An analytical treatment was conducted to investigate piston motion in a diesel engine and a computer program was written to predict optimum designs for high mechanical efficiency and low noise and vibration excitation due to offset settings of the crankshaft, piston-pin, and piston center of gravity. The results of the computer program are shown in three dimensional (3D) graphics to visualize the optimization results. From these 3D presentations, it can be easily seen which parameter is more sensitive and which is not. A semi-empirical formula to correlate the oil film pressure and piston skirt clearance has been developed. The measured and calculated values are presented to show good correlation.