If I wanted to figure out what’s breaking a particular kind of piston aero engine (other than purely random failures), I’d set one up so that I could be sure that all cylinders are operating between about 40 and 50 degrees rich of peak on the lean curve, at high power and a relatively low cruise RPM.
That way I’d be giving the engine the toughest pounding that I could possibly give it. (Ssshhhhhh: Don’t tell yr right, but that’s ROP….)
I’d then apply time and observation.