Failure analysis of a diesel engine

This paper presents the failure analysis of a diesel engine with 16 cylinders in V and 592 liters of displacement that was used for electric power generation, which failed at 27,000 hours of service. The study was performed by visual inspection and macroscopic examination of fractured elements, from which it was determined that the origin of the failure was the fracture by fatigue of one of the four B3 cylinder crown bolts whose fracture propitiated the failure of the other three bolts, so that the crown fell into the cylinder combustion chamber blocking the displacement of the piston, generating the buckling and fracture of the piston rod. The chemical composition, Brinell hardness and microstructural analysis of the crown bolts determined that the fatigue of the B3 cylinder crown bolt was due to an excessive tightening torque during its installation process which generated high stresses that, together with a lower fatigue strength caused by a slightly lower hardness in the failed bolt, produced the crown bolt fracture.