To investigate the root cause of Diesel Engine #2 breakdown, assess the extent of damage sustained during offshore operation and voyage, and recommend Repair for the MAN engine along with preventive measures to avoid future failures.
Challenge / Problem Context
1. Crank Pin exhibited excessive hardness reduction and developed four cracks.
2. Main Journal showed excessive run-out beyond permissible OEM limits.
3. Severe bearing damage observed in connecting rod big-end shells due to metal flaking.
4. Lube oil cooler was leaking heavily at low pressures, indicating water ingress in oil.
5. Bearing shells showed cavitation, excessive flaking, and seizure symptoms
6. No lube oil change history or recent oil analysis was available, compromising preventive maintenance.
7. Abnormal torque detection and dents on counterweights possibly due to previous undetected foreign material impact.
8. Pending damage assessment remained for several components including connecting rods and main lube oil system.
What Did We Do?
1. Measured crank pin ovality and hardness; stopped grinding after discovering deep crack at 0.55mm on pin.
2. Measured true run-out of all main bearing journals; found journal exceeded limit and advised validation with OEM.
3. Inspected B1 and A1 big-end bearings; identified bearing rotation, seizure, and fatigue flaking; replaced and documented findings.
4. Performed pressure test on lube oil cooler and confirmed heavy water leak at just 3 bar (against required 15 bar); dismantled affected components.
5. Inspected connecting rods and bearings; observed excessive flaking and cavitation; confirmed beyond reuse condition.
6. Documented oil sump condition and collected metal debris; noted absence of lube oil change history and advised testing for emulsification and contamination.
7. Verified torque on unit counterweights; found torque acceptable but noted physical dents on B3 counterweight; no sump foreign object found.
8. Documented pending inspections for connecting rods, main lube oil pump, and foundation bolts to be included during engine re-commissioning.
Results That We Achieved
1. Successfully isolated and diagnosed crank pin crack origin, enabling the client to avoid further damage during grinding and plan for crankshaft evaluation.
2. Identified critical deviation in journal run-out at early stage; recommendation to engage OEM saved potential journal scoring during future operation.
3. Found and documented fatigue failure in big-end bearings; initiated steps for bearing type upgrades as per OEM modification bulletin.
4. Confirmed water ingress via cooler, correlating to observed oil emulsification; prompted emergency oil quality testing and initiated oil cooler replacement.
5. Prevented reuse of compromised connecting rods by early detection, thereby reducing risk of cascading failures in adjacent units.
6. Helped the customer understand the likely root cause—oil contamination—by linking bearing wear with cooler leak, poor oil maintenance, and suggested monitoring tools.
7. Eliminated the possibility of current foreign material impact, traced dents to earlier incidents, and re-torqued nuts to OEM standard.
