Looking for fuel pump/pressure regulator advice

-
N

NukeBass

Well-Known Member
Joined
Apr 29, 2011
Messages
350
Reaction score
39
Location
Stanley, NC
[Brief background: I have a 73 duster with a 340, XE274H cam, Performer RPM manifold, and an Edelbrock Performer 1400 carburetor. I had the car restored at a local shop and I'm the guy who wanted a less powerful engine with a nicer idle. I will probably have the cam changed at some point, but haven't gotten that far yet, so I'm going to go through everything one piece at a time to make sure that switching the cam is the right decision for me and my "issues" with the car aren't due to a bad setup. Mike at MRL told me the car should be getting around 14-15" of vacuum at idle, and last I checked, it was getting around 11-12, so, I figure I will start checking things out.]

Edelbrock is pretty clear about requiring 6 psi or less for fuel pressure, so I checked that today. The engine builder's paperwork says I have a carter mechanical fuel pump, but no model number or anything. I rigged up a tee into my gas line and measured my fuel pressure just under 8 psig. I'm certain that this is my fuel pump: http://www.summitracing.com/parts/crt-m6270 I always wondered why this carburetor was running rich at idle (especially since it is supposed to be the leanest of lean carbs). I'm assuming the high fuel pressure would contribute to this?

So, I have two options as I see it: 1) Replace the fuel pump 2) Install a pressure regulator.

I'm leaning towards replacing the pump and am looking at this fuel pump on Summit http://www.summitracing.com/parts/crt-m6866 It says the pressure is between 5.5-6.5 psig so it should be compatible with the Edelbrock requirements. I could probably do this in about 8 hours (2 hours for normal people x 4 for me :) ) It might require some bending of the current fuel line, but I think I should be able to handle that. This seems to me to be simplest and potentially cheapest fix.

However, I do see the logic and reason behind keeping a higher flow fuel pump and having it regulated down to the required pressure. However, I have no idea how I would mount one and get it to work. Plus, the regulators (Quick Fuel and Holley) are more expensive than the OE style fuel pump.

I would like some opinions/experiences on what I should do to fix this problem. For the regulators, I would like to know how they were mounted and pictures would be great, if available.


Thanks!
 
I would just add a pressure regulator and gage on the inner fenderwell. Holley makes an inexpensive one then just dial the pressure down to 6 psi. Don't run gas into the passenger compartment. Leave the gage under the hood.
 
If you have too much fuel pressure the fuel should be overpowering the floats in the carb if that is the source of the rich condition. You would see fuel dribbling in the throat of your carb while idling. If you have a rubber fuel, (pressure of suction side of pump) you could pinch the line to restrict the fuel pressure to the carb even to the point that it completely blocks it momentary. Very soon you would see a smoother idle and higher vacuum IF the high fuel pressure is problem, that is until the fuel level in the carb drops way to low and the engine starts to stall. Many carbs will run will no problem at 8 psi but a few simple checks should get you pointed in the right direction.
 
If I do need a regulator, would you recommend using braided hose or running tube. I'm trying to envision how this will go.
 
I use a combination of 5/16 steel brake line if I want the threaded ends or just fuel line. I would not cut or alter your hard lines. My gage is just off a port on the regulator.
 
I have both pumps, the one on your car now needs a regulator.
You would have to plum it from the outlet of the fuel pump, to the regulator back to the carb. I would use braided lines.

The other pump that you posted a link to works well, and requires no regulator and will bolt right in.
 
You must log in or register to reply here.
-

Back
Top