Abstract
Periodically changeable gas and inertia forces which occur during operation of engine generate transverse, axial and torsional vibrations of crankshafts of multi-cylinder combustion engines. Torsional vibrations are those which endanger crankshafts of multicylinder combustion engines the most. In order to minimize their impact a torsional vibration damper is installed at crankshaft's free end. Its technical state directly influences lifetime and reliability of engine. In this paper methods of diagnosing, maintenance and regeneration of torsional vibration dampers used in shipbuilding, are discussed. Also, are presented results of multi-year statistical investigations carried out in cooperation with a firm maintaining and regenerating ship engine torsional vibration dampers, which illustrate types of failures occurring in viscous and spring torsional vibration dampers.