An air motor (10) that has opposing chambers (16, 17) to which compressed air is alternatively delivered to drive the motor (10). The motor (10) has a primary valve (52) that governs deli very of the compressed air to the chambers (16, 17) so at least part of the compressed air is transferred to the other chamber to aid in driving the pistons (18).

An end cap assembly for a reciprocating air motor comprises a pilot valve and an end cap body. The pilot has a valve stem. The end cap body comprises a central bore for receiving an air motor rod, a valve bore in which the pilot valve is disposed such that the valve stem extends through the end cap body, and an air port extending through the end cap body. The air port has a contour to direct air toward the valve stem.