Fuel Supply

[enforcer]

I am using a standard Pinto 2.0L with carbs. As far as fuel supply goes I am intending to use the Sierra's set up incorporating the three way thingy between the mechanical fuel pump and the carb, and having a return pipe to the tank.

 

Is this necessary or has anyone successfully run a single fuel pipe direct from pump to carb without a return or using the thingy?

 

Without using a return would free up one of the pipes from the sender unit to act as a vent, but if I end up with a return I presume there is a need to add an additional vent pipe to the RH tank (which incidentally looks like a pig to fit to the chassis)

 

Your observations Gentlemen please!

[ibrooks]

You need a single pipe from the tank to the pump. From the pump you go to a pressure regulator. This sends one pipe to the carb and another back to the tank. The fuel being sent back to the tank is the excess that the pump shifts as it is capable of moving more than the engine needs. The reason that the Sierra setup has it going back to the tank is that the "three way thingy" is also a vapour separator and so there may be gas in that line.

 

If you ditch the Sierra regulator and get a filter king one it is a diaphragm type and just closes off when the pressure is too high so you don't need a return line. It's also available with a built in filter which sorts that job at the same time and it's adjustable. Vapour separation isn't necessary with shorter straight lines as any bubbles that form are relatively quickly forced through the system and cause no problems. In the Sierra where the pipes run up and down there are areas where bubbles can collect and then all come through at once and possibly cause the engine to stutter.

 

If you are determined to use the Sierra regulator run the pipe with a rise at each end and flat in between and just T the return into the line that supplies the pump at the front of the car.

 

Iain

[Longboarder]

I run twin forties on a single line from the tank to the sierra mechanical pump then an inline cheapo filter to the carbs. Not had any problems. Don't think the pump produces enough pressure to regulate but it flows enough volume for 120 bhp at the wheels.

 

Nigel

[Guest daveg]

My 2p

 

If uncle Henry's design engineer fitted something, I assume it was for a good reason, therefore, I fit said item too

 

Dave

[Guest Charles B]

I use a single feed through a filter/pressure regulator and standard mech. fuel pump to a pair of dellortos, and have no problems at all.

The only reason I can see for putting in the return pipe is if you ever intend to fit fuel injection in the future.

[Guest Charles B]

I forgot to say, I don't have a vent pipe with the R.H. tank. I think there must be enough bleed through the filler cap, as I have had no problems.

[Guest Battery Bill]

Daveq

uncle Henry's design engineer fitted something, I assume it was for a good reason

Unlike you to follow good reasoning!

Charles

I love your signature

Made me chuckle it did