Fuel pressure regulator

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AZScott
Posts: 105
Joined: Mon Aug 15, 2016 11:57 am
Location: Tucson, Arizona

Fuel pressure regulator

Post by AZScott »

I am currently running a Purolator Pro-Fuel regulator (set at 3.5) with an electric pump on a turbo motor running a ’65 Carter YH carburetor, (75-1654 metering rod, and .094 jet). I have read that the Pro-fuel regulators are not reliable.

I would like to know if anyone had any experience or advice on this setup and what should the pressure be set at. I am not sure if my setting is too low. My preference would be to find a more reliable regulator, so I would be interested if there is any advice from the forum on if I should upgrade and which one I should go with.
Thanks
63 Monza Coupe (164-4 carb)
64 Spyder Convertable
62 MGA Roadster
74 Norton Commando
69 Triumph Bonneville
66vairguy
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Joined: Tue Dec 21, 2010 3:44 pm

Re: Fuel pressure regulator

Post by 66vairguy »

You should check out the corvaircenter forum. Steve Goodman posts there and has experience with this topic.

Years ago the club I'm in had an EM turbo Vair and the engine and fuel system were rebuilt. The car ran poorly and had horrible fuel mileage in spite of all attempts to "adjust" the carburetor. Steve Goodman (Rear Engine Specialists - Colorado) recommended a Holley fuel pressure regulator (don't mount it on the engine to avoid vibration issues) set to 2-3PSI at sea level elevations. A club project was to install the regulator on the body and route metal braided flexible hoses to the carburetor and set the regulator at 2.5PSI (using a precision gauge). Fixed all the problems, ran great and the mileage improved. Colorado has some higher elevations at which you reduce the fuel pressure to compensate.

Don't forget the turbo carburetor was revised several times and you can find a mismatch of parts that can cause problems. If in doubt contact Steve about rebuilding your carburetor to spec.
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bbodie52
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Re: Fuel pressure regulator

Post by bbodie52 »

Holley manufactures quite a few fuel pressure regulators, but most have a range of 4.5 - 9 psi or higher, or are designed for a fuel injection system. This unit has the correct range and apparently a good reputation...

CHROME CARBURETED FUEL PRESSURE REGULATOR
Street/Strip Carbureted Applications
Two Port
Adjustable from 1 to 4 PSI

PART# 12-804

Image

Holley fuel pressure regulators are designed to precisely control the fuel pressure from the fuel pump to the carburetor. Too much fuel pressure for a given needle and seat assembly can overload the needle and seat and may cause flooding or drivability problems. Each Holley fuel pressure regulator is fully adjustable so regulating the fuel pressure to your engines needs is a simple task. All Holley regulators are pre-set at the factory at 2.8 PSI so there is no guesswork when first installing the regulator. The Holley 12-804 fuel pressure regulator features 3/8" NPT in/out ports.
Features:
  • Adjustable fuel regulation from 1 to 4 psi
  • .220" (7/32") restriction
  • 3/8" NPT ports ( 1 in, 2 out)
  • Chrome finish
  • Mounting bracket included
  • Pre-set at 2.8 PSI
:link: https://www.holley.com/products/fuel_sy ... rts/12-804


Listed on Amazon.com
:link: https://www.amazon.com/Holley-12-804-Fu ... +regulator

Image
Carter YH Fuel Pressure.jpg

:link: https://www.amazon.com/Identify-Rebuild ... s=bob+helt

This might also help with a more-reliable fuel control in the Carter YH...

Clark's Corvair Parts offers a replacement for the needle and seat that makes use of a ball in an all-metal assembly. It has many advantages over the standard needle and seat found in carburetor rebuild kits, as shown below...

:link: http://www.corvair.com/user-cgi/catalog ... ow_page=58
Image

Part number C3799: METAL FUEL INLET VALVE-60-69 FITS CARS & TURBOS

Weight: 0 lbs 2 oz
Catalog Pages(s): 48(10),55(12),58
Price:
1 - 3 $ 9.00
4+ $ 8.10

Image
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
AZScott
Posts: 105
Joined: Mon Aug 15, 2016 11:57 am
Location: Tucson, Arizona

Re: Fuel pressure regulator

Post by AZScott »

Thanks 66vairguy and bbodie52, appreciate the comments. My plan is to pick up a Holly 12-804 regulator.
Thanks again.
63 Monza Coupe (164-4 carb)
64 Spyder Convertable
62 MGA Roadster
74 Norton Commando
69 Triumph Bonneville
66vairguy
Posts: 4528
Joined: Tue Dec 21, 2010 3:44 pm

Re: Fuel pressure regulator

Post by 66vairguy »

A word of caution on the metal check ball fuel inlet valves. On the Corvaircenter forum some folks had problems with them on the Rochester carburetors. It's been reported some of the valves have a manufacturing defect in the form of a burr that makes them stick open.
nmunn
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Joined: Tue Sep 05, 2017 3:57 pm

Re: Fuel pressure regulator

Post by nmunn »

Regarding the Holly pressure regulator, what is the minimum input pressure required? Can’t find it anywhere in the specs.


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bbodie52
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Re: Fuel pressure regulator

Post by bbodie52 »

The Holley pressure regulator provides adjustable fuel regulation from 1 to 4 psi. It cannot boost pressure — it can only reduce fuel pressure. To adjust the pressure within the specified range, the fuel pump output would have to be 4 psi or greater.
The column of fuel in the feed line from the fuel pump deadheads at the regulator, which then holds pressure at a steady 1 to 4 psi between the regulator and the carburetor(s). In essence, a deadhead regulator is merely a restriction in the fuel line that lowers fuel pressure between the tank and the carburetor by decreasing fuel flow.
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
66vairguy
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Re: Fuel pressure regulator

Post by 66vairguy »

The stock Corvair mechanical fuel pump should operate with an output of 4-5 PSI which is adequate to make the fuel pressure regulator work in the 1-4 PSI range. Note many of the newer replacement mechantical pumps have been reported at up to 9 PSI, or out of spec.

As far as electric pumps go -- I've seen a couple that were the wrong model number with a rated output pressure that was too great.
nmunn
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Re: Fuel pressure regulator

Post by nmunn »

I’m running an electric pump with an output of 9 psi. Just confirming that is enough to open the diaphragm on the Holley regulator.


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joelsplace
Posts: 1950
Joined: Wed Oct 13, 2010 12:51 pm
Location: Northlake, TX

Re: Fuel pressure regulator

Post by joelsplace »

It should work with anything above your set pressure. If it required more pressure then it wouldn't regulate very well.
157 Corvairs, 5 Ultravans and counting
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acarlson
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Location: Dahlonega, GA

Re: Fuel pressure regulator

Post by acarlson »

According to Holley: ***The inlet pressure limitation is 7 psi.

Alec
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...
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