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Wartsila’s User Group Forums 34 SG Wartsila Engine Hot Bearing trip on “Deep Rolled” engine after overhaul Reply To: Hot Bearing trip on “Deep Rolled” engine after overhaul



Sorry for the delayed response, but we had a shutdown on high main bearing temperature, and found the cause to be a cracked shaft.  I can provide more details, but following is the way it showed up:  We had recently had a shutdown on high liner temperature, cyl 6A.  It was replaced with no identified cause.   After 21 hrs of runtime, we had an the engine trip on a high main bearing differential trip – Bearing #7 (adjacent to cyl 6A).  Found crankshaft cracked completely through.  The crack caused a local loss of oil pressure, starving cylinders 6A & 6B of oil, resulting in liner scoring. Main bearing 7 was affected as well, due probably to oil pressure and shaft alignment, since it was broken.  The crack ran directly through a repaired spot in the shaft where it had been ground and polished…prior to deep rolling.  The deep rolling tool could not properly deep roll that area because of the uneven surface where grinding took place.  This was determined to be the cause of failure.

Stephen Layton