Fuel pump/line question

[charger1972]

So, my 512 stroker isn't done yet but i know I'm gonna have to upgrade fuel system. Removed the fuel cell last year and installed a tank that i welded a sump into. The Holley electric pump cant pull fuel up the line so it has to be level for it to work. Did a search on here and there was mention of a check valve to keep the pump from going dry. My old Holley isn't going to cut it so was looking at a couple other ones that will. The biggest problem with the line being level is the pump has to be mounted way low, and if i wanted tail pipes the line is in the way. Any in put would be appreciated as allways ,thanks.

[charger1972]

Anyone? No one running a sump ? Ron (firefighter3931) , whats your setup? All ready have a 1/2 inch return from bypass regulator. Was thinking 1/2 inch feed with this pump .....http://www.jegs.com/i/Holley/510/12-1400/10002/-1?parentProductId=   . Any thoughts? Like i said before, main concern is if it will pull fuel up the line so the feed isn't  pointing level and the pump doesn't have to be mounted so low.

[Cooter]

I run twin Holley blues on the Dart with no problems with priming.
I'd move that pump up and out the way, with the check valve. I've seen some homemade check valves made from a steel ball in a brass fitting. You COULD try using what I call the "S trap" where the braided line is positioned like the "S" trap under your sink to keep enough fuel at the pump where when turned on, siphon effect takes over.

[charger1972]

Cooter, the single Holley I'm running wont pull fuel up the line. Maybe its toast. I have rebuilt it from other pumps,pressure is good but just wont pull fuel up hill unless primed first. Check valve is a definitely thing on my list. And yeah, want to mount the new pump higher and out of the way. Thanks for the input.

[Cooter]

I assume you've checked the screen filter in the pump?

[charger1972]

Oh yeah, very familiar with the pump, have had it apart many times. Even bought a Chinese version that lasted a week. Even if it worked properly , wont be enough for my build right? 512 cubic inch 850 cfm carb .

[Cooter]

Well, I always error on the side of caution when dealing with fuel systems. Meaning I always like to have too much.
Id he lookin into the Holley Blue or black series  .  With a regulator set at around 7 psi.

[firefighter3931]

Hi James,

I'm running a Mallory 250 and have the pump mounted right next to the cell in the trunk. Originally I had the pump mounted in the shock tower area but the pump had to pull fuel fuel 4ft up from the sumped tank (like yours) and it was not ideal. These pumps are designed to be gravity fed. 

The pump location you're using will work fine but I would use a Mallory140. The return line should not be plumbed into the sump....it should be dumped into the top of the tank. 



Ron

[charger1972]

Hey Ron, running the return into the sump is bad? Whoops, another thing to change. But the thing is, i don't want the pump where it is now. IF i run tails its right in the way. And think it`s to low , if i move it up like you did have, i know you said its not ideal but if i use a check valve think it will be ok? And Cooter, i like your thinking. Overkill is all ways better.

[firefighter3931]

Hey Ron, running the return into the sump is bad? Whoops, another thing to change. But the thing is, i don't want the pump where it is now. IF i run tails its right in the way. And think it`s to low , if i move it up like you did have, i know you said its not ideal but if i use a check valve think it will be ok? And Cooter, i like your thinking. Overkill is all ways better.

James,

The return line into the sump is a big no-no  It creates too much turbulance on the suction side due to the close proximity. 

The problem with running a full exhaust using tailpipes in the factory location is that it limits fuel pump placement. These pumps should be mounted at the same level (or lower) as the sump. The pump is not designed to pull fuel up and too far forward of the sump/suction location. This is the problem i was encountering with mine so i decided to go with the cell and mount the pump right next to it. 

Also it's very important to use a very low restriction fuel filter between the sump and pump. I use a 100 micron filter before the pump inlet and a 40 micron filter on the discharge side. Too much restriction on the inlet will cause the pump to overheat and cavitate.



Ron

[charger1972]

Thanks Ron, no tails then. I like it loud anyway  .

[charger1972]

Ron, just looked up the Mallory 140 , says 3/8 in/outlet . Is that enough ? Thought i was going to have to change to 1/2 inch supply line . Just making sure before i order, thanks.

[firefighter3931]

Ron, just looked up the Mallory 140 , says 3/8 in/outlet . Is that enough ? Thought i was going to have to change to 1/2 inch supply line . Just making sure before i order, thanks.

Hi James, the outlet/inlet are 3/8 npt....I would use -8 braided line with the appropriate adapters. 


Ron

[charger1972]

Thanks Ron. 

[firefighter3931]

James, here is a link to the filters i used. The smaller version would work fine with the Mallory 140 pump and it comes with 3/8npt threads. You would also need fittings to adapt the filter onto your mallory pump. I mounted mine right to the pump....one on the inlet, the other on the discharge side. Robb has a source for the fittings so if you decide to plumb it up that way make sure to let him know. I used a low restriction 100 micron as a pre-filter and 40 micron on the discharge before the regulator/carb.

Robb used to work for Mallory as an engineer and is very familiar with their products. His stuff is top shelf 


http://www.robbmcperformance.com/products/filters.html


Ron


PS. Below is a pic of a Mallory 250 with the filters mounted directly to the pump assembly. Makes for a clean installation. 

[charger1972]

Thanks for the tip Ron, pretty cool filters. 

[firefighter3931]

Thanks for the tip Ron, pretty cool filters. 

Very nice James....that'll get r done ! 


Ron