Nico71 - Lego Switchless Pneumatic engine mk2. With stacked 4 valves instead of side by side, one cylinder and two speeds gearbox. Expected to me mounted soon in a two wheels creation
Watch as the Guys From Lego Pneumatic Engines Build a Working V8 Out of Legos
LEGO MOC 1 Cylinder Lego Pneumatic Engine - Modified (High RPM) by Green Gecko | Rebrickable - Build with LEGO
These Air-Powered Lego Piston Engines Are Hypnotizing To Watch