You don't really need check valves if the pumps you install have
sufficient flow--the resistance to flow of a idled second pump will be
plenty. Many pumps have check valves built in--it's how they work. Two
pumps of any type is a really good idea--saved a race for me several
times. I use the cheap, adjustable chromed regulators that you can get
anywhere and have a pressure gauge just before the carbs that I can see
from the driver's seat. Any sign of pressure drop and I can turn on the
second pump.
-----Original Message-----
From: Russ Moore [mailto:rem9@sunlink.net]
Sent: Saturday, August 09, 2003 9:19 AM
To: Henry Frye; fot@autox.team.net
Subject: RE: Fuel Pumps
I've had excellent luck with Facets over the years.
Russ
-----Original Message-----
From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net]On
Behalf Of Henry Frye
Sent: Saturday, August 09, 2003 9:59 AM
To: fot@autox.team.net
Subject: Fuel Pumps
I have been playing with the idea of running dual fuel pumps for a while
now. If I drop in a second pump, I assume I need a pair of check valves so
I don't backfeed the cell through a non-operating pump. True? What check
valves should I use?
I have been fighting fuel problems ever since I changed out a little Facet
cube pump and an el-cheapo fuel pressure regulator for a Holley Blue Top
pump and a Holley regulator. My fuel pressure gauge would show an
intermittent fluttering accompanied by a distinct buzzing coming from the
regulator. I swapped the regulator, I tried both the 1 to 4 PSI and the
4.5 to 9 PSI regulator that comes packaged with the fuel pump. Both did
this from time to time with the engine running or not. At Mosport I had
things running pretty well (with notable exceptions!) but running the
Triumph feature I found some times the car would take full throttle
happily, and some times it seemed to bog down at anything more than 4/5th
throttle.
So I decided to replace the fuel delivery system from the pump to the
carbs. I ran new 3/8th's inch hard line from the pump to the new
regulator. While I had the pump in hand, I decided to drop the bottom off
and take a look.
The pump is of the basic rotor and vane variety, the rotor sits off-center
in the round pump bore, and 4 little vanes slide in slots in the rotor. As
the rotor turns each vane slides in and out of it's slot, remaining in
constant contact with the bore. Centrifugal force at play here.
I found the pump cavity as clean as I could have hoped for, the debris
screen was perfectly clean. I spun the rotor by hand, and I found my
smoking gun. One of the vanes was stuck in it's slot. It easily became
unstuck with a tiny amount of encouragement, but no doubt the vane was not
doing what it was supposed to. Holley sells a rotor and vane replacement
kit, which I installed, but I have lost all confidence in the design of
the pump. I see no reason for this failure to have happened. The rotor and
vanes I removed from the pump look fine, and the vanes slide freely in the
slots. Perhaps something in the race fuel???
Any recommendations on fuel pumps OTHER than Holley?
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