A piston insertion machine for inserting piston assemblies into respective cylinders of an internal combustion engine. The piston insertion machine eliminates the need for individually lifting and inserting the piston assemblies into the respective cylinders. The piston insertion machine includes a barrel assembly for holding the piston assembly. A first set of components pivot the piston barrel assembly (and thus the piston assembly) from an upright position to a horizontal position. Another component inserts the piston assembly into the cylinder of the engine block.