Removing a crankshaft from a vessel is a time-consuming operation requiring extensive dismantling, dry docking, heavy lifting equipment, and prolonged vessel downtime. Modern on site crankshaft repair and reconditioning techniques allow damaged journals to be restored directly inside the engine block while maintaining OEM tolerances and class requirements.

Initial Inspection Before In Situ Crankshaft Grinding

Every successful repair begins with a detailed inspection. Before any machining operation is started, the crankshaft condition must be thoroughly evaluated to determine whether repair is technically feasible.
The inspection process includes:

• Visual inspection of crankpins and main journals
• Measurement of journal diameter
• Ovality and taper measurement
• Run-out and crankshaft alignment inspection
• Surface roughness evaluation
• Oil hole inspection
• Bearing contact pattern examination
• Lubrication failure analysis
• Fillet radius inspection
• Assessment of previous repairs

Only after these measurements are completed can the appropriate repair procedure be selected.

Crankshaft Crack Inspection and Grinding

One of the most critical stages of crankshaft restoration is crankshaft crack inspection and grinding.
Before commencing grinding operations, every crankpin and main journal is inspected using approved Non-Destructive Testing (NDT) methods, including:

• Magnetic Particle Inspection (MPI)
• Dye Penetrant Testing (DPT)
• Ultrasonic testing where applicable

Particular attention is given to:

• Fillet radius
• Oil holes
• Journal edges
• Stress concentration areas
• Previous repair locations

If cracks are detected beyond OEM permissible limits, grinding alone cannot restore the crankshaft, and further engineering evaluation is required. When no structural defects are present, controlled grinding can proceed safely.

In Situ Grinding of Crankpin

The most common repair carried out onboard is in situ grinding of the crankpin.
After removing the damaged bearing shells and preparing the journal surface, specially designed orbital grinding equipment is mounted directly around the crankpin. The equipment rotates concentrically with the crankshaft while maintaining precise dimensional control throughout the grinding cycle.

During grinding, continuous measurements are taken to monitor:

• Journal diameter
• Cylindricity
• Taper
• Ovality
• Surface finish
• Fillet radius

Grinding is performed gradually to avoid thermal distortion while ensuring the finished journal remains within the manufacturer’s regrinding limits.

Crankshaft Grinding Main Journal

When excessive wear or scoring is observed on the main bearings, Crankshaft Grinding Main Journal becomes necessary.
Unlike crankpin repair, main journal grinding requires additional alignment verification because the main journals directly influence crankshaft geometry and engine bearing loads.
Throughout the machining process, engineers continuously verify:

• Main bearing alignment
• Journal concentricity
• Bearing housing condition
• Lubrication passages
• Surface finish

Proper restoration of the main journals ensures stable hydrodynamic lubrication and long bearing life after reassembly.

In Situ Crankshaft Machining

Modern in situ crankshaft machining allows highly accurate restoration of damaged journals without removing the crankshaft from the vessel.
The machining equipment is rigidly mounted around the crankshaft and incorporates precision feed mechanisms capable of producing controlled material removal while maintaining excellent dimensional accuracy.
Typical machining operations include:

• Journal reconditioning
• Radius correction
• Surface restoration
• Undersize machining
• Finish grinding
• Precision polishing

This method significantly reduces repair duration compared to conventional workshop repairs.

Inplace Crankshaft Machining

Inplace Crankshaft Machining eliminates the need for transporting the crankshaft to an external machine shop.
The complete repair is performed onboard, reducing:

• Dry dock requirements
• Heavy lifting operations
• Engine dismantling
• Transportation risks
• Vessel downtime
• Repair costs

This approach has become the preferred solution for many commercial vessels operating under tight schedules.

Grinding of Crankshaft Onsite

Professional grinding of the crankshaft onsite follows a carefully controlled engineering procedure.
The repair sequence generally includes:

• Initial inspection
• Dimensional measurement
• Crack inspection
• Bearing removal
• Machine installation
• Alignment verification
• Controlled grinding
• Radius finishing
• Journal polishing
• Dimensional inspection
• Surface finish verification
• Final documentation

Each stage is recorded to maintain complete traceability for vessel records and classification society requirements.

