Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I admittedly don´t own a M92, but my M90 have not seen a single drop of oil/lubricant in the fuel, and after more than 2 cans of Zippo fuel, i have noticed absolutely no difference in running characteristics or output.
Since the engine runs quite cool and wet from fuel on its own, and the pistonrings are made of rubber/nitrile, little to no wear is expected in the cylinder.
Personally i prefer this to avoid any chance of gum forming during longer storage, over the slight inconvenience of having to change a very cheap rubber-ring...which by the way will decay and stiffen up over time on its own anyway, nomatter if its greased up by the fuel or not.