Housing: External casing based on 13B-REW block from 93-02 RX-7.Exhaust holes on the side have different outer and inner ports.

Rotor: Round recess balls near the corners on top and bottom surface.The outer arches to more accurately resemblance of the engine rotors.

E-Shaft: extended the hex section to stack more layers of rotor housings and eccentric wheels.

Housing Rod: Print 2x to stabilize the housings when stacked together.

Shortened the finger loop connector of the e-shaft(crank) so this model can still be spun while sitting on the table.