The Ford Barn

19Fordy · 09-20-2022, 10:11 AM

I am currently using the Holley Fuel Regulator shown here:
https://www.amazon.com/Holley-12-803...a-568947600699
to control the fuel pressure from my electric fuel pump. It works fine.

However, over time the diafraghm inside the Holley regulator will fail creating a leak at the regulator. When this happens gas sprays out of the weep hole in the regulator creating a fire hazard. A photo of what I have now is below along with my proposed idea sketch. You can't tell if it's leaking when your inside the car. The current electric fuel pump is low pressure, the fuel pressure at the gauge is 4 psi and the carb. is a Holley 390 (List 8000, model 4160).
I am wondering if installing an adjustable petcock in the fuel line could be used to control the fuel flow in place of the regulator? Then, I could plug the weep hole in the regulator so it won't spray gas but would still allow gas to still flow through it to the carb when the diafragm fails OR I could just remove the regulator and rely on the petcock.

Your thoughts are appreciated. Thanks

marko39 · 09-20-2022, 10:36 AM

There is no reason I can see why it wouldn’t work. Any valve partially closed will create a pressure drop. Might want a gauge past valve to know what pressure you have.

5851a · 09-20-2022, 10:41 AM

Ford did something similar to the carbed 460's that came with a low-pressure electric pump in the 80's. Was in the carb feed line, looked like a inline filter and also return port, possibly to help with vapor lock. The engines had Holley's on them and no fuel pump on engine. Interesting set up.

69a · 09-20-2022, 02:02 PM

You cannot use a petcock because you don't have a constant flow of gas! If you set the pressure at idle you will run out of gas on the highway!

petehoovie · 09-20-2022, 02:17 PM

Quote:

Originally Posted by 19Fordy

I am wondering if installing an adjustable petcock in the fuel line could be used to control the fuel flow in place of the regulator?
Your thoughts are appreciated. Thanks

vincent · 09-20-2022, 04:07 PM

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Of course the petcock will not work. As soon as you need a different amount of fuel, you need a different setting on the cock.

RKS.PA · 09-20-2022, 04:38 PM

I have a Mr. Gasket 9710 adjustable fuel pressure regulator on my SBC 283...sorry my '47 runs off the mechanical pump just fine, so doesn't need the pressure reduced.

I've had this regulator for years and so far, no ruptured diaphragm! Guessing I may have been lucky.

Seems like your solution is a better or different regulator??

hotcoupe · 09-20-2022, 04:40 PM

I know this is not the question that you asked but, If I were you I would use a fuel pressure regulator made by "Malpassi". I put one on my '37 1/2 ton years ago, ACCURATE, fully adjustable, never a bit of trouble.
Tom

cadillac512 · 09-20-2022, 04:45 PM

How much pressure does your electric pump produce without the regulator? That Holley 390 carb should be happy with up to 7 lb. Maybe the reg isn't needed?

RKS.PA · 09-20-2022, 05:42 PM

Quote:

Originally Posted by cadillac512

How much pressure does your electric pump produce without the regulator? That Holley 390 carb should be happy with up to 7 lb. Maybe the reg isn't needed?

Wouldn't that be the best solution of all!!! I had a 390 on my '39 flathead without a regulator and it worked just fine.

Ggmac · 09-20-2022, 06:17 PM

A valve won’t cut it , as posted above , different rpms require different volume of fuel . Earlier there’s a post about a member chasing a stumbling problem, it turned out to be a semi blocked check valve in the fuel pump to carb line . Thats what youll be creating. I’d run with out the regulator and see if it pushes past the needle and seat . Another more involved possible solution could be to tap the vent and run a hose down to a catch can you would see or smell .

19Fordy · 09-20-2022, 06:24 PM

THANK YOU all for the very helpful suggestions.
The present fuel pump is for 4-7 psi so perhaps I really don't need a pressure regulator.

SoCalCoupe · 09-20-2022, 09:50 PM

Quote:

Originally Posted by 19Fordy

I am currently using the Holley Fuel Regulator shown here:
https://www.amazon.com/Holley-12-803...a-568947600699
to control the fuel pressure from my electric fuel pump. It works fine.

However, over time the diafraghm inside the Holley regulator will fail creating a leak at the regulator. When this happens gas sprays out of the weep hole in the regulator creating a fire hazard. A photo of what I have now is below along with my proposed idea sketch. You can't tell if it's leaking when your inside the car. The current electric fuel pump is low pressure, the fuel pressure at the gauge is 4 psi and the carb. is a Holley 390 (List 8000, model 4160).
I am wondering if installing an adjustable petcock in the fuel line could be used to control the fuel flow in place of the regulator? Then, I could plug the weep hole in the regulator so it won't spray gas but would still allow gas to still flow through it to the carb when the diafragm fails OR I could just remove the regulator and rely on the petcock.

