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The problem of crankshaft torsional vibrations is inherent to the reciprocating internal combustion engines. Till date, in multi-cylinder internal combustion engines torsional vibrations which increases vibratory torque is the major reason for the failures of crankshaft due to raised fillet stresses. The torque applied to crankshaft is not constant in time, but it varies in a complex manner as a function of crankshaft position for each cylinder. The excitation that causes torsional vibrations of crankshaft is the Gas firing pulse phasing in the cylinders of an engine. The Crankshaft natural frequencies get excited several times through out the operating speed of engine by different components of firing pulse harmonics, called orders of an engine. The vibration amplitudes at these critical speeds are commonly high enough, so that the crankshaft as well as any accessory coupled to the crankshaft may fail.