John--A hit and miss engine takes on a lot more complexity than a simple 4 stroke engine because of the hit and miss mechanism. In order to make the engine "hit and miss" a governor must be built into the engine, with its associated levers, weights, pivot points, and sliding spool and springs. There is a caveat about building from castings.---If you are a relative novice at machining, and you totally mess up a cast part, then you have to replace the single casting, which is not always easy when the castings are sold as part of a kit. If machining totally from bar stock, and you screw up a part, then just grab another piece of the same barstock and start again. Internal combustion engines are not difficult. However, they have a set of issues that you won't run across in making steam or "air" powered engines. That is why I suggest something like the Webster as a first i.c. engine. --I have built 7 i.c. engines, and the Webster was my first. Building i.c. engines is a "cumulative knowledge" process. You start with a simple one, and apply what you learn from building it to a slightly more complex engine, and so on.-Brian
