1994 Ram 2500 4x4 auto.
I'm ready to convert this old heap to run on veg oil. I haven't worked out what to do about the return line that goes from the injectors to the diesel filter. I can't leave it hooked up the way it is. It has to be switchable so I can return it to the alternate filter (or tank) when running vegetable oil. Can't have WVO going into the diesel filter.
In order to avoid cutting the line, I'd like to be able to just disconnect banjo fitting from the filter and attach another piece of line to it. Can you connect two banjo fittings end to end?

 

if the WVO is hot enough it should pass through the diesel filter.

you are planning on heating the WVO?

otherwise yes you need to transfer the source and return lines to the respective tanks

don't know about the banjo fittings

-dkenny

ps or you can learn to make biodiesel and skip the problems converting the truck

 

I said, can't have wvo in the diesel filter. Can't mix them. It's not okay to have wvo going into the diesel filter.
Need some kind of adapter for the banjo end of the injector return line.

 

A pollak valve has return line switching that will solve your issue. They are used on many Ford duel tank applications in the 80's and 90's. It is a favorite for wvo installers. They are usually installed on the frame between the tank and the engine. I have never seen any bad effects of running wvo through the diesel filter unless you run in very cold climate or don't switch back to diesel a few minutes before shutting down. The idea is to only use wvo when it is warm. Start and shutdown on diesel. If temps are over 80F in your area you don't have to purge the wvo.

BTW the pollak valve also has a built in switch that will switch your fuel sending unit to the other tank as well.

 

Check out my photos for some schematics if you want. Theres also a lot of info on the frybrid.com forums.
I bought a pair of hydroforce 3 port solenoid valves that supposedly can take the heat a bit better than the pollaks. I still have 2 new pollaks I should probably sell off.
You switch the feed and return lines between the two tanks. When you go back to diesel you keep the return on veg for a couple minutes to purge.
For the frybrid setup I think you cut the injector return line that hangs down at the end of the intake plenum and use a hose to route it to T into the return line from the pump.
Id strongly recommend a heated pickup, filter, hose in hose lines and a heat exchanger up in the engine bay. There are also nichrome heaters you can use on your injection lines if you want.
Some folks loop the return back to the feed on veg so the heat is maximized, but it makes bleeding the air more difficult.
You can get glass sight tubes from mcmaster-carr. They seem to hold up to vacuum as well as pressure. Makes it easier to chase down air leaks.
I would also be sure to read the laws in your state regarding road fuel tax. You dont want to get hit with a fine for that, its huge. This is part of the reason I dont run mine anymore, the red tape is ridiculous.