Building a Model Engine of some sort....

Been looking around on the internet and see lots of people making small steam/air powered engines. Now I want to make an engine too... but maybe something a bit more useful and modular, something that I could convert into a gasoline engine (likely supercharged) or use as a high pressure air compressor if I wanted to.

So spent a few hours in autocad and came up with a hopefully easy to make first half of a conventional engine.

This engine has a 1.5in(38mm) bore and 1.5in(38mm) stroke. The most complicated thing to make here would be the cooling jacket which I wont even attempt until I convert my mill to CNC. Everything else is flat rectangles or circles, and using split copper tubing as sleeve bearings.

Finishing this as a high pressure multistage air compressor would be the easiest way to go as I will just need to use check valves between the cylinders.

For anything else I will need to use a camshaft to open and close valves which would be much more complicated, I still have not decided on where I should locate the camshaft. Flathead, pushrods, SOHC, DOHC... Slightly leaning toward SOHC as it seems like that would need the least amount of parts.