Crankshaft Grinding Onsite

Successful Crankshaft Grinding Onsite depends on precision rather than speed.
Throughout the repair, engineers continuously monitor:

• Journal temperature
• Grinding pressure
• Material removal rate
• Surface finish (Ra value)
• Journal geometry
• Oil clearance
• Bearing seating

The objective is to restore the crankshaft to OEM specifications while ensuring reliable engine operation after commissioning.

Onsite Journal Machining Services

Professional Onsite Journal Machining Services cover both crankpins and main journals across a wide range of marine engines.
These services typically include:

• Journal measurement
• Precision grinding
• Radius restoration
• Journal machining
• Journal polishing
• Bearing seating correction
• Dimensional verification
• Final inspection

Accurate journal geometry is essential for maintaining proper oil film thickness and preventing premature bearing failures.

In Situ Crankshaft Polishing

Following grinding operations, In Situ Crankshaft Polishing is carried out to achieve the specified surface finish.
Controlled polishing removes microscopic grinding marks while improving the journal’s ability to support a stable hydrodynamic oil film.

Final polishing also:

• Reduces friction
• Improves bearing bedding
• Minimizes wear
• Enhances lubrication performance
• Extends crankshaft service life

The finished journal is verified for surface roughness before final acceptance.

Crankshaft Grinding Repair Services on Vessel

Modern crankshaft grinding repair services on vessels enable repairs to be completed while the engine remains installed onboard.
This approach offers several operational advantages:

• Minimal engine dismantling
• No crankshaft removal
• Reduced downtime
• Lower repair costs
• Faster return to service
• Compliance with OEM repair procedures
• Support during voyage or port stay, subject to operational conditions

These services are routinely performed on propulsion engines, auxiliary engines, generator engines, and compressor drive engines across various vessel types.

Vessel Crankshaft Repair

Every Vessel Crankshaft Repair project concludes with a comprehensive quality inspection before the engine is returned to operation.
The final inspection includes:

• Journal diameter verification
• Ovality confirmation
• Taper measurement
• Fillet radius inspection
• Surface finish measurement
• Bearing clearance verification
• Oil hole cleaning
• Crankshaft rotation check
• Final NDT where required
• Sea trial or operational testing

Only after all parameters comply with OEM recommendations is the repair considered complete.

RA Power Solutions has successfully repaired crankshafts of MAN B&W, Wärtsilä, Sulzer, MAK, Caterpillar, Daihatsu, Yanmar, Deutz, Pielstick, Himsen, Allen, Ruston, ABC, Bergen, Niigata, EMD, Cummins, and many other marine and generator engine models. Our in situ crankshaft grinding and repair services have been delivered in over 100 countries, serving ship owners, power plants, offshore operators, and industrial facilities worldwide.

We also specialize in the inspection, repair, rebabbitting, and manufacturing of main bearings, crankpin bearings, connecting rod bearings, thrust bearings, white metal (Babbitt) bearings and engine bearing bushes, providing complete rotating equipment and engine repair solutions from a single source.

For more information on onsite crankshaft repair, grinding of crankshaft, and crankshaft polishing please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

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The white metal (Babbitt) bearings used in Wärtsilä alternator (generator) bearings are designed for continuous operation under heavy loads, vibration, high temperatures, and dusty conditions. It is important that the rebabbitting of old Wärtsilä alternator (generator) bearings is carried out to high standards to ensure satisfactory performance and a long service life.

Repair Process Of Wärtsilä Alternator (Generator) Bearings

At RA Power Solutions, every Wärtsilä alternator (generator) bearing undergoes a comprehensive inspection before the repair process begins. The bearing shell is thoroughly cleaned, inspected, and prepared prior to the application of new Babbitt white metal.

Our repair process includes:

• Complete removal of damaged Babbitt white metal.
• Thorough cleaning and preparation of the bearing shell.
• Controlled tinning process for superior metallurgical bonding.
• Centrifugal or gravity casting of premium-grade Babbitt white metal.
• Precision machining to OEM dimensions.
• Final inspection and testing before dispatch.

Why RA Power Solutions Leads in Wärtsilä Alternator (Generator) Bearing Repair

i) Bearing Material Used for the Repair of Wärtsilä Alternator (Generator) Bearings

• RA Power uses a higher grade of Babbitt white metal ingots than those originally used in Wärtsilä alternator (generator) bearings. This results in a considerably longer bearing life.
• The Babbitt metal used has excellent resistance to fatigue.
• Helps prevent bearing seizure.

