Internal engine components in Cummins engines manage combustion, force transmission, and lubrication. Pistons convert combustion energy into linear motion. Connecting rods link pistons to the crankshaft under high stress. Crankshafts translate linear force into rotational energy. Camshafts control valve timing for precise airflow and exhaust. Bearings reduce friction between rotating and stationary parts. Cylinder liners provide wear-resistant surfaces for piston travel. Pushrods and lifters transmit motion from camshaft to valves. These components operate in extreme conditions requiring precise engineering and durable materials.