If it is OIL, and if the viscosity is about right, the engine will run fine, veg or mineral, it doesn't matter. Don't worry about lube oil dilution either as veg oils are better lubes than mineral oils, and anyway, the amount veg going down is tiny.
Our best ever brew (aka ROCKET FUEL because of the effect) is lube oil from a big machine, thinned with kero till it sloshes around about the same as diesel.
Discomania's NA Def 90 really shifts running on this stuff, and I did a 450 mile round trip in the Disco TD5 towing a caravan using it. Uphills on the M74 and M6 was superb using this fuel - far better pulling-power.
If I knew of any way to filter old engine oil well enough I would use that for fuel too. There is NO reason why not.
CharlesY
Our best ever brew (aka ROCKET FUEL because of the effect) is lube oil from a big machine, thinned with kero till it sloshes around about the same as diesel.
Discomania's NA Def 90 really shifts running on this stuff, and I did a 450 mile round trip in the Disco TD5 towing a caravan using it. Uphills on the M74 and M6 was superb using this fuel - far better pulling-power.
If I knew of any way to filter old engine oil well enough I would use that for fuel too. There is NO reason why not.
CharlesY