The Beare-head engine internal combustion engine technology combines a four-stroke engine bottom end with a ported cylinder head closely resembling that of a two-stroke engine. The head piston is smaller and moves at half the speed of the opposing piston. Functionally, the cylinder-head piston replaces the valve mechanism of a conventional four-stroke engine. This configuration has been described as a six-stroke engine based on adding together the four strokes per cycle of the bottom end and the two strokes of the cylinder head.
- "After 16 years' work –- the six-stroke engine" (PDF). Border Chronicle (Vol. 87 - No. 4365). Bordertown, South Australia. November 10, 1994. Archived (PDF) from the original on October 1, 2011.