The most common error in a "cranks OK- - - -won't start" situation is firing the spark plugs at the wrong point in the 4-stroke cycle. The pistons reach the top of the stroke twice (and the timing marks line up) on both the compression and the exhaust stroke. It's easy to get the timing "180 degrees out" if the distributor or the spark plug wires have been tinkered with. There's an idiot-proof way to get it right, but it involves removing the valve cover. Most people would rather guess about it than do that.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!