i would say go biodiesel. its not hard to make, and you can eisily get oil from your local fast food joint. you would also need lye and some ethanol/methanol. mix it w/diesel some depending how much you make, if you want to run it in the engine you have w/no modifications i would say mix it around 50/50 cause pure biodiesel will eat rubber and lose some power, but i dont think its a huge loss, if it cost less you can save up to modify that french fry cooker!