Ensuring Engine Integrity Through Precision Measurement
Cylinder Condition Monitoring (CCM) & Liner Diameter Measurement (LDM)
At Green Shift Group, we provide comprehensive Cylinder Condition Monitoring (CCM) and Liner Diameter Measurement (LDM) services for large two-stroke marine diesel engines such as MAN B&W and Wärtsilä.
These inspections are essential for maintaining engine performance, reducing wear-related failures, and ensuring compliance with OEM and class requirements.
What is LDM?
Liner Diameter Measurement (LDM) is the systematic measurement of the internal diameter of a cylinder liner at multiple heights and angles.
It provides valuable insight into the liner’s wear condition and helps detect:
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Cylinder wear and ovality
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Scuffing or polishing
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Abnormal or uneven wear patterns
Measurements are typically performed using precision micrometers or OEM-approved liner measurement tools.
Where and How It’s Done
LDM is performed through the scavenge ports when the piston is positioned at Top Dead Center (TDC) or Bottom Dead Center (BDC).
Measurements are taken at different liner levels:
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Top dead center (just below piston ring reversal area)
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Mid-stroke
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Bottom dead center​
At each level, readings are taken in at least two directions (athwartship and fore-aft ) to accurately determine wear and out-of-roundness.
Why It Matters
Accurate liner measurements are key to predictive maintenance. Regular LDM inspections help to:
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Verify that liner wear remains within manufacturer limits
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Plan timely re-lining, honing, or overhauling
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Prevent compression loss, blow-by, and scuffing
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Reduce lube oil consumption and operational costs
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Support class condition monitoring programs (CCM)
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Leading OEMs such as MAN B&W and Wärtsilä also integrate LDM into their digital condition monitoring systems, enabling long-term trend tracking and performance optimization.
Cylinder Condition Monitoring (CCM) – Scope of Work
Our CCM service package provides a complete overview of cylinder and liner condition onboard.
Scope includes:
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Liner Diameter Measurement (LDM)
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Piston ring coating measurement
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Piston ring pack and top land photography
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Replica collection and microscopic analysis (for Cat fines and surface wear)
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Cylinder liner wall photography
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Comprehensive summary report with findings and recommendations
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Online presentation of results via Teams with vessel or office personnel.
Service Details (Example)
Estimated Duration: around 1 full day onboard
Example Engine: MAN 5S50MC
Port / Vessel / IMO / Date: To be advised
Pricing: On request
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To ensure smooth execution, please prepare the following before attendance:
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Open charge air covers
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Remove starting air valves for liner access
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Prepare the engine turning gear
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Cool the engine to below 65 °C
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Clean the piston crown and liner area
Deliverables
Upon completion, you will receive:
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A detailed CCM report with liner wear data, replica microscopy images, and recommendations
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Trend charts comparing previous data (if available)
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Follow-up consultation with our engineers to interpret results and optimize maintenance planning
