[Bicycle Bob]

I just looked up the ancient rule of thumb for boilers, and it suggests that Crower would need about ten square feet of "boiler area" per horsepower. That's a lot of little holes in the head. In general, there's twice as much heat going out the exhaust as out the radiator.

It might be worth while to use some cylinders as steam engines at cruise power, and only burn fuel in them for maximum output. It is probably better than just turning them off with the piston still moving, as is sometimes done.