During inspection of a cylinder of a large slow speed diesel engine it is noted that there are hard deposits around the upper part of the piston crown above the top ring groove and also some evidence of scuffing on the liner wall.
What is the most likely cause of this problem?
Cylinder oil TBN is too high for the fuel grade in use.
Check residual TBN of under piston space drains, select correct CLO grade based on observation and Manufacturer's recommendations.
