Quality, reliable mechanical fuel pumps

[Cadman-iac]

  Who makes a decent mechanical fuel pump for a small block Chevy?
 I'm currently using a Carter large can pump with a return port on it, and when it gets extremely hot the pressure drops off to almost nothing. It still puts out enough to keep the engine running, but just barely.  It puts out up to 9 psi cold, and will maintain around 4 to 5 psi most of the time, but  during the heat of the day (100° plus) under a load, such as pulling a trailer and using the air conditioning, the pressure drops to as low as 1-2 psi at idle, but does pick up to about 3 to 3.5 psi at higher RPM's.
 I thought about using a pump without a return port, but that would just increase the likelihood of a vapor lock.
 I clamped off the return line to see what if any difference it would make and the pressure only increased by 1 psi.

 What kind/ brand of pump are you running on your small block, and how well does it handle the heat? Do you have to boost it with an electric pump?

 I know I'm operating in extreme conditions, but there must be a pump that can handle the heat, right?

 If you are backing up your mechanical pump with an electric pump, what kind are you using, and how well does it do?

 The electric pump I'm currently using as a backup is one that looks kinda like a fuel filter with wires, it's a solenoid style. It won't increase the pressure to normal, but does bring it up 1 to 2 psi in this extreme heat.

  Rick

[quadrajam]

I fought this same demon for years. Engine heat boiling the fuel in the pump. The key
is having sufficient bypass flow to displace the boiling fuel with cooler fuel from the tank.
 
 In answer to your question I don't think there is a high performance 3 port fuel pump.
You may need to use a performance pump, 80-100 GPH and come up with your own
return bypass petween the pump and carb.
  Is your existing return to the tank free and unrestricted?

I finally had to revert to an in-tank pump and return line with a bypass regulator
under the hood. No more problems. I really wanted to keep my mechanical pump.
I HATED the idea of an in tank pump. I even passed on a really good deal on
a 880 block because of no fuel pump provision.

 QJ

[lightning boy]

RobbMC makes a nice mechanical fuel pump. Not cheap though.

[quadrajam]

I just googled it. Thats a nice pump AND it has a bypass port.
That may be your ticket Cadman. Had I known about it I may have....hmmmm..
too late now,gone electric.

QJ

[Cadman-iac]

I fought this same demon for years. Engine heat boiling the fuel in the pump. The key
is having sufficient bypass flow to displace the boiling fuel with cooler fuel from the tank.
 
 In answer to your question I don't think there is a high performance 3 port fuel pump.
You may need to use a performance pump, 80-100 GPH and come up with your own
return bypass petween the pump and carb.
  Is your existing return to the tank free and unrestricted?

I finally had to revert to an in-tank pump and return line with a bypass regulator
under the hood. No more problems. I really wanted to keep my mechanical pump.
I HATED the idea of an in tank pump. I even passed on a really good deal on
a 880 block because of no fuel pump provision.

 QJ

  I hate the idea of an electric fuel pump as well, which is just one of the reasons why I removed the original one from the tank.
 This used to have a throttle body system on it but wouldn't work with the roller cam, thus the carb and mechanical pump.

 So which fuel pump did you finally choose, and what regulator are you using?
 There's so many to choose from I honestly don't know where to start, and trial and error can get expensive.

 If I have to go back to an in-tank pump though, at least it's already wired for it.
 

RobbMC makes a nice mechanical fuel pump. Not cheap though.

 Yeah, not cheap, but not totally outrageous. My question is how long have these guys been in business? And a 90 day warranty is a bit short for what you're paying.  Has anyone here bought and used one of these,  what's your experience with it?

  Rick

[Cadman-iac]

  Looking at this Robbmc website, they're recommending that you use a vented gas cap, but they are assuming you are racing. They also mention using a "cool-can,"  and wrapping the fuel lines.
 A vented cap isn't going to work for a vehicle on the street, your vapor recovery system won't work properly.
 Wrapping the lines is impractical, mainly because on a street-driven vehicle the heat build-up would overcome any advantage wrapped lines would give you, that's a quarter mile at a time solution.
 And using a cool-can you would have to add ice every 10 miles or less.
 So what actual advantage would you have by using one of these pumps if it requires all these other tricks to overcome your low fuel pressure problem for short distances?

 I need a solution for long distances in excessive heat. Am I looking for a unicorn?

[quadrajam]

My truck is a 92 s10 that was originally a 4.3 v6 with TBI. Now has a near stock
carburated 355 v8. I used a parts store replacement in-tank for the 92 s10.
The regulator is a Holly 12-887 mounted on the AC evap box. The pump outputs
 about 12-15 psi and the regulator is set @ 6 1/2 lbs. Also ran new lines while I was at it.

I slid some insulation tubing over the lines under the hood and just behind the engine
although there wasn't any issues with heat, I just did it anyway.

I ran a fuel pressure gauge on the dash for years during the mechanical pump/crappy
gas fiasco. Now there is 6 psi all the time and I finally got rid of the gauge.

There may be better choices for the pump and regulator. Not my area of expertice
but I got lucky and it worked first time. Been about 3 months & 2500 miles, no problems.

QJ

[tayto]

best thing i did for my Qjet was put an intank pump in my squarebody. the fact you had an electric pump from the get go and removed it is wild.

[77cruiser]

That's what I thought when I put an in tank in my Monte.

[Brian B.]

RobbMc.