Abstract: An crank system-device is hereby designed, specifically for piston-type internal combustion engines, to maximize the transfer of combustion power from the push-down pressure of the piston 10 to the twisting force of the crankshaft 15b. It provides for a “Downward Power Path” 18b that enables the piston 10 to push the crank pin 14 downwards and close to the piston centerline 16, unlike in the case of the “Sideways Power Path” 18a of the Prior Art wherein the piston 10 pushes the crank pin 14-1 sideways and away from the piston centerline 16. To effect a downward power path, an “Off-Center Crankshaft” 15b is resorted to, whereby the crankshaft is moved from its usual position along the piston centerline 16 to the left side thereof, and with an offset distance that places the downward path 18b of the crank pin 14 directly under the piston's downward axis along the piston centerline 16.