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Wartsila’s User Group Forums 50 SG Engine Broken crankcase cover bolt

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  • #1991

    Putting this out there as an FYI for the 50SG user’s:

    Over the weekend a crankcase access cover loosened on one of our 50SG units, creating an oil leak that was quickly dealt with by our nightshift operators.  Suspecting that these covers may not have been properly torqued to the 150nm spec called out in the manual, we set about to check the torque on all crankcase cover bolts.  One snapped off at far less than 150nm, creating an instant oil leak on the running engine.  The engine was shut down and, not having a spare, we drilled and tapped the broken stub to 1/2″-13 and secured the cover with a grade 8 bolt and heavy washer.  It’s been holding since Sunday, and we’ve ordered a small quantity of part # 107 076 in case of  another failure.   It was not a Wartsila recommended spare, so none had been stocked.

    This was clearly a defective part, as an M24 grade 8.8 bolt is rated for 640nm.

    I’m curious to see if anyone else has seen a similar failure.



    We have been dealing with this since startup. We have had a couple dozen fail while the engine is running or when they are installed after an inspection. We keep a handful on the shelf. Most of the breakage we have is when we install the cover after an inspection. There are a number of parts we have chosen to stock that are not on the recommended spare parts list.

    Ruben Tellez

    We do have broken crankcase cover doors bolts maybe around 6 and we are close to 6k hours in the engines.

    One thing I will recommend is not to use impact tools on them, we minimize the usage of the impact guns.

    We normally keep 4 in the shelf just in case.

    There is lot of parts that are not in the critical list that you will eventually need.


    Follow-up to my first post:  We’ve sourced US-made M24 x 90 bolts from our local Fastenal and turned them on the lathe to match the reduced-shank profile of the Wartsila bolts.

    After having 2 of the OEM bolts snap off in service and forced units offline, we decided the OEM bolts were unreliable and sought alternatives.   And yes, these were all hand-torqued to spec.

    Dave Mordecai

    City of Tallahassee Hopkins Station

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