The requirement to proof an engine is called out in the EASA/FAA regulations. (referene FAA Part 33 piston engine Block testing is one part and fleet testing is how the raise the hours. (Physical inspections on timed out engines over years of use) On the current model engines, run as specified, no issues will occur thermally with the pistons. In the case of the type 915 turbo engines, they moved that particular model to a lower compression, made with a different allow and added piston sprayers to the underside of them. This change was due to long term dyno runs (500 hour +) at the factory before it was ever released.
if you want to run the hell out of them, they don’t just explode, they die a slow death by wear and exceeding temperature/limits internally. Gear boxes could fail prematurely, crankshafts may start to twist, heads can start to crack...we can go on but I think you get the idea. the limits of operation are intended to get performance that is sustainable over long periods of time. To determine what is safe and sutable takes a long time and a lot of work.
Just one reference so you get the idea of what is required at the manufacturing level...there are many more but this is a good start.
https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_33_19-1.pdf
Cheers
