An Oil Mist Detector high oil mist alarm tripped the engine (MAN B&W 48/60 V). A crank case explosion hit after the engine shaft stopped rotating. Crankcase relief valves actuated and filled the engine room with a white oil mist. It was investigated that the piston pin had parted in two pieces. The piston cracked and a part broke off around the circlip groove. The liner was severely damaged and the piston pin bearing destroyed. The cause was found to be the low quality metal material used in the manufacture of the piston pins. All pins from the same supply were renewed.
posted 09 Jun '17, 04:13