The use of high-quality Babbitt significantly increases bearing reliability under continuous operating conditions.

ii) Bonding Quality of Babbitt White Metal in Wärtsilä Alternator (Generator) Bearings

• RA Power ensures a strong metallurgical bond between the Babbitt white metal and the steel shell.
• No cracks, porosity, or delamination are accepted.
• Ultrasonic and dye penetrant tests are carried out. (These inspections ensure complete bond integrity before machining.)

iii) Maintenance of Surface Finish

A properly finished bearing surface is essential for stable oil film formation and low operating temperatures.

• Our machining standards include:
  • Precision-machined bore.
  • Surface roughness typically between Ra 0.2–0.4 µm.
  • Accurate scraping where required.
  • Optimum surface finish for hydrodynamic lubrication.

The result is smooth shaft rotation with minimal friction and wear.

iv) Lubrication Features

Proper lubrication is essential for the reliable operation and long service life of Wärtsilä alternator (generator) bearings. During the repair process, RA Power Solutions ensures that all lubrication features are restored to the original specifications, including:

• Correctly designed oil grooves for uniform oil distribution.
• Properly positioned oil inlet and outlet locations.
• Chamfered oil holes to prevent disruption of the oil film.
• Adequate oil wedge formation for effective hydrodynamic lubrication.

These features ensure continuous lubrication under varying operating loads.

v) Precision Bearing Geometry

Accurate bearing geometry is critical for smooth operation and optimum load distribution. Every repaired bearing is precision-machined and inspected to ensure:

• Accurate internal diameter.
• Correct bearing clearance as specified by Wärtsilä.
• Proper bearing crush and housing fit.
• Correct roundness and alignment.

Dimensional accuracy is verified using calibrated precision measuring instruments.

vi) High Load-Carrying Capacity

Repaired Wärtsilä alternator bearings are capable of handling demanding operating conditions, including:

• Continuous radial loads.
• Dynamic loading.
• Sudden electrical load fluctuations.
• Rotor imbalance.
• Thermal expansion during operation.
• Continuous heavy-duty service.

The combination of premium Babbitt material and precision machining ensures exceptional load-carrying capability.

vii) Inspection Features

To facilitate easy maintenance and condition monitoring, the repaired bearings retain all essential inspection features, including:

• Provision for temperature monitoring (RTD/PT100 sensors).
• Vibration monitoring.
• Oil sampling.
• Visual inspection during routine maintenance.

These features enable operators to monitor bearing health throughout its service life. Our objective is not merely to repair bearings but to enhance their reliability, operational efficiency, and service life.

Importance of Wärtsilä Alternator (Generator) Bearing Rebabbitting

Wärtsilä alternator (generator) bearings operate under continuous load, high temperatures, and vibration. Wear of the Babbitt white metal, excessive bearing clearance, or surface damage can affect rotor stability, lubrication, and bearing performance. Rebabbitting at the right stage restores the bearing to OEM specifications and prevents further damage to the journal and rotor.

Why RA Power Solutions?

With over 47 years of experience, RA Power Solutions specializes in Wärtsilä alternator (generator) bearing rebabbitting and repair using proven engineering practices.

• Premium-grade Babbitt white metal
• Superior metallurgical bonding
• Precision machining to OEM dimensions and clearances
• Inspection of bond quality, bearing geometry, and surface finish
• Cost-effective repair compared to new bearing replacement
• Fast turnaround with guaranteed workmanship

Engineering Support for Wärtsilä Alternator (Generator) Bearings

If your Wärtsilä alternator (generator) bearing shows signs of white metal damage, overheating, scoring, fatigue, or excessive wear, our engineering team can inspect, rebabbitt, machine, and restore the bearing to OEM standards.

Contact RA Power Solutions

For more information about Wärtsilä alternator (generator) bearing rebabbitting and repair, contact RA Power Solutions Pvt. Ltd.

Email: rajshahani@rapowersolutions.com | info@rapowersolutions.com

Phone: +91 9582647131 | +91 9810012383

Our engineering team will be pleased to assist you with technical guidance, bearing inspection, bearing repair solutions, and quotations for Wärtsilä alternator (generator) bearings.

