Lycoming Aircraft Engine O-145-B2

The Lycoming O-145-B2 (rated 65hp at 2550 rpm) was designed and built by the Lycoming Aviation Engines Company in Williamsport, Pennsylvania as part of their direct drive, air-cooled O-145 engine series in the late 1930s. The engine is has a four-cylinder, horizontally-opposed layout with a displacement of 144.4 cu. in. with dual magnetos. The engine is unusual in that the cylinders are integral to the crank case.

Used on a number of light aircraft in the 1930s including: Aeronca Chief, Piper J-3L Cub, Piper PA-15 Vagabond, Luscombe 8B, Taylorcraft BL-12 and Porterfield LP-65.

This engine was restored in 2020 to running condition by the students of instructor Paul Agaliotis in Gavilan College’s Aviation Maintenance Department.

Engine NameLycoming O-145-B2
Manufactured byLycoming Aviation Engines Company
Cylinder Configurationhorizontally-opposed
Number of Cylinders4
Bore (inches)3.625
Stroke (inches)3.5
Displacement (cubic inches)144.4
Horsepower65hp @ 2550 rpm
Compression Ratio6.5:1
Dry Weight (lb)163

We also have a cutaway example of this type of engine where you can turn the prop and see how it works.