Reducing fuel pressure

[K Crone]

Has anyone here successfully reduced mechanical fuel pump pressure by shimming the pump? Thanks

[ford38v8]

I don't think that would reduce pressure, but likely would reduce flow. I think I know where you're coming from on this... You replaced your pump or rebuilt the old one, but now have higher pressure? The new pumps and kits have stronger springs than original, so the best way is to remove the new spring and put in the old original.

[Charlie ny]

The spring is the thing. My method is so rube goldberg but I'll pass it on. When a pump is putting out too much psi I remove the spring and using that spring compress it against

another spring from my stash. I'll find a weaker one every time and hit my 2 1/2 to 3 psi

in 2 or 3 tries.
Charlie ny

[tubman]

Charlie, what are you going to do when your "stash" runs out? Could you get the same effect by shortening the spring?

[Will D]

I have never tried shimming the pump stand to decrease pressure but have read other threads on hear saying it is possible.

When I rebuilt mine I just used the old springs. Here's a pic for visual comparison.

[Charlie ny]

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Shorter works sometimes, same length weaker is my comfort level....My stash...
Red Hamilton sold me 2 big boxes of cores...then Dan Krehbiel within a month sold me
two more boxes. Original, replacement, after market you name it. I build 250 pumps a year on average....so I'm set for 3 more years.....if I live that long.
Charlie ny

[Zeke3]

Originally Posted by Charlie ny

Red Hamilton sold me 2 big boxes of cores...then Dan Krehbiel within a month sold me
two more boxes. Original, replacement, after market you name it. I build 250 pumps a year on average....so I'm set for 3 more years.....if I live that long.
Charlie ny

I guess this means that you wouldn't be interested in a few more cores then.

[Charlie ny]

Zeke,
I'm still looking but selective.....the original '36 - '40 non glass bowl with the inlet and outlet at 3/16 - 1/4 different heights.
Charlie ny

[K Crone]

My motor is in the process of being rebuilt so i can not test right now.

[K Crone]

Can i get some photos of how you guys set up your fuel line pluming.

[K Crone]

I need help getting enough posts so i can DM.

[Mart]

Well put a few responses on here or on other peoples posts. It's designed to weed out the badduns.

Fwiw I have fitted old springs into new pumps before now.

[Will D]

Originally Posted by K Crone

I need help getting enough posts so i can DM.

Your almost there. 4 more posts.....

What color is the vehicle your working on?

[Will D]

Originally Posted by K Crone

Can i get some photos of how you guys set up your fuel line pluming.

[K Crone]

The car is a hand brushed satin black 29 roadster

[K Crone]

Where did you source your fittings i need 5/16 flared fitting for my firewall mounted fuel filter

[K Crone]

Looks like you have a comb of flared fittings and compression. Is that 5/16 line or 3/8

[Mart]

K, Most Ford carb setups use 1/4" fittings. The carb and fuel pump take the same "ford" nuts and a 1/4" olive (ferrule?). Using anything different makes things more difficult.
Hey, 10 posts. Way to go.

[K Crone]

Yeah

[Will D]

Originally Posted by K Crone

Looks like you have a comb of flared fittings and compression. Is that 5/16 line or 3/8

The fuel line is from Third Gen Auto, 1/4" copper plated steel, comes with one piece nut/ferrule fitting on each end. The pressure gauge i just teed in with compression fittings from the hardware store. I couldn't find the right tee to accept ferrule/nut as well as adapt to the gauge fitting so I just did what I could with what i had and was readily available.

5/16" brake line flare fittings(1/2×20 thread if i remember correctly) fit in both the carb inlet and fuel pump outlet. I have successfully used these 5/16" fittings with a 1/4" ferrule on 1/4" copper pipe while messing around in the shop, connecting gas can to carb and such.

You could always use the 5/16" brake line fitting with flared 5/16" steel pipe? Not sure if that would affect flow rate.

Mart is right, its a lot more messing about....but if you have more time than money and random parts lying around waiting to be used