Return Line Install Kits - Early vs Late

[jwalterus]

Remember the color of the clamps will tell you early or late kits. The smaller is the early green clamps at 3/16 and the late large at 1/4 inch is the red. Now consider the size of the fuel line feeding the filter at 3/8 inch. Then the line feeding the injection pump is 5/16. then the return to the tanks is 5/16.... So how much fuel returns in that 5/16 line... Some feel its not much. I feel its nearly 80% of the fuel sent to the engine. Remember it is fuel that cools and lubes the injection pump and the injectors. Both return kits work well and to say one is better than the other is a real stretch. We just need to remember these large and small return kits CAN"T BE used together. Every fuel fitting will have a large or small nipple especially the brass fittings on the filter or top of injection pump return.

Watchem zee video #1
you can clearly see it cycles massive amounts more of fuel through the return lines than go through the injectors
http://www.oilburners.net/forums/showthread.php?62944-TECH-101-Diesel-Purge-for-our-IDI-s

 

[BCMac]

Ok guys, next question. Is this the proper fastener to the top of the IP? Or is this what they might have ended up doing to make the larger tubing from the later kit stay tight on the brass nipple? The clips on the rest of the system are (or were at some point) red. From other pictures I am looking at, it appears that this connection is also normally one of those same clips?

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[icanfixall]

Ok guys, next question. Is this the proper fastener to the top of the IP? Or is this what they might have ended up doing to make the larger tubing from the later kit stay tight on the brass nipple? The clips on the rest of the system are (or were at some point) red. From other pictures I am looking at, it appears that this connection is also normally one of those same clips?

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This pictured fitting on top of the pump is just ONE of the deciding fitting sizes.the other is the filter bleeder on the filter housing. Many have plugged the filter bleeder and not had a way to bleed air out of new filters but all trapped air must go thru the injection pump. not a reall good idea but I did it for many years with no filter bleeder. This pictured fitting can be changed to either large barb or small barb easily. Just do not remove the check valve under it. that has to remain in the top injection pump cover. It has an o ring seal too.

 

[IDIBRONCO]

As far as what came with the truck, maybe it originally had the smaller return lines but someone put a used engine in. They could have bought the engine complete with return lines and just installed it that way. There's no difference in the way fuel gets to and leaves the engines despite return line size. Both places have a 5/16" rubber fuel line.