I've been burning WVO for about 5 years now. Two cars blending and one with a Greasecar kit and a FPHE.
Rosenfe is right on with the research bit. There is A LOT to learn about this.
One mistake I made early on was mixing in some used motor oil. That wasn't the problem though. What created the problem was adding Diesel Kleen additive. This made the motor oil precipitate out of the mix and collect on the bottom of my tank in a tarry like substance. What a mess that was.
Best advice is read, read, read. If you like PM me and I'll send you several sites for WVO where you can do your research.

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Muleears
'07 E320 Bluetec 133K my DD
'04 Jaguar XJ8 VDP, 34K
'10 Hyundai Accent 60K Grocery Getter
'02 VW Golf soon to be on the road again
'97 E300 Diesel Son's DD
'61 VERY tolerant wife

Hampton Roads, VA USA

Gone but not forgotten:
'67 250S 95K
'86 300SDL
'87 300D Turbo, 364K! R.I.P.
'98 E300 Turbodiesel, 213K
'02 S420, 164K
'01 Prius 138K