Your thoughts are appreciated. Thanks

19Fordy,

I have the exact same pressure regulator in my 1941 coupe. Of course I don't want to have the failure you describe in my car. What information do you have about the diaphragm that it "will fail." Does it always fail? When? Why?

Thanks! Any insights are welcome.

Brad

fordor41 · 09-20-2022, 10:14 PM

a valve controls flow not pressure.

19Fordy · 09-21-2022, 09:16 AM

SoCalCoupe:

My experience has been that after a year or two, the diaphragm inside the Holley fuel pressure regulator becomes brittle and leaks where the diaphragm is crimped to the metal spring loaded disc inside the regulator. Gas then seeps through the diaphragm into the area above the diaphragm and out the weep hole. I am thinking that today's gas is not compatible with the diaphragm material.

The present (black) diaphragm used in the 803 regulator is Part # 12-807.
There is also Part #-35-1100QFT (green) that is resistant to the corrosive effects of today's gas. Using that diaphragm is the way to go, I think. Look here:
https://www.holley.com/products/fuel...r_repair_kits/

cadillac512 · 09-21-2022, 04:52 PM

Quote:

Originally Posted by 19Fordy

THANK YOU all for the very helpful suggestions.
The present fuel pump is for 4-7 psi so perhaps I really don't need a pressure regulator.

Bet you don't. I've run a lot of Holley 4150/4160 carbs at 7 lbs with no problem at all. Give it a try...my bet is it'll be just fine. Holley rates that carb to handle that pressure.

mike42 · 09-21-2022, 05:39 PM

Fordy …..Holley makes a 1 to 4 psi reg. 12-804. I had a problem last year that in some Holley Regs they put in the wrong spring which caused too much pressure. I replaced the spring and no problems or leaks. I have a gauge and it stays at 2.7 psi. I had other problems but found out it was a bad check valve in a fuel line.

Mike

19Fordy · 09-21-2022, 06:19 PM

Again, THANKS to all for the great advice based on life's experience.

glennpm · 09-22-2022, 06:54 AM

Hi Jim,

I posted a modification that I did on a Holley 12-804 regulator. which regulates from 1 to 4 psi If there is leakage in the diaphragm, a 1/4" brake line with connected hose, dumps it below the motor. This is the old thread which you liked at the time! Pics from my mod and the ref thread are below.

https://www.fordbarn.com/forum/showp...0&postcount=30

https://www.fordbarn.com/forum/attac...6&d=1481739963

glennpm · 09-22-2022, 09:33 AM

Note that I left the casing notch open (see notch in the third picture above) so that atmospheric pressure above the diaphragm would function well. It could be closed easily by grinding the top off underneath the adjusting nut or filling with epoxy. Atmospheric pressure would then be reduced due to pressure drop over the length of the drain hose attached.

Glenn

09-20-2022, 10:36 AM	#2
marko39 Senior Member Join Date: Oct 2016 Location: harpursville ny Posts: 1,040	Re: Fuel Regulator Idea and Question There is no reason I can see why it wouldn’t work. Any valve partially closed will create a pressure drop. Might want a gauge past valve to know what pressure you have.

09-20-2022, 10:41 AM	#3
5851a Senior Member Join Date: Oct 2014 Location: NE Iowa Posts: 1,664	Re: Fuel Regulator Idea and Question Ford did something similar to the carbed 460's that came with a low-pressure electric pump in the 80's. Was in the carb feed line, looked like a inline filter and also return port, possibly to help with vapor lock. The engines had Holley's on them and no fuel pump on engine. Interesting set up.

09-20-2022, 02:02 PM	#4
69a Senior Member Join Date: Aug 2020 Posts: 144	Re: Fuel Regulator Idea and Question You cannot use a petcock because you don't have a constant flow of gas! If you set the pressure at idle you will run out of gas on the highway!

09-20-2022, 04:07 PM	#6
vincent Senior Member Join Date: Jun 2020 Location: Germany Posts: 204	Re: Fuel Regulator Idea and Question Sponsored Links (Register now to hide all advertisements) Of course the petcock will not work. As soon as you need a different amount of fuel, you need a different setting on the cock.

09-20-2022, 04:38 PM	#7
RKS.PA Senior Member Join Date: Jun 2010 Location: Marana, AZ Posts: 1,194	Re: Fuel Regulator Idea and Question I have a Mr. Gasket 9710 adjustable fuel pressure regulator on my SBC 283...sorry my '47 runs off the mechanical pump just fine, so doesn't need the pressure reduced. I've had this regulator for years and so far, no ruptured diaphragm! Guessing I may have been lucky. Seems like your solution is a better or different regulator??

