One cannot directly equate the "energy capacity" of steam to that of combustion. If we were talking about a 1 cycle gasoline engine this argument might be made; but steam is something entirely different. The potential power of one of these engines is not yet known. It depends primarily on two things. The amount of energy stored in the steam to be injected into the cylinder, and the amount of time necessary for this energy to be released inside the cylinder. A gasoline engine has a much smaller volume and stroke length than a standard piston steam engine, and normally runs at much higher RPM than conventional steam engines. All this acts against my design as far as power goes. At the moment, I am researching the mathematics of steam power so as to calculate what can be expected from this design and to indicate ways to optimize it.
For the reasons described above, and because of the difficulty in constructing the new cam shaft, I really don't have much hope for engine design #1. I am, however quite hopeful for the prospects of design #3, which is a simplification of design #2. Designs #2 and #3 utilize electric actuated valves built for steam use, the engine's existing distributor mechanism with some simple modifications, and a controller that's electronic; but great pains are being made to keep it simple and enable it to be constructed using electronic parts found in such things as TV circuit boards.