I am going to replace the fuel lines in both my diesels. I will be using WVO. Orings are viton but what material is best for fuel lines? polyethelene, PTFE, FEP or what? I would like to buy the line bulk at McMaster and Carr or some other place but need to know the material.

Unless you plan to run biodiesel, standard rubber fuel hose is fine. You can even get away with running up to B20 (20% bioD, 80% D2) without any problem.

Edit: After reading the original post again, I agree with the post below. Rubber is not "the best" in the long term. However, crawling under the car to run a new rubber line in three years doesn't worry me in the least bit. I guarantee you though that I'll be using that mcmaster PVC stuff next time! $1/foot is a bargain compared to viton (~$6/foot last I saw).

WVO and biodiesel are very harsh on rubber, and many other materials. Use viton, or SAE30r9 spec lines and only replace once. More expensive, but I prefer to get under the car as little as possible. This spec will also hold up to higher temps in case you use fuel heaters at some time in the future. Standard lines will be destroyed in just a few years using non-diesel fuels. While you are replacing the lines, consider new stainless steel, rolled edge hose clamps.

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Mercury is a boxer

1984 300d
1999 Prelude
Medici road bike
Klein touring bike
Klein mtn bike

I've heard good things about this, but no first hand experience.

http://www.frybrid.com/forum/showthread.php?t=7692

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Pictures of the MB: http://s230.photobucket.com/albums/ee41/EricandRobyn/1981%20Mercedes/

1981 300 SD with a Goldenrod water block and Injetor line heaters. EGR is missing

1999 F-350 with HP X-over, Dahl 100 Fuel Filter, Coolant by-pass filter, CCV mod, Tymar intake.

Both on single tank WVO blend

I love look of that clear mmc p/n 5549K48 ! So easy to see whats happenning. I wonder how durable though...

I used the braided mmc p/n 5439K21 and its plenty strong so far (5k miles).

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Paul
Benz-less
I need an SDL !