Yeah, the torsion on the flat conrod must be a problem, for sure. But, in theory, there is very little piston slap (if that means the side to side force that the skirts resist), and the valve train is completely standard. They have more or less equaled the Atkinson efficiency of the Prius -- which is the best for any gasoline ICE, is it not?
I wonder what would happen with the Revetec as an Atkinson / Miller cycle? Or, if rotary ball valves could work?
Have you seen the
Garric rotary design?