Abstract: A prime mover is shown which can be used in supplying power for a variety of roles in industrial applications, including oil and gas well operations, such as the prime mover which is used to operate a pump jack at a well site. It includes an internal combustion engine having an output shaft, the engine being cooled by engine oil supplied from an oil reservoir to the engine and circulated by an oil pump. A housing framework encloses the engine and supports an associated jack shaft bearing assembly, and includes a base, a hood and a plurality of upright supports which extend upwardly from the base in the direction of the hood. One or more of the uprights is a specially designed compartment having a plurality of opposing sides which define an initially open interior space, the interior space comprising an integral oil reservoir for storing and supplying oil to the engine during normal engine operation.

Abstract: A prime mover is shown which can be used in supplying power for a variety of roles in industrial applications, including oil and gas well operations, such as the prime mover which is used to operate a pump jack at a well site. It includes an internal combustion engine having an output shaft, the engine being cooled by engine oil supplied from an oil reservoir to the engine and circulated by an oil pump. A housing framework encloses the engine and supports an associated jack shaft bearing assembly, and includes a base, a hood and a plurality of upright supports which extend upwardly from the base in the direction of the hood. One or more of the uprights is a specially designed compartment having a plurality of opposing sides which define an initially open interior space, the interior space comprising an integral oil reservoir for storing and supplying oil to the engine during normal engine operation.