The Continental O-300 and the C145 are a family of air-cooled flat-6 aircraft piston engines built by Teledyne Continental Motors.[1]
First produced in 1947, versions were still in production . It was produced under licence in the United Kingdom by Rolls-Royce in the 1960s.
The C-145 was developed from the 1250NaN0 C-125 engine. Both powerplants share the same crankcase, although the C-145 produces an additional 20hp through a longer piston stroke, higher compression ratio of 7.0:1 and different carburetor jetting.
The O-300 is a modernized C-145 and retains the same weight, dimensions, bore, stroke, compression ratio, displacement and output power of the earlier engine.
The GO-300 employs a reduction gearbox, so that the engine turns at 3200 rpm to produce a propeller rpm of 2400. The GO-300 produces 1750NaN0 whereas the ungeared O-300 produces 1450NaN0.
The GO-300 engine has a TBO (Time Between Overhaul) of 1200 hours, while 1800 hours is the standard for ungeared O-300 engines. The GO-300 engine suffered reliability problems as a result of pilots mishandling the engine and operating it at too low an engine rpm. This caused the Cessna Skylark to develop a poor reputation for engine reliability. Many Skylarks flying today have been converted to different, larger-displacement, direct-drive engines.[2]
Reference: Engines for Homebuilt Aircraft & Ultralights