Hello All
I'm very close to finalizing the fitment of the 3304DI 83Z0704 engine into my 955K chassis and one of the last things I need advise on is the fuel supply lines. The 955K with the D330 and the 955L with the D330 and 3304's all have one fuel line from the fuel tank. The 3304DI engine has both a fuel supply line and a return line back to tank.The tank does have two outlets on the bottom. One for supply and one for drainage. Do I need to run a second pipe to the tank or is there another option such as a valve in the supply from the tank? The 3304DI has the scroll injection pump with a piston type transfer pump. The engine did not come with a priming pump although according to the parts manual for the engine it should have one.
To confuse matters more my 944 with the D330 engine has both a fuel supply and return line to tank.

Regards

Phil

Seems some have a return line and some don't. The industrial engines seem more inclined to have one. In  any event if there is a return line be sure there is a restriction orifice in the return circuit to minimize return flow.

Hello OM
Thanks for your reply and many thanks for always helping out with these issues.
I found this thread from 13 years ago where bob says the return line is for engines that have the fuel tank below the pump to provide constant bleeding which makes sense as the 944's tank is below the pump.

I wonder if you could just plug the return line. Do you think Cat would be able to help out with some info on this?

On another note do you think I should fit a primer pump to this engine? I started it a few years ago and it had no problem picking up fuel from a container on the ground and that would be more difficult than getting fuel from a gravity feed tank.

I don't see any issue with plugging the return line. If you wind up with priming or air locks you could always go back to a bleed line.
Same with the priming pump. Not all units have that feature. They are nice to have after opening the system but not necessary. They also can create problems due to lack of use.

Thanks OM
I wasn't sure if plugging it would cause issues.