Abstract: A radial internal combustion engine comprises an engine housing and a plurality of piston-cylinder pairs arranged on the periphery of the housing. The piston-cylinder pairs are arranged in two rows, three cylinders in each row. A connecting rod connects each piston to the crankshaft axially disposed within the engine housing. The connecting rods terminate in an arcuate flange. The connecting rods in each row of cylinders lie in a common plane equally sharing the crankshaft journal bearing surface. Lubrication about the crankshaft journal is provided through an oil flow passage which extends through the crankshaft for lubricating the crankshaft journal an the valve train of the engine.