Project Type
12,000 Running Hours Major Overhaul
Engine Type: Pielstick (MAN / SEMT Pielstick)
Application: Power Generation – Medium-Speed Diesel Engine
Overview
INJEGOV successfully carried out a 12,000 running hours major overhaul on a Pielstick medium-speed diesel engine, following the manufacturer’s maintenance schedule and OEM technical guidelines.
The project included full disassembly, inspection, reconditioning, reassembly, testing, and commissioning, restoring the engine to optimal operational condition and ensuring long-term reliability under continuous load.
This overhaul formed part of a planned preventive maintenance program, designed to maximize engine lifespan, maintain performance efficiency, and minimize the risk of unplanned downtime.
Crankshaft, Bearings & Crankcase
Cylinder Heads & Valve Mechanism Overhaul
Pistons, Liners & Connecting Rods
Fuel Injection System Overhaul
Pistons & Connecting Rods
Cylinder Heads & Valve Mechanism Overhaul
- Complete removal and refitting of all cylinder heads|
- Full disassembly, cleaning, and inspection of components
- Hydraulic pressure testing and non-destructive testing (dye penetration)
- Reconditioning of exhaust and inlet valves, valve seats, and guides
- Replacement of worn valve bodies, sealing rings, and rotocaps
- Machining and restoration of gasket and sealing surfaces
- Rocking gear inspection and reconditioning
- Final tappet clearance adjustment according to OEM specifications
Fuel Injection System Overhaul
- Removal and refitting of injectors and injection pipes
- Injector calibration, atomization, and tightness testing
- Reconditioning and inspection of fuel injection pumps
- Timing adjustment using calibrated shims
- Final synchronization to ensure uniform peak cylinder pressures
Pistons, Liners & Connecting Rods
- Extraction and inspection of all cylinder liners
- Dimensional measurement, ovalization checks, and dye penetration testing
- Honing of liners to restore surface finish
- Repair of liner cooling grooves where cracks were identified
- Complete piston overhaul including:
– Cleaning and inspection of piston crowns and skirt
– Measurement and restoration of piston grooves
– Replacement of piston rings
– Clearance verification before and after reconditioning - Connecting rod inspection, MPI testing, and bearing shell replacement
- Verification of clearances between crankpin and connecting rod shells
Crankshaft, Bearings & Crankcase
Two heat exchange systems were serviced during the project:
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Main Engine L.O. Cooler (183 plates) — cleaned chemically in situ via recirculation
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Auxiliary Condenser — mechanically cleaned, inspected, and reassembled with new gaskets
Both systems were restored to maximum cooling efficiency and operational reliability.
Timing Gear & Auxiliary Systems
- Inspection of cams, tappets, rollers, and push rods
- Timing gear backlash measurements and verification
- Replacement of oil seals and worn sleeves
- Overhaul of lubrication, fuel oil, fresh water, and starting air systems
- Overhaul and hydraulic testing of air coolers
- Cleaning of cooling jackets and sump tank
Quality Control & Testing
A comprehensive quality assurance and testing process was applied throughout the overhaul, including detailed dimensional measurements recorded before and after reconditioning, non-destructive testing (NDT) on critical components, hydraulic and leak testing of cylinder heads and liners, and verification of all mechanical clearances against OEM tolerance limits, ensuring full compliance with manufacturer specifications and reliable operation in a power plant environment.
Engine Trials & Commissioning
After reassembly, the engine underwent:
- Controlled running-in procedure
- Load trials at 14.4 MW and 17 MW
- Fine tuning of fuel injection timing to balance Pmax values
- Endurance operation to confirm mechanical stability and performance
Results of the 12,000h Pielstick Engine Overhaul
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Full restoration of engine performance after 12,000 running hours
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Critical components returned to OEM specifications
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Improved reliability and operational stability
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Extended service life and reduced risk of unplanned failures
Engine delivered back to operation ready for continuous duty
INJEGOV Expertise in Pielstick Engine Overhauls
This project highlights INJEGOV’s proven capability in executing large-scale Pielstick engine overhauls, including:
- OEM-compliant overhaul procedures
- Advanced mechanical reconditioning
- Precision measurements and documentation
- In-depth expertise in medium-speed diesel engines
- Reliable execution within planned maintenance schedules
INJEGOV provides complete overhaul solutions for Pielstick engines used in power generation, marine, and industrial applications.
