Computer based analytical design techniques are transforming the engine design process. Analytical tools allow faster and more accurate design optimization. The design process is also shortened because the electronic transfer of files permits the design to be worked concurrently by engineers working with different analysis packages or on various parts of the design. Prototype parts and tooling can be made directly from the Computer-Aided Design (CAD) by various rapid prototyping methods.The analytical design techniques can also permit a highly optimized design with less possibility of corrections being necessary in the development stages. This paper reviews these new design techniques and examines how they can be used to improve the design technique.The following design tools are discussed. Engine Simulation Programs, Techniques that make full use of current CAD systems, Rapid prototyping, Finite element modeling, Computational fluid dynamics, Friction and wear analysis, Component reliability analysis, Bearing calculations, System kinematic and dynamic modeling.