Lycoming O-320


The Lycoming O-320 is a large family of naturally aspirated, air-cooled, four-cylinder, direct-drive engines produced by Lycoming Engines. They are commonly used on light aircraft such as the Cessna 172 and Piper Cherokee. Different variants are rated for 150 or 160 horsepower. As implied by the engine's name, its cylinders are arranged in horizontally opposed configuration and a displacement of 320 cubic inches.

Design and development

The O-320 family of engines includes the carbureted O-320, the fuel-injected IO-320, the inverted mount, fuel-injected AIO-320 and the aerobatic, fuel-injected AEIO-320 series. The LIO-320 is a "left-handed" version with the crankshaft rotating in the opposite direction for use on twin-engined aircraft to eliminate the critical engine.
The first O-320 was FAA certified on 28 July 1953 to CAR 13 effective 5 March 1952; this same engine was later re-designated, without change, as the O-320-A1A. The first IO-320 was certified on 10 April 1961, with the AIO-320 following on 23 June 1969 and the first aerobatic AEIO-320 on 12 April 1974. The LIO-320s were both certified on 28 August 1969.
The O-320 family of engines externally resembles the Lycoming O-235 and O-290 family from which they were derived. The O-320 shares the same stroke as the smaller engines, but produces more power with the bore increased to. The design uses hydraulic tappets and incorporates the provisions for a hydraulically controlled propeller installation as well. The controllable-pitch propeller models use a different crankshaft from those intended for fixed-pitch propellers.
The O-320 uses a conventional wet sump system for lubrication. The main bearings, connecting rods, camshaft bearings, tappets and pushrods are all pressure lubricated, while the piston pins, cylinder walls and gears are all lubricated by spray. The oil system is pressurized by an accessory-drive mounted oil pump. A remotely mounted oil cooler is used, connected to the engine by flexible hoses.
The versions of the carbureted O-320, are approved for the use of 87 AKI automotive gasoline. Only one model of the variants of the 0-320 is not approved, and that is the H2AD model. All other 0-320s are approved for 91 AKI. Airframe approval is also necessary to use automotive gasoline in any certified aircraft.
The factory retail price of the O-320 varies by model. In 2010 the retail price of an O-320-B1A purchased outright was USD$47,076

Variants

O-320 series

;O-320 later redesignated O-320-A1A
;O-320-A1B
;O-320-A2A
;O-320-A2B
;O-320-A2C
;O-320-A2D
;O-320-A3A
;O-320-A3B
;O-320-A3C
;O-320-B1A
;O-320-B1B
;O-320-B2A
;O-320-B2B
helicopter
;O-320-B2C
;O-320-B2D
;O-320-B2E
;O-320-B3A
;O-320-B3B
;O-320-B3C
;O-320-C1A
;O-320-C1B
;O-320-C2A
;O-320-C2B
;O-320-C2C
;O-320-C3A
;O-320-C3B
;O-320-C3C
;O-320-D1A
;O-320-D1B
;O-320-D1C
;O-320-D1D
;O-320-D1F
;O-320-D2A
;O-320-D2B
;O-320-D2C
;O-320-D2F
;O-320-D2G
;O-320-D2H
;O-320-D2J
;O-320-D3G
;O-320-E1A
;O-320-E1B
;O-320-E1C
;O-320-E1F
;O-320-E1J
;O-320-E2A
;O-320-E2B
;O-320-E2C
;O-320-E2D
;O-320-E2F
;O-320-E2G
;O-320-E2H
;O-320-E3D
;O-320-E3H
;O-320-H1AD
;O-320-H1BD
;O-320-H2AD
;O-320-H2BD
;O-320-H3AD
;O-320-H3BD

IO-320 series

;IO-320-A1A
;IO-320-A2A
;IO-320-B1A
;IO-320-B1B
;IO-320-B1C
;IO-320-B1D
;IO-320-B1E
;IO-320-B2A
;IO-320-C1A
;IO-320-C1B
;IO-320-D1A
;IO-320-D1B
;IO-320-D1C
;IO-320-E1A
;IO-320-E1B
;IO-320-E2A
;IO-320-E2B
;IO-320-F1A

LIO-320 series

;LIO-320-B1A
;LIO-320-C1A

AIO-320 series

;AIO-320-A1A
;AIO-320-A1B
;AIO-320-A2A
;AIO-320-A2B
;AIO-320-B1B
;AIO-320-C1B

AEIO-320 series

;AEIO-320-D1B
;AEIO-320-D2B
;AEIO-320-E1A
;AEIO-320-E1B
;AEIO-320-E2A
;AEIO-320-E2B

Applications

Specifications (O-320-A1A)