It takes a lot of skill to make one of these, but for an observer unfamiliar with some of the minutia that goes into making a gasoline engine it’s probably no more impressive looking than a miniature steam engine or stirling engine, both of which are much easier to build and can run off of a variety of fuels other than dinosaur juice.
I built an ice-cube powered stirling engine in college and later a little steam engine as a quick hobby project. I’ve been thinking about trying someday to make one of those low-temperature-differential stirling engines that can run off of the body heat from your hand. It’s less complicated than a gasoline engine but probably a better conversion piece. Certainly quieter and less stinky.
