How healthy is it to run substitutes of fuel like used motor oil, ATF, kerosine, etc. in the 12 valves? To a ratio, not straight.

 

Filter it REALLY GOOD and you can do half tank oil, half tank diesel. It really helps lube the pump.

 

Kerosene (straight) = Bad - no lubricity
WMO (Waste Motor Oil) = Okay 5% - 75% mixed with diesel, depending on who you believe.
Lots of lubricity, more smoke (white/blue)
Kero + WMO = Okay


I run 20 - 30% WMO + diesel. I get a little white/blue hazing at idle when the engine is cold which clears up as the EGT's go up above 400. Some guys run up to 75%. That's probably okay in warm weather, but I'd be afraid of it putting extra strain on the lift pump, filters and injector pump because of the viscosity when its colder out.

The WMO requires either pre-filtration down to 2 - 5 microns or so to remove the carbon and any metal particles, or finer filtration between the tank and injector pump. I have 3 filters in line, 10 micron (stock filter), 5 micron and 2 micron, piston pump, pressure gauges before and after filters. With this setup, I just strain it to remove any chunks and dump it in the tank. I'm going to be setting up a 50 gallon in-bed tank for WMO/Diesel mix and keep the main tank straight diesel. That way, I can start up on plain diesel and not smoke out my neighborhood in the morning and switch over to WMO blend once the engine has warmed up a little.