Point taken that explanations are more important than descriptions but really there are thousands of places that explain the principles of how the internal combustion engine works.

This is the first time I've seen an engine physically taken apart so I can see roughly what goes where. I'm reminded of 'Danny The Champion of the World' who, at the age of seven, could take a small engine to pieces, and put it back together again. Pistons, crankshaft and all.