page_title: Lycoming O-320
section_title: O-320 series
hierarchical_section_title: Lycoming O-320 / Variants / O-320 series
caption_attribution_description: English: Robinson R22 Beta; Aviosuperficie FlyRoma. Lycoming O-320 engine detail Italiano: Robinson R22 Beta; Aviosuperficie FlyRoma. Dettaglio motore Lycoming O-320
context_page_description: 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.
context_section_description: O-320 (No suffix) later redesignated O-320-A1A
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Provisions for a controllable-pitch propeller and 25-degree spark advance.
  O-320-A1B
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as A1A but with straight riser in oil sump and -32 carburetor.
  O-320-A2A
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as A1A but with fixed-pitch propeller.
  O-320-A2B
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as A2A but with straight riser in oil sump and -32 carburetor.
  O-320-A2C
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as A2B but with retard breaker magnetos.
  O-320-A2D
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as E3D but with conical mounts.
  O-320-A3A
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as A1A but with 7/16" prop bolts.
  O-320-A3B
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as A3A but with straight riser in oil sump and -32 carburetor.
  O-320-A3C
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Same as A3B but with retard breaker magnetos.
  O-320-B1A
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as A1A but with high compression pistons.
  O-320-B1B
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as B1A but with straight riser in oil sump and -32 carburetor.
  O-320-B2A
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as B1A but with fixed-pitch propeller provisions.
  O-320-B2B
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as B2A but with straight riser in oil sump and -32 carburetor.
  O-320-B2C
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as B2B but with retard breaker magnetos.
  O-320-B2D
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 91/96 avgas, compression ratio 8.50:1. Same as D1D but with conical engine mounts and no propeller governor.
  O-320-B2E
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 91/96 avgas, compression ratio 8.50:1. Same as B2B except the carburetor is in the same location as the O-320-D models.
  O-320-B3A
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as B1A but with 7/16 inch propeller bolts.
  O-320-B3B
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as B1A but with 7/16 inch propellor bolts, a straight riser in oil sump, and -32 carburetor.
  O-320-B3C
  160 hp (119 kW) at 2700 rpm, Minimum fuel grade 100/130 or 91/96 avgas, compression ratio 8.50:1. Same as B3B but with retard breaker magnetos.
  O-320-C1A
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Low compression version converted through field conversion of B1A.
  O-320-C1B
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Low compression version converted through field conversion of B1B.
  O-320-C2A
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Low compression version converted through field conversion of B2A.
  O-320-C2B
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Low compression version converted through field conversion of B2B.
  O-320-C2C
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Low compression version converted through field conversion of B2C.
  O-320-C3A
  150 hp (112 kW) at 2700 rpm, Minimum fuel grade 80/87 avgas, compression ratio 7.00:1. Low compression version converted through field conversion of B3A.
  O-320-C3B
  150 hp (112 kW) 
caption: An O-320-B2C mounted in a Robinson R22 helicopter
exif: {"Image Make": "NIKON CORPORATION", "Image Model": "NIKON D70", "Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Ver.2.00", "Image DateTime": "2008:04:19 12:16:04", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "216", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "300", "Thumbnail YResolution": "300", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "29524", "Thumbnail JPEGInterchangeFormatLength": "8719", "Thumbnail YCbCrPositioning": "Co-sited", "EXIF ExposureTime": "1/200", "EXIF FNumber": "10", "EXIF ExposureProgram": "Unidentified", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2008:04:19 12:16:04", "EXIF DateTimeDigitized": "2008:04:19 12:16:04", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "43/10", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "70", "EXIF SubSecTime": "70", "EXIF SubSecTimeOriginal": "70", "EXIF SubSecTimeDigitized": "70", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3008", "EXIF ExifImageLength": "2000", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "29386", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CVAPattern": "[0, 2, 0, 2, 2, 1, 1, 0]", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "105", "EXIF SceneCaptureType": "Landscape", "EXIF GainControl": "None", "EXIF Contrast": "Soft", "EXIF Saturation": "Normal", "EXIF Sharpness": "Hard", "EXIF SubjectDistanceRange": "0"}