Originally Posted by
elmshoot
I have seen too much oil kill an engine, ring failure in that case. Personal experience but not in a model application.
Miss calibrated dip stick, the company wouldn't stand behind their error.
I agree oil is cheap, engine failures are expensive not to mention the potential for the crash landing.....
Sparky
Yes, you are right, I should have specified "mixture-lubricated".
If the discussion is about sump-lubricated engines, then sure, overfilling WILL kill an engine, and in lots of different possible ways. I have seen an engine lose oil pressure due to overfilling, fortunately the engine was safeguarded (autostop) or it would have destructed itself.
Overfilling can kill rings as you say, it can blow out shaftseals (not really engine damage, but a nasty overhaul nonetheless on a diesel larger than a decent-sized pickup truck). It can kill bearings in the valvetrain or even the intermediate gear breaking free of its brackets (Hydraulic forces of the oil enclosed between the gearteeth overloading the bearings), it can cause mainbearing faillure due to air in the oil (crankshaft whipping up the oil to a froth), and I am sure there are a few other ways I forgot.
Nowadays I work with what basically are just glorified truck engines (up to about 500 hp), Those come with factory calibrated dipsticks. But in the earlier days on the transatlantic trade, those engines came with unmarked dipsticks because the actual marks depended on how the engine was installed. We were told to, after installation (newbuilding), dump an X amount of oil in it, then mark the stick for that level as "min", add another Y amount of oil and mark that level as "max"...
But this is mixture lubricated engines, and there is is harder to kill an engine. Only two ways I know of is either a conrod with needlebearings giving in, or the engine getting overcompressed from the oil volume in the combustion chamber. Those needle bearings are rather sensitive, overcompressing it takes a huge crapload of oil in the fuel.