Miniature engine. It doesn't need anything but printed parts, assembled as is. Engine is rotating sample.

Filament needed ~46gr.

Assembly

1. Put pistonpin in piston hole a bit
2. Take piston rod and in piston, then press piston pin trough piston.
3. Piston rods goes around Crankshaft, piston with rod on shaft, then little pistonrod piece is snapped on place
4. Put crankshaft and piston set to block and last put crankbearings in place. Those goes only oneway to their places.

This is first version, i might update it later. I have alternator, waterpump and so on in my mind.