A patent for a six-stroke engine would normally go directly into our crackpot-engine file, but when the patent filer is ...

More importantly, the 7.3 Power Stroke was a paragon of high-quality construction. It had forged connecting rods, cast iron cylinder heads, a steel crankshaft, and cast aluminum pistons.

The two outside, high-pressure cylinders work like a normal four-stroke, but alternate their exhaust flow into the third, central low-pressure chamber. That cylinder's expansion and compression ...