Well, I can't recommend that you use SVO or WVO, as neither is cleared for on-road use by the EPA.
Both contain glycerine, which doesn't burn cleanly much below 1000*F... it creates toxic gasses when it isn't completely burned.
The point of making bio-diesel from oil is to remove the glycerin from the oil and replace it with methanol, which lowers the viscosity of the fuel and makes it burn more like petro-diesel.
If you google "DIY BioDiesel" you'll find a load of sites devoted to it.
This is the site that I'm going with right now:
Make your own biodiesel: Journey to Forever
__________________
"¿ʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"
I'd like to think that people might open their eyes at some point... instead, I find it more and more likely that I'll just close mine.
-- Author kept secret.
Je ne veux pas d'une meilleure vie. Je veux être heureux avec celle que j'ai maintenant.
(I do not want a better life. I want to be happy with the one I have now.)