Isn't there a theorem stating that circles (not ovals) have the most surface area when given a certain amount of material, or most efficient use. Besides, circular pistons distrubute power evenly, it would be hard to balance oval pistons IMO. I think they were only used in motorcycle applications because there was only 1 (maybe 2?) pistons. I haven't heard of that though (I've been involved in motorcross racing) and I'm sure if they were extremly beneficial they would have been used in other cars, or at least high budgeted race teams were performance usually out-weighs functionialty (that a word?) and reliability. But very interesting idea and I would like to hear more about this crankless motor and turbine injection...I like this engineering shizznit, hopefully go to school for it and be designing your Nissans in 10 years.510Mods said:With round pistons, there is no extra force for the air to be sucked/forced into the motor, besides turbo/supercharging. With an oval piston, the force of the crank will use a larger surface area to seal the chamber. The pistons are more efficient to draw the air/fuel mix into the motor, like a straw. Thats all a motor is right, an air compressor with an internal power source??? The motor would be longer but skinny, so it could fit a datsun 300z with ease. What till you hear about my crankless motor and turbine injection. By the way, oval pistons were actually used in racing motorcycle engines.