Holley red pump pressure relief

[skip70]

Has anyone had any experience with these? wanting to adjust to max pressure 7psi.
Thanks

[GLENN 70]

Don’t bother and that pump is good for a Holden red motor . Most carbs don’t like anything over 6.5 psi . Volume is most important than high psi on carburettor engines . Fuel injection another thing .

[skip70]

I am running two of these in parallel but they wont give me more than 3.5lbs need 5lbs min at the regulator and I can tune from there. Will be going through the whole system for dirty filters as a matter of course. Just seeing if I should mess with these reds (and not just throw money at it) or replace with blues.

[AussiePhil]

Hey Skip,
Are you sure both pumps are running optimum, do you have check valves, they may be recycling!
Are you running them through a relay getting maximum current!
Cheers Phil.

[skip70]

Phil, have not checked them for flow or pressure individually as yet. No check valve in the set up, is this necessary? Yes relays on separate circuits. cheers

[AussiePhil]

Phil, have not checked them for flow or pressure individually as yet. No check valve in the set up, is this necessary? Yes relays on separate circuits. cheers

Hey Skip,
If one stops they could recycle, because they are vane pumps not as dramatic as centrifugal pumps, but fluid always flows to the least line of resistance.
Is this a new set up or has it just happened!
Check valves in parallel are always a good idea.
Are you sure one pump won't flow enough volume.

Cheers Phil

[AussiePhil]

Hey Skip,
I've just checked those pumps and they do have inbuilt check valves, so that's probably not the problem!
Although they sell a check valve rebuild kit!
Cheers Phil.

[AussiePhil]

Hey Skip,
Google, Holley Fuel Pump Relief Valve Sticking on youtube.
You'll find it may be the relief valve/s sticking.
Cheers Phil.

[GLENN 70]

You can take the bottom plate off and make sure the fins are all free moving . They can get stuck . What fuel line does it have from the tank to the engine bay ? ,3/8 or the small 5/16

[skip70]

Ok, can confirm plates off the bottoms of both pumps, checked screens (all clean) and made sure relief plungers were free moving, re-assembled. Replaced 5/16" pre pump filters with 3/8" ones and refitted assy's. Ran pumps individually now getting 5psi after regulator from both 
Tune and adjust later when not rushed for time. BTW 1/2" line from the outlets of both pumps to the regulator in the engine bay, oh and yes this is all new.
Thanks for the ideas boys.

[AussiePhil]

Hey Skip,
Great to here, onto the next job!
Cheers Phil

[GLENN 70]

Just be careful under full throttle that the fuel pressure doesn’t drop off with the 1/2 inch line . The fuel pumps have to be below the fuel outlet on the tank .  I run 3/8 line and a mechanical pump and that does the job ,but only a mildish 408 stroker around 520 hp at 6,000 rpm .  Just a Holley 770 vac sec .

[skip70]

Good Glen, will keep that in mind. Yes, pumps are below the outlets. thx.