09-20-2022, 04:40 PM	#8
hotcoupe Senior Member Join Date: May 2010 Location: imperial,mo Posts: 694	Re: Fuel Regulator Idea and Question I know this is not the question that you asked but, If I were you I would use a fuel pressure regulator made by "Malpassi". I put one on my '37 1/2 ton years ago, ACCURATE, fully adjustable, never a bit of trouble. Tom

09-20-2022, 04:45 PM	#9
cadillac512 Senior Member Join Date: Apr 2019 Location: Kansas Posts: 921	Re: Fuel Regulator Idea and Question How much pressure does your electric pump produce without the regulator? That Holley 390 carb should be happy with up to 7 lb. Maybe the reg isn't needed? __________________ "It don't take but country smarts to solve the problem" (Smokey Yunick) '41 Merc Town Sedan / 260" 8CM engine '66 Fairlane four door / "warmed up" 302

09-20-2022, 06:17 PM	#11
Ggmac Senior Member Join Date: Jul 2016 Location: Lake worth Florida Posts: 1,088	Re: Fuel Regulator Idea and Question A valve won’t cut it , as posted above , different rpms require different volume of fuel . Earlier there’s a post about a member chasing a stumbling problem, it turned out to be a semi blocked check valve in the fuel pump to carb line . Thats what youll be creating. I’d run with out the regulator and see if it pushes past the needle and seat . Another more involved possible solution could be to tap the vent and run a hose down to a catch can you would see or smell .

09-20-2022, 06:24 PM	#12
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,925	Re: Fuel Regulator Idea and Question THANK YOU all for the very helpful suggestions. The present fuel pump is for 4-7 psi so perhaps I really don't need a pressure regulator.

09-20-2022, 10:14 PM	#14
fordor41 Senior Member Join Date: Oct 2011 Location: elmira,ny Posts: 1,516	Re: Fuel Regulator Idea and Question a valve controls flow not pressure.

09-21-2022, 09:16 AM	#15
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,925	Re: Fuel Regulator Idea and Question SoCalCoupe: My experience has been that after a year or two, the diaphragm inside the Holley fuel pressure regulator becomes brittle and leaks where the diaphragm is crimped to the metal spring loaded disc inside the regulator. Gas then seeps through the diaphragm into the area above the diaphragm and out the weep hole. I am thinking that today's gas is not compatible with the diaphragm material. The present (black) diaphragm used in the 803 regulator is Part # 12-807. There is also Part #-35-1100QFT (green) that is resistant to the corrosive effects of today's gas. Using that diaphragm is the way to go, I think. Look here: https://www.holley.com/products/fuel...r_repair_kits/ Last edited by 19Fordy; 09-21-2022 at 09:23 AM.

09-21-2022, 05:39 PM	#17
mike42 Senior Member Join Date: Jun 2012 Location: Gaylord, Michigan Posts: 1,599	Re: Fuel Regulator Idea and Question Fordy …..Holley makes a 1 to 4 psi reg. 12-804. I had a problem last year that in some Holley Regs they put in the wrong spring which caused too much pressure. I replaced the spring and no problems or leaks. I have a gauge and it stays at 2.7 psi. I had other problems but found out it was a bad check valve in a fuel line. Mike

09-21-2022, 06:19 PM	#18
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 10,925	Re: Fuel Regulator Idea and Question Again, THANKS to all for the great advice based on life's experience.

09-22-2022, 06:54 AM	#19
glennpm Senior Member Join Date: Sep 2014 Location: Wiscasset, Maine Posts: 1,981	Re: Fuel Regulator Idea and Question Hi Jim, I posted a modification that I did on a Holley 12-804 regulator. which regulates from 1 to 4 psi If there is leakage in the diaphragm, a 1/4" brake line with connected hose, dumps it below the motor. This is the old thread which you liked at the time! Pics from my mod and the ref thread are below. https://www.fordbarn.com/forum/showp...0&postcount=30 https://www.fordbarn.com/forum/attac...6&d=1481739963

09-22-2022, 09:33 AM	#20
glennpm Senior Member Join Date: Sep 2014 Location: Wiscasset, Maine Posts: 1,981	Re: Fuel Regulator Idea and Question Note that I left the casing notch open (see notch in the third picture above) so that atmospheric pressure above the diaphragm would function well. It could be closed easily by grinding the top off underneath the adjusting nut or filling with epoxy. Atmospheric pressure would then be reduced due to pressure drop over the length of the drain hose attached. Glenn