Complete hardware kits that include all the non-printed parts can be found over at MakerRx
Complete hardware kits
Completely reverse engineered Toyota 22RE 4 cylinder engine. Can completely print a fully rotating model. Working crank, pistons, and valve train. The valves open and close!!!. It may not be the most exciting engine but its the only one I had in my garage. Great if you want to learn about engines and how the moving parts in them work. All parts are printed except for a few bearings and fasteners.
Update 09/01/2020
Entire model has been redesigned to allow for easier assembly and better part fitment. New model has working LED spark plugs and a cut away block where you can see the rotating crankshaft without removing the head.
This model was reverse engineered from a 22RE Toyota engine, All modeling was done in SolidWorks and the STL files were scaled to 35% for printing since that the biggest my printer could print. All parts were printed in PLA on my RepRap original Prusa. There are 80 printed parts in this assembly, not including any fasteners or bearings. Probably a whole 1kg roll of plastic.
See pdf for complete printing and assembly instructions.