Slobodyanyuk I. Increase of longevity of ship diesels with the picked up thread heads of pistons

Paper presents new solution of task of increase of longevity of exploitation of marine diesels by means of providing nominal parameters of working process due to closeness of cylinders working space. The increase of the piston heads longev-ity is provided on the stages of renewing and technical service. The aim is achieved by the development of the method of shortening the wear of piston cap ditches. On the basis of theoretical and experimental research main laws of change of operating properties of piston caps ditches were found at creation white layers on their surfaces, that allowed to increase the longevity of the engines due to con-trol of these properties. The investigation of longevity of piston caps of low speed MAN diesels were executed on 7 ships that lasted more than 8 years; they showed that improvement of technical service and repair of piston caps with white layers allow to increase the resource up to 11-11.5 thousand hours and in case of using the rings of repair size - up to 19.5-20 thousand hours.