I just found a New York Times article which brought back fond memories. It's about people who build scale model replicas of engines as a hobby. One guy built an amazing 1/6 scale model of a Chevy V8. These really must be seen to be believed. The pistons are not much larger than a quarter. The rocker arms (the parts which help the valves open and close) are incredibly tiny. It's hard to believe these small engines actually run.
I mentioned that seeing these brought back fond memories. No, I didn't used to build working engines though I did spend many happy hours in my younger days building model cars. This reminded me of one of my favorite books of all time, Trustee from the Tool Room by Nevil Shute. Shute is my favorite author of fiction, bar none, and Trustee is an excellent example of his best work. It's the story of an engineer who builds and writes articles about miniature machines including engines. He undertakes a very long journey due to a strange twist of fate and develops some well deserved self confidence along the way. Sadly, like many of his books, it's no longer readily available in America. You can still get many, if not all, of his books from Amazon UK though.