Torsional vibrations are inherent within diesel engines, due to the varying torque produced by the piston and crank arrangement from each cylinder. This torque variation is further compounded by the arrangement of the firing order of the crankshaft.
The effects of such vibrations is to increase the shear stress and hence total stress levels carried by the crankshaft in service, when other stresses such as bending and combustion loads are present.   _{Your Comment}