Toroidal Piston Engine and 2 Speed Gearbox

A 2 cylinder engine attached to a 2 speed transmission. I have not printed this, however I have printed an engine model based on a similar design that functions properly. If you wish to print this i have designed it to be assembled with 12 and 8 mm long m2 screws, 2 2 mm diameter metal rods at 53 mm in length and one at 4 mm in length, and 7 bearings with an inside diameter of 8 mm outside diameter of 22 mm and a width of 7 mm (standard skateboard bearing size). I plan on having this printed and will fix any parts that don't work correctly.