fuel pressure regulator

[Tommy]

When I pulled the leaky Holley 1920's for my P12 I noticed that the PO had used gobs of sealant around the float bowl gaskets.
The car is equipped with a 6V electric fuel pump mounted in the rear near the tank. What it doesn't have is a fuel pressure regulator.
I'm not sure what pressure the pump is putting out, but I am sure it is more than necessary by a considerable amount.
I have decided to install a FPR with a gauge. I hate to cut up the purdy hard fuel lines to install it, but I hate fuel leaking on the exhaust manifold a lot more.
I am guesstimating that around 6 psi would be about right?
TIA
 

[Robert Horne]

Years ago when I first installed my electric fuel pump, it would shut off at 5 psi.

I had installed a "T"  with a pressure gauge in the line near the engine compartment,

just to view the fuel pressure from time to time.  Pressure ran 5 psi.

A year later the pump runs all the time when turned on.  6 psi now..

 

Two old pumps I have will shut off at 3psi ....

[Plymouthy Adams]

4-51/2 lbs

[knuckleharley]

I'm thinking 4 psi would be plenty. It ain't like you are trying to feed 500 hp at 6,000 rpm. I run 5-6 lbs fuel pressure on OHV V-8 street engines with lumpy cams,high rise intakes,and dual feed 650 carbs,and never seem starved for fuel. One is a balanced and blueprinted 412 small block with 7,000 RPM cam,roller rockers,gear drive,10 to 1 flat top pistons,gapless rings."long" rods,and ported and polished big valve  heads. The rod straightening,balancing,and block assembly was done by a NASCAR engine shop using special order Keith Black pistons so I could use 350 rods in a 400 block. That thing is border line scary in a 3,500 lb street car. If it can live with 6 psi fuel pressure,your flat 6 Mopar will be fine with 4 psi.

 

You can buy adjustable fuel regulators from people like Summit or Jegs. Buy one and make up a custom line from the chassis up front to the carb,with the adjustable fuel pressure regulator up top near the gas inlet so you can see and adjust it.

 

If the carb mating surfaces are warped from over-tightening,you can fix this with a pieces of emory or sand paper on a pane of glass. Just gently slide the mating surfaces back and forth on the glass until all the contact areas are shiny. Use a new gasket,put it back together,and the problem is solved.

 

UNLESS your threads are slopped out from over-tightening,when is fairly common. Take care to notice if the screw fit feels sloppy when backing them out,and even check by tightening them up and juding by "feel" if they snug up nicely,or you have to apply some torque to get them to bottom out.

 

If you have these problems,get a screw gauge (hardware store,NAPA,etc) to determine what size and thread count screws you have,and then buy a Heli-Coil repair kit. It will contain everything you need but the new screws to tap your base holes out to a larger size,and a  Heli-Coil insert and tool to screw the proper size Heli-Coil into the newly tapped hole, I just bought a 10-32 Heli-Coil thread repair kit for my 51 Ford from Amazon for around $26 delivered. Seems like parts stores are now selling them for $30-45,depending on size. The standard 1/4 inch to 3/8 inch are generally a little cheaper than the machine size insert kit you will need.

Edited December 23, 2015 by knuckleharley

[Phil Martin]

When I put 6 volt pump on my dodge I checked fuel pressure at 16 lbs. Put a regulator on it for sure.

[48mirage]

I run a holley 94 on my 230 motor.  That particular holley didn't like the pressure from the OEM pump.  I went down to the local parts store and got a pressure regulator (Mr. Gasket, I think) and dilaed it down to 2.5 psi.  Works great now.

[Jerry Roberts]

Most vacuum gauges have a side for measuring pressure too .