never accomplished the goals in the previous post....but i did do a new veggie oil system in my current bus..it's not quite finished though.
I believe that the 2 heated veggie tank system is the way to go. Pump "dirty" oil in to the first tank, heat it, then filter it into the clean tank.
I tried running my new bus without a return line when i went to nevada and back. I could not get all the air out of the line. I finally switched back to using the return line, and i'm much happier with the way the bus runs.
Having electric fuel pumps in the veggie and diesel fuel lines is also a really great idea. They don't run constantly, but are used just for priming the system.
The pollock 6 port valve costs about as much as 4 brass manual quarter turn valves. if you're gonna do veggie, buy the 6 port electric valve!
I thought i made a post about it sometime ago in the past...but can't find it. My current bus has some good lengths of heated fuel line that look like this.
This particular photo is stolen from somewhere on the web...I did however reverse the coolant and veggie lines in my setup. It made more sence to me to have the coolant in the big tube, and the veggie fuel line running through the center.
One more thing i changed in the new system: larger fuel and return lines. I used 1/4" copper tubing in the first bus. This created much higher pressures in the return line than were necessary, also made the system impossible to run without an aux pump. I think that 1/2" tubing/hose works much better, and is way safter for the injector pump. In the current bus, I used a combination between copper pipe, and flexible clear tubing. The biggest disadvantage of the tubing is that you cannot use a torch to heat it up if the veggie coagulates in the line.