Toroidal Opposed Piston Engine

A 4 cylinder 8 piston engine. I have printed half of this and it functions properly (the other half is essentially identical). If you wish to print this i have designed it to be assembled with 12 mm long m2 screws and 6 bearings with an inside diameter of 8 mm outside diameter of 22 mm and a width of 7 mm (standard skateboard bearing size).

The idea of this is that it is a engine model based on toroidal shaped pistons and cylinders. The full engine is an opposed piston 2 stroke design, and if you only use half of it it would be a boxer engine design.