A reciprocating expander is one type of expander which may be applicable to an automotive Rankine cycle engine. Single cylinder reciprocating expanders were designed and fabricated for the purpose of evaluating solid lubricants and other supporting materials. For high engine efficiency, steam pressure and temperature up to 1000 psia and 1000 F, respectively are necessary. Several lubricants and wear resistant materials were tested in both a crosshead piston and trunk piston configuration. Also a specially compounded water resistant synthetic hydrocarbon oil was evaluated as a crankcase bearing lubricant. Both the crosshead piston and trunk piston expanders were fabricated and tested over a range of conditions depicted as follows: (1) speed range, 500-2000 RPM; (2) inlet steam temperature, 700-1000F; (3) inlet steam pressure, 400-1000 psia; and (4) condenser pressure approximately 20 psia. (Modified author abstract)