Thread: V8 fuel return hose?

Slunnie,
It's a return line, just run a hose back to the tank.

My Stage 1 has the same setup and the return line does go to the fuel tank and yes I would think that it needs some restriction to maintain fuel pressure at the carbies mine just has a thinner hose on the return line.
My earlier Range Rover had the same design carbies and the same fuel pump and used no return line so I am assuming that you could terminate at the return line, I havent blocked off the return line because I think it helps with vaporisation in hot climates but that could just be an unproven theory.
The return line is a right PITA if you have dual fuel tanks as the return will overfill the main tank if you are not careful.

As above but the carbys are designed to run on low pessure 2PSI , AFAIR.
The different sized hoses provide this restriction when a Facet pump is used. So maybe a single hose with a pressure regulator will work, but I agree that this may cause vapour lock.
AFAIK this so the carbys do not flood on rough roads. ie high pressure does not squirt copious fuel through the needle and seats if they bounce.
Regards Philip A

Ahhh, very interesting. Thanks for this fellas. I'll try to T it back into the sill tank breather so that the fuel can keep circulating then.

Originally Posted by Slunnie

Ahhh, very interesting. Thanks for this fellas. I'll try to T it back into the sill tank breather so that the fuel can keep circulating then.

I always thought it was only to eliminate vaporisation. Maybe its dual purpose ?? - I would then only have been half wrong

The use of a return line may also have been due to the design of the Lucas fuel pump which apparently relies on circulating fuel for cooling - the return line allows fuel to flow through the pump continuously.

When I converted to LPG I had to install a cut off solenoid in the return line as well as the delivery line as the SU carbs were sucking fuel from the tank via the return line when the delivery line was closed for LPG operation. This resulted in the engine trying to run very very rich on both LPG and a dribble of petrol. There was certainly some frustration experienced before I realised what was going on!

On some V8 site - I think it's the rpi one - they mention using a MIG tip inside a return hose as a restriction. Apparently the 0.9mm hole in the tip does the job, though I'm going to stick with the Rangie hoses when I do the same conversion on my SIIA.

I've already got one of those big Lucas diesel filters on it, (though it's a petrol), and the instructions say that there's a fitting at the top of the filter housing that can be used for a fuel return.

These filter assemblies are very common and you may want to use one because you not only get somewhere for a return but the best filtration possible as well. You may have seen them around - they are the ones with an ally casting on top, a disposable cylindrical filter, a glass bowl, and an ally bottom part.

Ah, ok. It sounds like its possible to reroute the fuel back into the fuel lines then rather than the tank, although not the most ideal situation.

Are there any issues with rerouting the return line into the tank breather rather than creating a new hole into the fuel tanks.