Hey guys,

The block I have has no hole for the fuel pump pushrod plus the cam has no extra lobe.

So I'm about to set up my electric pump. It's rated at 7.5 psi & 100 GPH. I was wondering if, since the mechanical fuel pump (which I have mounted on the block right now) is internally regulated and has all the provisions for the return line and output for the carb hard line, would it be suitable as a fuel pressure regulator? Or will it not regulate properly because the pump isn't being actuated by the pushrod?

Thanks

 

Neither a mechanical or electric pump are designed to reguate. Its a nice thought but the mechanical only has a diaphram to pump fuel - no regulation of any kind.

 

Been using mine like that for several years.

https://www.thirdgen.org/forums/carb...regulator.html

I've since gotten rid of the baby fuel regulator shown in the post, along with the plastic fuel filter (which I just used so I could verify the flow). Car's gotten several tens of thousands of miles since 2007.

...I've also, of course, routed all of my electric cables correctly-the photo was taken before I cleaned everything back up after re-installing the metal fuel lines.

 

A mechanical fuel pump regulates itself, true, but can't regulate fuel being forced through it. If you were to apply fuel pressure to it you would find that at around 1 PSI the series of one-way valves inside it would unseat and fuel would flow through it unobstructed above that pressure.

Get a real regulator and use it.

I also don't like using low pressure electric "helper" pumps as the only pump in the system. They have a hard time holding 6 PSI at the carb pushing only 7 PSI from way back at the tank. The force of acceleration acting on the fuel in the lines is more than it can work against and you'll often find fuel pressure dropping off pretty dramatically up by the carb when you nail it in the lower gears.

That's why you start with a pump that can feed more than the engine needs and then regulate it down to the needed pressure just before going into the carb.

 

Depends if you're talking about a pump with a return line or not.

 

It has a brand new Mechanical Pump with a return line.