18V50SG “A” Series Cylinder Head Cracking

[Anonymous]

Of our 4 “A” series 18V50SG units, we have experienced two cracked cylinder heads. Each time the head cracked in the same place, in the intake valve tenon between the valves.  This allowed cooling water to leak into the combustion chamber, causing the affected cylinder to misfire on the first start attempt of the day, followed by a normal start on the second attempt.  This is not repairable per Wartsila, and the head must be scrapped.  The first occurred at 5564 hours, the second at 5345 hours.  These are peaking units, averaging 10-12 hours per start and are operated at 100% load.

Is this a common failure on the 18V50SG?  And is the “B” series cylinder head more reliable or less prone to cracking?

Thanks for any feedback.

Dave Mordecai, Hopkins Generating Station

[gastonduarte]

Hello Dave,

How are you?

In one of five 20V31SG sufered a damage in one cylinder head. Motor was tripped by “Cylinder in CCO mode”

An inspection was performed. a Crack in cylinder head of one cylinder was found. After that, the inspection was deepened and the following issues were found.

– Damage in PCC valve (stem damage)

– Strike in prechamber nozzle

– Damage in piston and cylinder liner

Could you please let me know if your motors continue with these issues about cracks? Did you received any feedback from manufacturer?

Thanks for any feedback

[Author]

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