This manual covers Lycoming aircraft engines, specifically models O-235-C and O-290-D. These reciprocating, air-cooled engines are designed for aircraft propulsion and utilize internal combustion, running on Aviation Gasoline (Avgas). The O-235-C features a displacement of 235 cubic inches, while the O-290-D has a displacement of 290 cubic inches. Both engines are characterized by a horizontally opposed, 4-cylinder, naturally aspirated configuration. Lycoming Engines is the manufacturer of these robust and reliable powerplants, intended for demanding aviation applications.

This Parts Manual, in English and format PC-101, provides essential information for identifying and managing components for the Lycoming O-235-C and O-290-D aircraft engines. It is designed to assist owners, mechanics, and technicians in understanding the engine's structure and ensuring its continued operational integrity. While this manual focuses on parts identification, users are advised to consult specific Engine Overhaul Manuals or Service Bulletins for detailed maintenance procedures, including recommended oil types.