Engine manufactures are continuing to develop new engine designs that provide higher power output, lower fuel consumption and lower engine weight.In order to achieve significant engine weight reduction, the light weight cylinder block structure employs dry cylinder liners rather than wet cylinder liners. The cast iron dry liner structure is utilized because of the superior wear and scuff resistance of the cast iron. Thin wall dry cast iron liners are being employed in both gasoline and diesel engines. Dry cylinder liners with wall thickness of 1.5mm are in production for Japanese automotive diesel engines.In the case of the dry thin wall cast iron liners, two(2) design configurations are employed: Loose-fit type having a specified clearance between the outer liner surface and the cylinder bore surface. Press-in type having an interference fit between the outer surface of liner and the cylinder bore surface. The physical properties of cast iron must be considered during the design phase if successful production designs are to be provided. In addition the operating stress caused by piston slap, combustion pressure variation and resultant effect on operating stress in the liner must be considered during the design.This paper summarizes the results of a series of studies undertaken to determine the effect of piston slap, combustion pressure and initial stress on resultant behavior of thin wall cylinder liners under engine operating conditions.The resultant data may be utilized to improve the overall design of thin wall dry cylinder liners. Especially for loose-fit liners.