The scale stuff always intrigues me, check out these guys ; http://www.conleyprecision.com/
not as complicated as the scale napier deltec but cool still. I really like the short clip of the Cobra.
Here's a link to a good friend of mine's web page . He brought a 4 cylinder 4 cycle engine with him the last time he came here to visit. It ran on alcohol, and the only byproduct was water. It was a very smooth running and quiet engine. Jerry is the most amazing machinist I have ever seen. He takes perfection to the next level in all of his hobbies.