Oil Field Engine News

Tracking the Elusive Black Bear


| April/May 2004



Black Bear

One of the rarest oil field engines is the 'Black Bear' sold by the Oil Well Supply Co. of Pittsburgh, Pa. Of side shaft design, Black Bear engines are very pleasing to the eye thanks to their many moving parts while in operation.

Black Bear engines were ahead of their time with features such as mechanically actuated intake valves, optional air starting, a water pump and a triple-redundancy ignition system. Engines were built in 25, 35 and 40 HP sizes.

One thing I don't know for sure is whether Oil Well Supply actually manufactured these engines, or if they were sourced from another company. Existing engines are few, but I was fortunate to track down a circa-1920 Oil Well Supply Co. brochure that describes the engines:

Black Bear Gas Engines

'Black Bear gas engines are designed to meet the most severe requirements in the oil country. All parts are made with a view of exceeding the strength actually required.

'The engine is of the four-cycle type with valve mechanism operated by a camshaft driven by spiral gears from the main shaft. Both inlet and exhaust valves are operated by the same cam.

'Governing is effected by means of a Pickering governor, which can be set to operate the engine at a fixed speed or can be controlled by a line operated from the derrick floor.