This manual covers Lycoming O-235-C Series and O-290-D aircraft engines, designed as reciprocating, air-cooled, naturally aspirated powerplants with horizontally opposed cylinders. These engines are engineered for reliable propulsion in aircraft applications. The O-235 series features a displacement of 235 cubic inches (3.85 liters), while the O-290-D series offers 290 cubic inches (4.75 liters). Both models utilize a 4-cylinder configuration with a bore of 4.375 inches (111.12 mm) and a stroke of 3.75 inches (95.25 mm).

This Illustrated Parts Catalog (IPC), part number PC-101, provides comprehensive information for identifying and procuring all procurable parts for the specified Lycoming aircraft engines. It serves as an essential resource for owners, mechanics, and technicians to ensure proper maintenance, repair, and operational integrity of these propulsion systems. The catalog details the components necessary for the continued performance and longevity of the O-235-C Series and O-290-D engines.