank up to the engine bay and out thru the carburetor. It is possible (and very wise) to install an inertial cutoff switch and to include the oil pressure sender output into the wiring for the fuel pump relay, with a bypass circuit live when the starter is engaged. That handles the worst of the safety hazard.

I still don't prefer electric pumps in carbureted applications, tho; I view them as a get-by measure until camshaft with worn pump drive eccentric can be replaced.
Author:  Mister_Perkins [ Sat Apr 11, 2009 2:18 pm ]
Post subject: 
It says on installation of electric pump to install an oil pressure switch or hook up to an oil pressure switch so if your engine stops your pump will stop. Because like dan says it will just keep pumping otherwise.
Author:  six popper [ Sun Apr 12, 2009 5:27 am ]
Post subject: 
Most high pressure pumps require a return line. I don't feel it would neccisarry to run a pump with that much pressure on a /6 that is carbed or naturally aspirated. There is a couple of gains to running a return line though, ie pump never has resistance therefore in my thinking should make it last longer. If you have a filter before the pump then the fuel that circulates will get filtered more.
Author:  Mister_Perkins [ Sun Apr 12, 2009 7:23 am ]
Post subject: 
I removed my mechanical pump and installed an electric pump on mine using the stock fuel filter (well recently replaced). It has a return line right on it. I mounted my pump right next to my coil. Works great. no problem. its a 4-7 Psi pump.

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Quote:
Most high pressure pumps require a return line. I don't feel it would neccisarry to run a pump with that much pressure on a /6 that is carbed or naturally aspirated. There is a couple of gains to running a return line though, ie pump never has resistance therefore in my thinking should make it last longer. If you have a filter before the pump then the fuel that circulates will get filtered more.
when you install an electric pump, you only want it to be right around the same pressure as the mechanical pump. If you try to put a high pressure pump on your vehicle thats carburated, it will give it way too much fuel and probably blow most of your lines. Your talking 50-60psi right? fuel injection lines? All fuel systems need a return line. if you have no return line your pump would pump way too much gas. Unless your vehicle ran at one set RPM and had one set Speed and that would match the flow rate of the pump, which doesnt happen.... it wont work. You need a return line.
Author:  six popper [ Sun Apr 12, 2009 7:53 am ]
Post subject: 
Your exactly right, the pumps I were talking about are more of a performance pump that can run anywhere from 5-20 psi for carberated engines. Holley makes pumps that run 4-7 pounds that require a regulator but no return, again more of a performance pump.
Author:  Mister_Perkins [ Sun Apr 12, 2009 8:04 am ]
Post subject: 
Quote:
Your exactly right, the pumps I were talking about are more of a performance pump that can run anywhere from 5-20 psi for carberated engines. Holley makes pumps that run 4-7 pounds that require a regulator but no return, again more of a performance pump.
Regulators are used usually for 2 bbl or 4bbl applications or fuel injection applications. I think that the regulators are typically for higher HP applications and most regulators still do have a return line. There is low Psi regulators, but they still do have a return line. the Holley 12-803 for example is recommended for low-pressure applications that require steady flow. Factory adjusted to 2.7 psi with a 1-4 psi range. Accepts 3/8" NPT fittings. Adjusts from 4.5 to 9 psi. Also good as a high-pressure bypass. 2 regulators are recommended for dual 4-barrel applications.
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