In the past as a courier, my van clocked up over 500,000Km in the first 5 years.. and the other rodeo ute, had 680,000 before we removed the heads for a look, both engines, Petrol, still had the hone marks on the bores.
If the oil is clean, and the engine kept cool, then 1,000,000 is no drama for a modern engine.. 1.5Million Km is considered Low miles for some truck engines.
High revs, and lean of peak mixtures, and the engine will run clean, be under less stress, (true if you have seen an aircraft run on a modern dyno), and have no reason not to go to TBO.
what will kill an engine within minutes if not seconds, is Pre ignition. detonation isnt too bad, still not good, but light detonation will not harm an engine in the short term. heavy will. running in the red zone just rich of peak, creates the most stress on an engine. that stress being internal cylinder pressures, running lean of peak, and higher Rpm, and full throttle will see pressures around 600psi. just rich of peak will have them up around750 to 800. detonation, just a little higher, but pre ignition will get them well over 1500+ psi, and into destruction territory.
best to be full rich, or lean of peak. anywhere in between will increase wear through higher internal pressures.
i would really love to see a jabiru engine put onto a proper modern dyno with real time monitoring of internal cylinder pressures, timing, mixture, CHT and EGT's. a lot of issues can be resolved with that kind of data! after seeing a lycoming engine on a dyno with the parameters above, its easy to see just how a bad mixture, bad plug design, plug damage can cause the stresses that result in the kind of failures that show up all to often with jabiru engines.
i hope the modifications and changes by Camit are a result of such research, if it is, then they will have a winner of an engine on their hands!
also noted on the dyno run and data i saw, Lean mixtures had nothing to do with detonation. or burnt valves... flame suite on..