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The MAN 7L23/30H engine crankshaft of a vessel at Khor Al Zubair Port, Iraq, was reported damaged. RA Power Solutions has repaired a number of crankshafts of MAN 7L23/30H engines during the last 46 years of extending services all over the world. With our experience and based on the initial reports of damage shared by the vessel, we planned the strategy for the repair of the MAN 7L23/30H engine at Khor Al Zubair Port, Iraq.

The tooling was prepared, and two technicians having a valid seaman’s book flew to Khor Al Zubair Port, Iraq, with an onsite crankshaft grinding machine. The technicians also carried undersized crankpin bearings with them in order to facilitate the immediate commissioning of the engine after the necessary repairs were executed.

Damaged Crankpin Journal of MAN 7L23/30H Auxiliary Engine

Damaged Crankpin of MAN 7L23/30H Auxiliary Engine

Engine Details of the MAN 7L23/30H

Crankshaft Inspection by MPI – MAN 7L23/30H Auxiliary Engine

Crack Detection Using MPI – MAN 7L23/30H Auxiliary Engine

Observation and Repair of the Crankshaft of MAN 7L23/30H at Khor Al Zubair Port, Iraq

i) On visual inspection, two crankpins, Nos. 4 and 6, were observed to be damaged. Crankpin bearing material was found in the oil sump of the entablature.
ii) Crankpins Nos. 4 and 6 were inspected for taper and ovality, and the following readings were observed.

iii) Other parameters, such as hardness and crack detection tests by MPI, were carried out, and no abnormalities were observed.

iv) It was jointly decided, in consultation with the owners, to undertake the grinding in steps of 0.5 mm onwards, as per the manufacturer’s guidelines.

v) After the grinding operation, both crankpins No. 4 and No. 6 were undersized by 1.50 mm, and all parameters were maintained as per the manufacturer’s specifications and recommendations.

Onsite crankshaft machining in process for MAN 7L23/30H Auxiliary Engine

Final Dimensions After Repair

Availability of Undersized Bearings for MAN 7L23/30H

RA Power Solutions technicians carried the undersized crankpin bearings to Khor Al Zubair Port, Iraq, and the engine was assembled and commissioned in their presence. RA Power Solutions maintains undersized bearings for popular engine makes to facilitate clients.
For all repairs, including the above crankshaft of MAN 7L23/30H, we provide records of the inspection report before and after the repair of the crankshaft. These reports are signed and stamped by the Chief Engineer of the vessel. On request, we can share these reports with our clients.

This case once again highlights RA Power Solutions’ proven capability to execute critical crankshaft repairs worldwide with high precision, strong technical expertise, and extensive field experience, ensuring reliable and timely solutions for marine and industrial engines.

For more information on onsite crankshaft repair, grinding of crankshaft, and crankshaft polishing, please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

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The details of the DEUTZ SBV 12M 628 are as follows: –

Crankpin Wear and Scoring Marks on Crankshaft of DUETZ SBV 12M 628 Engine	Damaged Crankpin of DUETZ SBV 12M 628 Engine

MPI Testing on Crankpin of DUETZ SBV 12M 628 Engine	Crankshaft Inspection by MPI – DUETZ SBV 12M 628

Inspection and Repair of DEUTZ SBV 12M 628

After inspection of all the crankpins, it was decided to grind crankpin numbers 02 and 04, and balance crankpin numbers 01, 03, 05, and 06, which were polished.

The following final dimensions were maintained:

The undersized bearings have been arranged by the client, and the engine has been commissioned.

Smooth Crankpin Finish After Grinding and Polishing – DUETZ SBV 12M 628	Final Surface Finish of DUETZ SBV 12M 628 Crankshaft

The above repair work on the DEUTZ SBV 12M 628 crankshaft was carried out successfully without removing the crankshaft from the engine. Precision grinding and polishing ensured that all crankpins were brought within acceptable limits with minimum ovality and proper surface finish. Following assembly with undersized bearings supplied by the client, the engine was commissioned successfully and is running satisfactorily.

