Introduced in 1957, the O-540 is one of Textron-Lycoming's best-selling piston engines. The O-540 is basically a six-cylinder version of the four-cylinder O-360. The eight-cylinder O-720 rounds out this engine family.
Current versions include direct injection and many are turbocharged.
models

• AEIO-540: 260 hp (194 kW)
• AEIO-540-L1B5: 300 hp (223 kW)
• IGSO-540-B1A: 380 hp (283 kW)
• IO-540-K1E5: 310 hp (231 kW)
• O-540-A1A: 250 hp (186 kW)
• O-540-B: 235 hp (175 kW)
• O-540-B2B5: 235 hp (175 kW)
• VO-540-A1B: 323 hp (241 kW)

specifications

• Horizontally opposed, 6 cylinder, piston engine
• Air-cooled
• Displacement: 541 cubic inches  (8.9 litres)
• Bore x stroke: 5.125 x 4.375 inches

used by

• Aero Commander Grand Commander
• CallAir A-9
• Bellanca 17-31 Super Viking
• Extra 300
• Hiller UH-12 Raven
• Piper PA-23-250 Aztec
• Piper PA-24-250 Comanche
• Piper PA-25 Pawnee
• Pitts Special