[fargon]

My quick google search, brought me back to the same article. There are many reversible diesel engines, Atlas Imperial, and B-W diesel marine engines.
To reverse an engine, you stop the engine, line up the timing marks, rotate the cam shaft 180 degrees, and re-start it the opposite direction. Since most magnetos don't like turning backwards, you would need a mag. for reverse operation. This would be a complex engine to operate, but would put out the same power in reverse as well as forward.
One way of doing this is with two camshafts making for a complicated valve train. I'm gonna look into this engine, and see what I learn.