If that's the case, you are right. It is not an engine. If it was intended to operate as one, it would have proper gearing for the cams. They should operate at half engine speed, and they don't. That's not to minimize how nice the workmanship is. It's just not a functional model.
I beg to differ. It may not be an internal combustion engine, but it's a working engine. He's running it on compressed air (I think) but could easily run it on steam.
Besides, the valve cam gears are valid for a 2-stroke diesel.
I probably should have expressed myself better than I did. I realize the "engine" runs on air, and most likely would run on steam, but it does not, and can not, run on fuel (as an internal combustion engine) which was my point. As has been stated, much smaller engines have been built that can, and do.