Typhoon:
I'd just like to point out that auto engines are not near as frail as many here are pointing out.
Many, many manufacturers randomly pull an engine out of production and subject it to extensive, punishing dyno work. Even in the 60's, Chrysler would run production V8's at max rpm/load on dynos to the point of failure or 1000 hours often easily going well over 1000 hours with no failure.
Let's not even start on plain old auto engines which are converted for marine use which run at a constant load and power setting for hours on end.
Certified aircraft engines are great things, they are light, simple and reliable, but they are not even close to being optimised for what they do. They are old designs optimised for what they have to do, but no way are they an example of the perfect solution for the job.
The only reason they are still what they are is certification costs and lack of manufacturing volume to justify new designs.
This is bull****.
1. You still don't understand
duty cycle. It is not "running 1000 hours at full throttle".
For an aircraft engine it is:
(a) cold soak on wet aerodrome for one to three weeks.
(b) start engine, warm for ten minutes or less.
(c) Apply full throttle for Five minutes. Then cruise power.
(d) Repeat this cycle of thermal loading for at least Five years, with periods of abuse like subzero starting, high temperatures etc. thrown in.
2. New designs
offer no benefit. Because of the limited operating rev range of the propeller and consequentely the engine. All of the new technology stuff in auto engines is to improve fuel economy through reducing volumetric losses or to improve the shape of the power curve by widening the band where efficient combustion is available..
If an aircraft engine was required to have a power band from say 1500 rpm to 5000 rpm you would be right, but it doesn't.
3. The marine variants of automotive engines are derated by between 50% to 66% of their advertised "automotive horsepower, except for the "consumer" outboards whose duty cycle is similar to a car anyway.
Jabawocky you are confused about power curves. It is possible to seriousy bugger an engine. The performance is optimised as a torque/rpm combination
The curves you see are actually advertised torque at maximum power for the specified rpm.
To put that another way, you can strangle the engine, it will run over torqued,, but at less power.