Abstract: A magnet attracts succeeding sites distributed about the periphery of a disk causing the disk to rotate. The resulting centrifugal force pulls radially outwards a plurality of piston-like weights mounted on the disk lowering the pressure within a housing for the weights and in a vacuum tank to which the housing is communicated via a check valve. When the weights are all the way out, they operate a trip which renders the magnet temporarily ineffective. Springs return the weights back toward the center of the disk. The vacuum tank is communicated to an opposed piston engine via timed valves which alternately communicate the engine cylinders to the vacuum, for oscillating the opposed pistons. A crank shaft connected to these pistons converts the reciprocating motion to rotary motion.