Abstract: The engine is of the continuous combustion type having two multiple piston banks separated by a centrally disposed undulating spider drive member operated from the piston action and adapted to drive the output power shaft of the engine. The engine comprises a water-jacketed block defining preferably eight cylinders in each bank for receiving eight pistons in each bank. Aligned pistons of respective banks are interconnected in a linear non-rotatable arrangement with the spider drive member. The spider drive member is continuously skewed to the output shaft, includes bearing means and operates on an eccentric basis driven from the piston connecting rods on a timed basis. The output power shaft supports a rotor defining valving ports including upper and lower intake ports and a transfer port. The gas-air carburization occurs within the rotor with the use of a porous medium.