For more information on onsite crankshaft repair, grinding of crankshaft, and crankshaft polishing, please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

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The major crankshaft details of the Daihatsu 6DKM-36 are as follows:

Damaged Crankpin of Daihatsu 6DKM-36 Engine	Crankpin Wear and Scoring Marks on Crankshaft of Daihatsu 6DKM-36 Engine
MPI Testing on Crankpin of Daihatsu 6DKM-36 Engine	Non-Destructive MPI Testing of Crankpin – Daihatsu 6DKM-36 Engine

Observation of The Crankshaft of Daihatsu 6DKM-36

i) On visual inspection, it was noted that the bearing of crankpin number 03 was damaged, and bearing material was accumulated in the sump.

ii) On opening the connecting rod, the bearing was found to be badly damaged. Crankpin number 03 was also embedded with bearing material.

iii) The bearing material was removed, and crankpin number 03 was inspected for dimensions (taper & ovality).

The following minimum and maximum dimensions were noted:

iv) Due to high temperature and rubbing of the bearing on the crankpin, multiple scoring marks were observed.

Action Taken by RA Power Solutions for the Successful Repair of Daihatsu 6DKM-36 Crankshaft

The grinding of crankpin number 03 was started with an onsite crankshaft grinding machine. Initially, considering the ovality, it was estimated that the crankpin was to be undersized by 0.5 mm. However, on evaluation, it was decided to reduce the diameter of the crankpin further by 0.5 mm. The undersize of 1.00 mm was maintained.

The readings observed after grinding are pasted below:-

The ovality was maintained within 0.02 mm.

Smooth Crankpin Finish After Grinding and Polishing – Daihatsu 6DKM-36	Crankshaft Grinding and Repair of Daihatsu 6DKM-36 Engine

RA Power Solutions has been extending crankshaft repair services all over the world for 47 years of experience. We have successfully repaired and saved ten thousand (10000) crankshafts from rejection by using our experience. A few crankshafts have been repaired by us under deviation with the presence of cracks or undersizing beyond the last limit prescribed by the manufacturer.

For all repairs, including the above crankshaft of Daihatsu 6DKM-36, we provide records of the inspection report before and after the repair of the crankshaft. These reports are signed and stamped by the Chief Engineer of the vessel. On request, we can share these reports with our clients.

This case once again demonstrates RA Power Solutions’ capability to undertake critical crankshaft repairs worldwide with high accuracy, technical expertise, and proven field experience.

For more information on onsite crankshaft repair, grinding of crankshaft, and crankshaft polishing, please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

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The Rolls-Royce (Bergen B32:40L8P) is installed on a vessel as the main engine. The vessel was at the outer anchorage of Mumbai Port.

The details of the crankshaft and engine are as follows:

Our two (2) technicians with onsite crankshaft grinding machine and measuring equipment boarded the vessel at short notice. A detailed inspection was undertaken, and crankpin number #06 was found damaged.

The main observations of crankpin number #06 of Rolls-Royce (Bergen B32:40L8P) are as follows:

i) Minimum Diameter of Crankpin Number #06 – 268.57 MM
ii) Maximum Diameter of Crankpin Number #06 – 270.00 MM
Ovality—1.43 MM

In the MPI test, hairline cracks were also observed. RA Power Solutions technicians executed the repairs by grinding the crankpin number #06 undersized by 2.00 mm. The bearing was available onboard the vessel, and the engine was commissioned in a very short time.

RA Power Solutions offers on-site crankshaft grinding and repair services under a wide range of conditions, whether on a vessel at sea or at a power plant/cement plant in a remote location. All crankshaft grinding services provided by RA Power Solutions are guaranteed to ensure the crankshaft and diesel engine perform satisfactorily after repairs.

RA Power Solutions has always committed itself to delivering excellent and timely service. With over 47 years of experience, we have successfully repaired more than 10,000 crankshafts worldwide.

Crankpin Bearings In Stock For Rolls-Royce Bergen B32:40L8P Engine

RA Power Solutions has a ready stock of crankpin bearings for the Rolls-Royce Bergen B32:40L8P engine to meet urgent replacement requirements during on-site crankshaft repair and grinding. Standard and undersized crankpin bearings are available for immediate dispatch to assist vessel owners and operators in minimising downtime and getting the engine back to full power as soon as possible. Our crankshaft grinding expertise, combined with authentic crankpin bearings, means faster repair execution and complete compliance with OEM specifications after crankshaft restoration.

For more information on onsite crankshaft repair, crankshaft grinding, and crankshaft polishing, please email us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

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