Since I bolted up a Caterpillar two micron fuel filter, I pour a gallon of waste oil in to my Duramax every other tank of fuel or so. I figure each gallon replaces that much diesel fuel that I don't have to buy. I paid for it, I figure I might as well get as much use as I can from that oil. Who knew that waste oil was worth 2.49 a gallon?
So about 1 gallon of oil to a 34 gallon fuel tank. No ill affects as of yet. The truck only has 46K miles on it though. I also run bypass filtration on it, and pull oil samples every 5K miles, just because I'm a maintanance nazi. I like less than a 5% mix. I wouldn't want to ever run more than 10 or 20% waste oil, and would definately not want to run that much all the time. Additive packeges in the oil turn to ash during combustion. As long as those levels are minimal, the ash can disperse, and that's why I don't run a higher concentration of it, or constantly. Just a single injector on a V8 Duramax is about $500. I wouldn't want to know what a compleate upper end overhaul would cost. So I don't exactly want to try too much more experimentation.
The last gallon I poured in was probably 50% waste oil, and 50% old stale gasoline. Do I Filter it? That's what the 2 micron fuel filter on the Duramax is for! Anything it misses gets caught by the stock 10 micron filter
I'm not worried aobut particles, I'm concerned with disolved metals in the additive package that turn to ash during combustion. They can't be filtered out.
I do pour it though a "filter funnel" that has probably a 40-80 micron screen. It catches sand, and chunks that would otherwise possibly clog my fuel pickup in the tank.
So, I pour it in to the fuel tank of my Duramax, but dilute it greatly. Is anyone brave enough to burn it in their Listers with no dilution at all? A Cat 2 micron filter would get it clean, and one could jerk the head off after a few hours of operation to check things over for deposits.
Worst case, a new piston, rings, injector, and valves for a lister wouldn't be all the expensive, would they?