may be we can look at it from another angle. At 16.8mm stroke, assuming that the piston is traveling in constant speed (which it is not, as in each stroke there is a change of direction). At 35,000rpm, your piston is traveling at 70.6km/hr inside your engine. Add that to a serious impact, almost any crank case is going to crack.

Novarossi did put out a disclaimer in the Serpent Veteq days... where they did not design their engine to be part of the stress member in the chassis. If the impact is on the engine, it will give the same effect.