The Stovebolt Site Forums The Shop Area Engine Shop Anyone running a fuel pressure regulator᠁.

…on a carbureted 235?

And if so, any experiences positive or negative? Or recommendations on what type to use or not to use?

Seems to me this might be something more and more of us will have to consider. Your odds of getting a new pump that runs in the proper pressure range nowadays are probably slim.

I have no direct experience with regulators on a carb’d engine. As I understand it, there are both deadhead and bypass types, with some advantages to each. It’s a little tough for me to imagine a bypass type with the in-cab-gravity-fed tank for an an AD truck. I suppose it could be done if one was determined to do so.

I'm looking for the same thing.
1953 GMC 228
new mechanical pump not working, flat cam lobe???
installed electric pump and it's overwhelming my float/needle.
thoughts???

I'm running one of the cheapest ones from amazon... set at around 4-5 psi. Same reason as you. I also though on an inline pressure gauge to see what it was doing.

Every parts store carries fuel pressure regulators. Most are adjustable by turning a knob. Get one in the desired pressure range and install between fuel pump and carburetor. Couple of rubber hoses and 2 clamps and you’re done.

If you want to have a pressure regulator which has a return going back to the tank, you can install a '54-'59 sending unit which draws fuel from the top of the tank (instead of from the bottom of the tank). I prefer the '54-59' sending unit because it has a sock on the end of the fuel pickup tube as opposed to the original bottom fuel feed setup which is easily clogged with debris settling in the bottom of the tank.
You can then use the fuel bung at the bottom of the tank for your return line.

Is that the setup you run?

The electric pump I've used for over 20 years is engineered to provide about 3.5 psi...which is more than you'll need for a carbureted 235 with a single bbl carburetor. Once pressure reaches about 3 to 3.5 psi or the carburetor fills up and the float shuts off flow, you can hear it sort of idling...maybe like it stops trying to pump anymore. I think the max pressure was 4 or 4.5 psi and I want to say the minimum pressure was 2.5 psi. I paid less than $30 for it. Autobest is the brand name and as I understand they moved mfg operations to the USA sometime in the 2000s. I can check but I think the part number was F4027. Great fuel pump. No worries. I replaced the first one because it was over 20 years old. It was still working, though. Seemed like a good investment for the future. Makes starting the truck a lot quicker.

Oh, also I should point out any electric fuel pump was engineered to push fuel from the tank to the engine...not to suck it from the tank to the engine. So the closer you mount it to the tank the better it will work.

And I've found that those small cheapy electric pumps need to have gravity flow, so just like the location of the engine mounted mechanical pumps they need to be below the fuel tank. Like Jon says they don't like to suck the fuel.

If you're using the mechanical pump you could run the return line back to supply just before the fuel pump, it would then recirculate fuel from the regulator and use only what is needed at the carb.

I use a '54-'59 sending unit without, but do not use a pressure regulator since my stock glass top mechanical pump works fine.
I never have to worry about random debris shifting around in the tank and intermittently plugging the 1/4" hole in the bottom of the tank anymore.

Try a carter P4070. 4-6 psi internally regulated. Was originally designed for the military. Install near tank, put a fuel filter before the pump. This pump uses the fuel to cool the pump so you have to keep the junk out or it will jam up. I have run them for well over 40 years. Decent option.

There are a couple of options for a low pressure regulator. One of the more reasonable I this one fron Holley,


https://www.holley.com/products/fue...rs/carbureted_regulators/parts/30-804QFT

Why two outlets on the regulator?

Did you run hard line through the cab floor? I’m not familiar with the task force setup.

Yes. The line runs in front of the tank along the driver side tank strap. The tank is recessed there, providing room for the line to head down where a hole was drilled in the floor. I used a grommet in the floor to protect the line.

235's were used on TF tanks and mechanical fuel pumps. NO regulators. NO return lines. Carl has confirmed this.

I have an electric fuel pump on my 235 1bbl. It's a Carter pump rated at 4psi.
The carburetor, I understand, likes 2psi.
I use a cheapo dial regulator in line just before the carburetor.
After reading that flow tests consistently rate the regulator at double the setting, I've set it at 1psi and 1.5psi. My 235 runs well either setting. But without further testing, I like how it runs at 1.5psi a little better.

I have used a number of regulators over the years and all of them worked as they should. The Mr Gasket dial regulator most auto parts stores sell work OK and are easy to use. The numbers may not be what the pressure is, just as Don found out in the above reply, but the ease of adjustments lets you test pressures while out running around. Once you find what the engine likes, leave it and forget it, don't worry about what the actual pressure is. Same could be said for any regulator, but most all the others require tools and a gauge to adjust.

I run Malpassi "Filter King" regulators on everything since over 30 years now, they are really nice and period looking.
They come with or without filter, some even come with a pressure gauge.

Frank

That filter king unit is really sharp looking. More period
-correct look than about any other regulator I’ve seen.

Nice tip. It’s pretty spendy here in the states, however.

I bought one last spring from Mecatechnic, a parts store in France. It cost just a hair over $100 shipped to Texas, and arrived in a couple of weeks. I got this one because I didn't want to mess with rubber hose on the barbs, and preferred the fittings for hard lines. All the ones I could find stateside had the hose barbs and cost a bit more. The best price I saw stateside was from a VW parts place in California.
https://www.mecatechnic.com/en-GB/f...technic_en&queryString=filter%20king

I ran it briefly with a YF, and had it located where the factory horn mounts on a 216. I don't think it liked the exhaust heat, and the YF ran rich due to the needle and seat issue discussed elsewhere on the forum here, so I took the YF and Filter King off. I intend to mount it on the passenger inner fender, just need to find time to bend some line and fab a bracket.

Frank (Stovebold6), I'm curious to see where you have yours mounted.

How is the desired fuel pressure obtained with the Filter King? Is there a dial or something to set it at the pressure you want?

The exploded view was too blurry to tell.

EBS,

How big is the thing? Can it just hang off the carb like one of the Ac glass bowl filters?

I’ll answer my own question. Found some pics and videos. It’s large. Definitely too large to just hang off the carb like an old glass bowl filter. The commonly available one is the 85mm model. There’s a 67mm, which is suspect is also too big and doesn’t seem to be available with threaded type inlet/outlet.

Take off the acorn nut, loosen the lock nut, turn the screw to adjust (1/2 turn at a time, according to the instructions), tighten the lock nut, replace the acorn nut. There's a port to mount a pressure gauge.

https://www.dellorto.co.uk/wp-content/uploads/2015/05/Filter-King-Instructions.pdf

I don't have a picture, but it's at the firewall - a bit higher than the carb, close to the hood hinge.
My fuel line comes from inside of the cab, not around the front of the engine as usual.

And yeah, they got expensive over here too. When I bought the first one - about 30 years ago - it was 25 bucks.

Frank