Technical mechanical fuel pump for sbc

I've seen too many of all brands of mechanical pumps that had higher pressures than carbs can handle. And too many guys having flooding issues and rebuilding, or replacing carbs only to have the same issues still!
I also always install a fuel pressure gauge on all of my builds so I can easily see what the fuel pressure is at a glance. These issues don't just happen with cheap pumps, or old pumps; they happen regardless.

 

I get it and totally agree. I do the same thing but my point here is that this never used to be a problem with quality U.S. made parts when people took pride in their work. There are not many parts to a mechanical fuel pump, it seems that they could get the spring tension for the relief valve within specs.

 

Guess Edelbrock tech forgot about the internal valves in the pump ?

 

Stuck check valve.

 

Ya think ? Even after it runs good for about 10 minutes ? I mean I gotta believe uour right ,it's gotta be in the pump .the tank & feed line is out of the equation , the outlet line from pump to carb is new. Thanks ,I'm thinking of going with a higher psi pump ( 6-7, quickfuel or holley) .but still want to know wtf is causing this . Have a good one bud & thanks very much!!

 

I had the same problem with an Edelbrock fuel pump in my BBC. The first pump I used was a Summit unit, which worked fine but when I went to change the fuel inlet fitting that part of the casting broke off. Apparently a common problem with these pumps. Next up was the Edelbrock unit. I only had it for a few weeks when it started doing the same as yours, fuel pressure dropping from about 6 PSI to about 1 PSI. Was able to return this one to Summit and purchased a Carter pump which is still working great.

 

I've seen this before and my thinking is tolerances changing as the engine heats up and transfers heat to the pump body. If things are marginal clearance when cold, and then change with temperature it can cause this sort of problem.
I've seen this with some brands of pressure regulators also. Set them cold, and once they got heated from under hood temperatures the pressure drops 2-3 lbs. I try to mount my regulators down low towards the front of the frame rail so engine temps up higher wont affect them as much.

 

Thanks ,I'm not running a regulator , but I agree heat can change characteristics . The quick fuel carb suggest 6.5psi & for 2000 miles on build with the edelbrock ( never above 5psi) so I'm thinking get something 6-7psi & be done with it .but I'm opening it up cause I want to see what might be happening here .+ I'm done with edelbrock ,their customer service blows IMO . Thanks again!

 

Thanks I got 2000 miles on pump since new build .And I don't even know if it was new , NOT sure if it was used & put back on shelf at buddies cousins shop so..... we will C .I'm curious as to what's going on here .I m gonna search for clockable 6-7 psi pump either way .thanks again brother!

 

Carter M6900 as advised above.

 

YOU WERE RIGHT! sliver of aluminum holding check valve open . Thanks !

 

And to a degree at least, when some employers took pride in their employees.