Crankshaft Seized After a Diesel Generator Overhaul

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Incident : Crankshaft unable to Turn after Maintenance
Engine : Bergen Diesel KRG-6, 1032 kW, 720 rpm

A vessel had a serious breakdown of diesel generators and it was to the extent that the entire engine required a complete overhaul.  The vessel was laid up to bring the diesel generators back to life and power the ship.  The ship managers decided to carry out dismantling of both the diesel generators with the ship staff and the rebuilding work with shore engine experts.

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After about couple of week’s work, the shore technicians completed the rebuilding of both diesel generators.  After inspection and checks, the ship staff took new lubricating oil into the engine sump.  It was all set to try out the engine and check for proper working.  When the ship staff attempted to crank the engine, the engine did not turn.  The entire engine staff got puzzled as after all the hard work, the engine did not turn . The Shore experts were called to check on this peculiar case as to why the crankshaft was not rotating.

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The engine expert went through the complete list of work done by the ship staffs and the shore technicians.  There was no clue on why the crankshaft did not turn.  After a couple of hours, the engine expert asked for all the calibration records and found that the connecting rod ovality check was missed out.  The ship staff, as well as the shore technicians, did not check the connecting rod ovality.

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Finally, there was a ray of light at the end of the tunnel.  The entire team pulled out all the pistons and the engine expert calibrated the connecting rod for ovality.  All the connecting rods ovality exceeded the engine maker’s recommended limits.

If you are wondering what is connecting rod Ovality – Here is something which you can use to recollect your memories.

 

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This caused additional delay in the lay-up and the vessel was unable to meet the new charterers’ timeline.

Causes & Lessons Learnt:

  1. The complete job was not under a control of a single party.  The job was split into two groups. One the ship staff and the other shore technicians.
  2. Had the ship staff be vigilant, aware and guided the shore technicians properly, this time, the delay would have been avoided.
  3. The shore technicians are to be monitored and checked for their work procedures and adherence to engine maker’s guidelines are essential.
  4. Engine Maker’s recommendations and engine experts’ suggestions are to be strictly followed.
  5. Though the ship manager opted to rebuild the engine with the help of shore technicians, it is essential for the ship staffs to be on top of the situation when it comes to calibration of engine components.

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About the Author:

DSC_0603.jpgMr. Wolfgang Gensch has over 32 years of service experience with MAN B&W. Over the past 7 ¼ years while employed with MAN B&W, he has attended to more than 440 vessels for different purposes. In the past forty years, Mr. Gensch had attended to over 600 vessels and carried out different work covering all fields on diesel engines and turbochargers, from normal docking, to troubleshooting, to overhaul, repair and rebuilding work on older and newer engines.  His area of expertise is quite vast from a simple inspection up to intensive repair work such as repositioning of crankshafts on 2-stroke engines.  He is  Senior Technical Consultant at DETC – Singapore.

Any Engine Problem?

Consult Mr. Wolfgang through MFAME.

5 COMMENTS

  1. Any Engine Problem?

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  3. This is very normal problem and when tightening connecting rod bolts you will come to know that the con rod bearing will not be floating and crankshaft any way will not turn. You will come to know during tightening of connecting rod bolts. In 1989-90 we had the similar occurrence on Daihatsu HFO running Diesel generator and suppose to tighten up to 90 kg-m torque. After 45 kg m torque the connecting rod bearing stopped turning.
    As we do not have new or recon connecting rods we run the diesel generators at 45 kg m torque and reduced load on the engine.

    I was the 2nd Engineer on that ship and handled the job with my own hands. We run successfully the Diesel generators with 45 kg-m torque tightening and checking the con rod bolt locking’s and condition of connecting rod regularly. After received the new connecting rods we tightened back to 90 kg m.

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