When I bought my 54 pickup with stock 235 the PO had added an electric fuel pump and bipassed the original pump, he left the old fuel pump in the motor but is not plugged on either side of the pump. Does that matter in the way the truck would run? I want to go back with the old fuel pump should I just order a kit and rebuild that one? Is there any advantage or disadvantage to the electric pump or mechanical pump? I just don't like the way the electric pump has that added on look with rubber hoses and clamps? Thanks
Fuel Pumps Unless the old pump has a leaking diaphram , the newer , electric fuel pump should be plumbed so the fuel passes through the old mechanical pump . The benifit of a mechanical pump is : longer life and less troubles . The benifit of an electric fuel pump is : if your truck sits for a few weeks and the carby goes dry (it will) , the E - pump will fill it up before you begin cranking , this saves the battery and extends the life of the satarter too . The downside is : when you have a traffic collision , the E - pump keeps on pumping raw fuel at a prodigious rate even after the engine has stopped running , this can be (and often is) DEADLY . Lastly , most E - fuel pumps are incorrectly mounted ~ in all cases , they're supposed to be mounted as close to the fuel tank as possible . In any old pickup truck it is a simple thing to mount it on the frame rail , low and out of sight where it'll be quieter and work better . I'd rebuild the old pump and use it , you can leave the E- pump in and wire a momentary pushbutton for priming ~ I did this on my '59 Metropolitan FHC and it works a treat . it's also the bee's knees for curing vapor lock .
a little tip Some of you may know this but for those of you that don't...... A big block Chevy pump will work on a 235/261 if you mount it upside down....Big Tim
If I decide to go this route will the fuel run through the electric pump without it being on when it is not needed? So the object would be instead of having to pump the mechanical pump after sitting awhile I could just hit the switch and give the carb a jump start fromn the electric pump correct? Should I put a filter between the tank and the E pump? Thanks for the help!!!!
It is a good idea to filter the fuel before any pump but have it so it's easily serviced or replaced. Yes, the fuel will be drawn through the electric pump by the mechanical pump. I also have electric pumps on all my equipment to save from grinding on the starter till fuel fills the carb. Unlike Nate, I'm so absent (weak?) minded that I can't trust myself to turn off a toggle switch so I use a switch that is turned off by oil pressure. When the engine starts it turns the electric pump off.
I didn't know! Ain't to proud to admit it, Kain't remember S--T anyways. Keep on educating us Big Tim and all you other helpful readers, that's what we tune in for. BTW, is the Big block chevy pump a mechanical or electric? Flashlight
I am all done with mechanical fuel pumps.I am converting my fleet over to electric pumps. Recently had a mechanical pump dump raw fuel into crankcase of my '49. Oil pressure dropped to zero & it started clacking.... I pulled over to check the oil & the dip stock smelled like fuel. Good thing I shut it down quick or I would have been lookin' at rebuilding the entire engine. Upgraded to the Bosch/Facet electric fuel pump.... mounted under the inside frame rail next to the fuel tank. I retained the original mechanical fuel pump on the block for the appearance of originality but, I removed the operating lever that rides on the cam , used a flate block off plate between the pump & block & I put a block off plate in the top of the glass bowl {where the original rubber diaphram was } I still use the top of the original mechanical glass bowl pump as an inline filter but the pump itself is not operational. { the original fuel lines & pump look stock when the hood is opened} New electric Pump is run by a toggle switch under the dash { which doubles as a theft deterrent}. I also added a small pilot light on the dash to remind me to shut the pump off. The Facet pump operates at 4.5 to 5.5 GPM just like the old mechanical pump ,and it starts right up without alot of cranking even after the truck has sat for awhile & vapor lock problems are eliminated. It runs quiet & have had no problems with it at all. The Facet pump also has a built in removable & cleanable screen/filter. This top quality Bosch/Facet pump will run you in the area of $175 each from NAPA but, I found a wholesale source at around $100 with free shipping here.... http://www.carparts.com/autoparts/I...Id-100000280014/Pr-p_CATENTRY_ID:100000280014
I'm talking about a BB Chevy mechanical pump. By using one of these you have more options as far as increased fuel pressure if you need it....Big Tim
Theft deterrent... While some of you may scoff at the idea that a GMC needs yet another theft deterrent, I'm thinking this is a REALLY good way to go. I plan on using my truck as a daily driver, but my daily driving may be weekends only when I'm teaching. Gas tends to go somewhere after a few days of rest. This just sounds like a good idea. Thanks, DZ.
! Safety ! I like the idea of adding a pressure switch to the E-Pump's power feed , making it automatic to fill the bowl then cut off . I , personally follow the Engineering dictate of fuel filters after the pump(s) , usually up by the carby . I just removed the undercab one on my '76 Jimmy God along knows how many years it'd been there and was full of crud as no one ever wants to get dirty & crawl underneath just to check it out..... At least it had done it's job as the Carby's factory inlet porous bronze filter was clean as a whistle ~ that's a rare event these days .
