SUCCESS!!!! Today I finished the second set of valves on the model compressor so it would be double acting and proceeded to make a video of it blowing up a balloon and bursting it. I used my Rockerblock engine this time, because it has a slightly larger pulley on it than my overhead cam engine. In the first video, the balloon got bigger, and bigger, and bigger but refused to pop, and I figured anybody watching might go to sleep before it burst, so the first video link is a technical fail.--Second time around, I set up the tripod for my digital camera, put a new balloon in place, opened my office door so I wouldn't gas myself, and started the engine and then got out of the way and let it run. Great success with the second video!! You can see that I was able to use an o-ring drive belt and avoid buying a costly timing belt drive set-up or using a sprocket and chain that would have been to big for the job. You will see however that it's right on the ragged edge--the pulley actually stops and the belt drive slips momentarily during each revolution.
[ame]https://www.youtube.com/watch?v=-_iqt3ecAZc[/ame]
[ame]https://www.youtube.com/watch?v=cTBajAJrRnU[/ame]