I ran into an article in the November 1948 issue of Popular Science magazine on page 226. Which had a diagram and short article on converting one of the old vacuum type windshield wiper motors into a steam engine. I picked up a used vacuum type vacuum motor off of eBay to give this a try. The seals seemed to be good and would make a sucking sound when I manually turned the crank back and forth. I hooked an air line to the exhaust of the motor and it would push the crank in one direction only and would not switch over and push in the opposite direction. Not sure if this means the wiper motor is bad or if it is missing some mechanism for switching the air flow from one side of the chamber to the other. I've seen some videos on YouTube of two different versions of this concept working. Anyone have any suggestions for what I might be doing wrong or how to properly test this vacuum motor to see if it is working properly? After the failure of the vacuum wiper motor I picked up a vintage 1950's after-market type of electric windshield wiper motor fairly cheap and decided to substitute this for the vacuum motor to make a simulated steam engine running on 6 volts DC. This turned into another failure as there is a bit of variation in the start-stop-reverse points in the motor's operation which would not properly convert the oscillating motion of the wiper motor into rotational motion to spin a flywheel via the connecting rod and crank shaft.