whats the ideal Fuel line setup for triple carbs?

[zKars]

Have to wade in here with some personal experience with triples and fuel pumps and regs.

First piece of advice on return style regulators. Read the spec sheet!!

I put in a new Mallory fuel pump and that Holley 12-804 reg and all was fine; For a while. Pump was a little noisy, but tolerable. One day about 25 hours of run time, the pump just plain quit. Took it out, and on the bench it would run for a while, then quit. Let it sit, try again, same thing; run, not run, run, not run, pumping water into and out of a bucket. Okay, must have burned it up. What's next....

"I'm gonna do it right" (famous last words) I went out and bought a Mallory 4309 return style reg (1-4 PSI), plumbed it with with 6AN hose all the way to tank. I welded AN fittings on the tank outlet, and return lines, even used the front vent tube instead of the intended return line tube, as its diameter is about the same as the outlet tube, about 1/4-5/16" IIRC.

It ran, but could not get the pressure to stabilize. Try all kinds of things. The pressure would stay up, then over about 15 minutes, it would fade off to nothing, stranding me! Sit for a while, fires back up, just make it home before it dies again. NOW WHAT!!! ArRRRGGGG!

Finally read the instructions. (imagine that).

"Mininum 3/8 ID hose (8AN) to and from the tank for pumps upto 100 GPH, 1/2 hose above that!!!!".

No way what I had was going to work with the smaller than 3/8 ID tubes at the tank, no matter what size hose you want to use. Choke!

With nothing that "worked", I stuck a mechanical style pump back on the head so I can get around until I figured out what's going on. Well I'll be damned if that car didn't run like a champ, and QUIET, at any throttle setting you wish to push to. I am still running that stock mechanical pump... Have nice stainless AN stuff going into to those 1/8NPT fittings on that pump too. Real purdy...

Did I mention I have triple 44 Mikunis and 3.1 stroker to feed?

Oh, and I have a really nice Mallory fuel pump and return style reg for sale if any one needs one... Its' going real cheap....

Jim

PS. Did this last spring just before a car show. I get there and start talking to a buddy from out of town about my whoas trying to get to the show.

Wouldn't you know, he tells me almost the identical story about his efforts to get a fuel system to work. I ain't alone....

[overdrivex]

my heads dont have a spot for mechanical pump. would put the n47 head i have on but i know for a fact that the longblock in the car works great. while he longblock with the n47 are questionable. but none the less im going with dellorto manufactures recommendation. since im in houston i might see about getting a booster pump because of the hot humid conditions here. but... im going to wait and see if its even a issue before i start adding unnecessary items.

[overdrivex]

figured i use the old fuel rails as my vacuum lines for my carbs/manifold/and carbon filter setup.

mabe fixitman can chime in on this question. what did you hook the purge line on the carbon filter to in your carb setup?

Edited April 12, 2009 by overdrivex