Lycoming O-360
The
Lycoming O-360 is an air-cooled, carbureted, four-cylinder, horizontally opposed piston aircraft engine.
Displacement is 361 cubic inches (5.9 liters). Bore and stroke are 5.125 and 4.375 inches (130 and 111 mm) respectively. Many minor variations exist, but perhaps the most common is the "high-compression" versions O-360-A series. They have an 8.5:1
compression ratio and are nominally rated at 180 horsepower at 2700 RPM at sea-level. They were originally type certificated on a short-lived 91/96 octane aviation fuel, but now are generally required to burn
100LL aviation fuel. Some installations allow for the substitution of automotive gasoline of 91 or higher
anti-knock-index (R+M)/2 rating.
A low-compression (7:1) version exists that nominally produces 168 horsepower at sea-level, but was installed in very few production aircraft. The O-360 is the slightly larger (identical bore, slightly stroked) version of the
Lycoming O-320.
Nominal maximum continuous cruising power for the 180hp version is 75%, which consumes approximately 9.5-10 gallons of fuel per hour.
The O-360 is generally considered to be quite reliable, with a typical TBO (Time Between Overhaul) of 2000 hours, though many have safely exceeded this number. They have been installed in thousands of aircraft including Cessna 172s, Piper Cherokees/Archers, Grumman Tigers, and many home-built aircraft.
A fuel injected version known as IO-360 which produces 180 hp is currently used in the Cessna 172SP. The fuel injection system eliminates the risk of carburetor ice, and requires a slightly different starting procedure than the carbureted version.
