Abstract: A production line for mechanically assembling pistons into cylinders of an internal combustion engine block and for automatically mounting the split bearing for each piston connecting rod to the crankshaft of the engine. At one end of the line, the engine block is laid on end with the piston cylinders extending horizontally. A magazine with a generally cylindrical sleeve in alignment with each cylinder bore in the engine is supplied with pistons complete with connecting rods. The connecting rods are positioned facing the top of the engine block. A split bearing end cap for each piston is placed in suitable holders on the sides of the magazine. At one station of the line, a ram automatically pushes one or two pistons into the engine block. A nesting receiver is positioned to receive the end of a connecting rod and guide the bearing end of the rod onto the crankshaft. Thereafter the bottom split bearing end cap is carried to the crankshaft for connection to the top end cap of the connecting rod.