From left to right:
Standard Lego Technic Cylinder engine vs compact Lego Technic straight inline 4 cylinder engine Mark 1 by Siddhart Jaipal.
Instead of building around the standard Lego Technic cylinder engine, I created a smaller mk1 inline four cylinder engine. The L-shaped gray parts hold the rubber bands and the upper layer of the engine together. The Mark 1 engine rotates well, but it feels sturdy as a result of too stressed rubber bands.
Uploaded: May 4, 2016