I don't see auto engines blowing a jug, or breaking a rod, or hanging a
valve at low hours, like lycosauruses.
There is no reason for all of the engine out situations that airplane
engines have, IMO.

I see way more cars at the side of the road than I hear of
airplanes having engine failures, even with making allowance for the
many times more cars than airplanes in operation. Aircraft engines fail
mostly for the following reasons:
1. Out of gas. Not an engine fault, is it?
2. Carb ice. That's a pilot's mistake, not the engine's.
3. Low oil pressure. Usually due to running out of oil, either because
it wasn't checked and topped up, or because the engine wasn't looked
after and it leaked out through the same leaks it had been leaking from
for several years, or through a blown oil hose that had been in service
for 28 years. They are 5-year items.
4. Mechanical failure. This come is a wide variety of expensive noises,
and most of them have to do with poor maintenance, or infrequent
flying, which causes corrosion internally that leads to the failure.
Mechanical failure is actually relatively rare. It's the first three
causes above that bring most airplanes down where engines are
concerned. Remember that most crashes are weather or pilot induced and
have nothing to do with the engine at all.
As far as blowing jugs or breaking rods or hanging valves: Try
making an auto conversion run at 75 power for a few hours and see what
begins to happen. They weren't designed for that, and the guys who
successfuly convert and run them for several hundred hours have had to
get around a LOT of problems.

Dan (Aircraft Maintenance Engineer, homebuilder, and Flight
instructor, with installing a Soob in GlaStar experience)