Yep, that hose seems to be for compressed air. Even a diesel would need some kind of heat source to get started, and I didn't see any glow plugs. It would also need a lot of compression, which means head gaskets, piston rings and other parts I couldn't see that he used. Still, that's an amazing piece. Just imagine making all those tiny rocker arms, all exactly the same... "Ok, one down, 23 to go..."
