Based off of http://www.thingiverse.com/thing:1176934.
A wobbler type compressed air engine with main bearings and a display base. When running (see video) achieved a speed of over 3300 RPM.
Bearings are 608ZZ. Spring is 3/8 x 3/4 compression. All bolts are M3.
Included is a .step file of the assembly if you would like to make your own modifications. Also a picture of how I printed some of the support parts.
Moving parts and hose barb were printed with 100% infill. All others 30%