The objective of this project is an attempt to experimentally determine the limit of performance of an inwardly-opposed, uncooled, two-stroke compression ignition engine.The basis for this design is the fabrication of an engine from two 4-53T Detroit Diesel Allison engines using one active cylinder. During the initial phase of operation, the engines will be cooled and will consist of the redesign of the engines, using standard parts, to operate in an inwardly opposed piston configuration. The second phase will consist of developing hardware to provide uncooled operation using current technology. This will include reconfiguring the piston and cylinder liner with ceramic material to permit uncooled engine operation.The elimination of the heat loss to the coolant does not in itself significantly increase the mechanical power transmitted through the piston. Instead, the energy conserved is combined in the exhaust energy which is usually unavailable. Turbocompounding is a technique which is used to recover a portion of this energy.The output of the cooled and uncooled engine will be compared to one another in terms of the performance parameters of thermal efficiency, volumetric efficiency, brake mean effective pressure and specific power (brake power per unit of piston area and brake power per unit of displacement volume).