The Lycoming R-680 is a nine-cylinder air-cooled radial engine, the first engine produced by Lycoming. The engine was produced in two types the E and B series both are essentially the same, the B4E was available in a trainer version with a front exhaust collector for use without cylinder air baffles.

Variants

R-680-B4E
Rated at 225hp at 2100 rpm.
R-680-E3A
Rated at 285hp at 2200 rpm.

Specifications:
General characteristics:
* Type: Nine cylinder air-cooled radial
* Bore: 4 5⁄8 in (117 mm)
* Stroke: 4 1⁄2 in (114 mm)
* Displacement: 680 in³ (11.15 litres)
* Length: 37.5 in (953.1 mm)
* Diameter: 43.5 in (1104 mm)
* Dry weight: 515.46 lb (233.9 kg)

Components:
* Valvetrain: One inlet and one exhaust valve per cylinder at 30 degrees.
* Fuel system: single-barrel carburetor
* Fuel type: 87 octane rating gasoline
* Oil system: Full pressure type
* Cooling system: Air-cooled

Performance:
* Power output: 330 hp (246 kW) at 2,300 rpm at sea level
* Compression ratio: 7:1
* Power-to-weight ratio: 0.64 hp/lb (1.05 kW/kg).

Source: Wikipedia.org.