You have some very useful information here, and I agree with what you're trying to do. I disagree with some of your basis, however.
You are correct that the cam gear is TWICE the size of the crank gear, but that also means the camshaft revolves Half the speed of the crank.
Mathematically, this is a 4-stroke engine which means the intake valve for a given cylinder only opens every other crank revolution, but you don't have to take MY word for it.
http://en.wikipedia.org/wiki/Four_stroke_engine<br class="Apple-interchange-newline">
