The first point of understanding in the difficulties in distinguishing the quality of the cylinder liners is the performance and the durability traits of the liner. For better performance in both thermal conductivity and wear resistance select liners of cast iron or aluminum. Again, focus on how it was manufactured; advanced techniques such as CNC machining also aid in the uniformity of the results. Lastly, most factors engineers consider are the specified dimensional information given by manufacturers i.e thicker wall features as well as surface structure to be treated. These attributes greatly affect the ability of the liner to retain the engine.