Just my twopennorth, my primary plant genset a Perkins 4-270 driving a 37 Kva alternator is fuelled using engine/hyd/trans/gear oils blended with 5% to 20% kerosene depending on the viscosity of the incoming oil, the blend is centrifuged using a commercial clarifying centrifuge prior to use.
In September I removed the rad in order to repair the fan pulley and as the exhaust had been blowing the rad had a slight build up of crap in the fins, the rad was placed on some limestone based concrete and the crap was flushed out, anyway to cut it short the next morning looking at the crap on the concrete where I cleaned the rad I noticed that it had formed a froth and was bubbling, this would suggest that some kind of acid is being produced, sulphuric would be my guess due to the relatively high sulphur content of lube oil.
The accelerated wear on the compression rings and the upper cylinder area could be due, in conjunction with abrasive ash and higher than design combustion temps, to acid erosion, if you think about it the ingredients/conditions are all there for the production of superheated acid but not having formal chemical training its just a guess.
In my opinion, formed by a wealth of incompetence, using lube oil at high concentrations wrecks engines but with the price of gas oil ever rising there is no comparison between a few hundred pounds for a s/h engine plus a couple of days rigging it and thousands of pounds worth of gas oil. Mark,