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A leading power plant based in Madagascar, East Africa, reported a failure of the crankshaft of a Wartsila 9L20 diesel generating set. They have multiple Wartsila DG sets of different models. They also operate Caterpillar engines.

Power plant officials were advised to open all the connecting rods and visually inspect the crankpins of the Wartsila 9L20. Damage to crankpin number #09 was reported. On going through the photographs of the damaged crankpin, the radius fillet on both sides of crankpin number #09 was observed to be damaged.

RA Power Solutions‘ two (2) technicians, along with an onsite crankshaft grinding machine, were deputed from our plant in New Delhi. The details of the engine and crankshaft are as follows:Action Taken by RA Power Solutions to Repair the Crankshaft of Wartsila 9L20 in Madagascar, East Africa

i) RA Power technicians followed a standard inspection protocol, during which the damaged crankpin number 9 was subjected to a dimensional check, crack detection by MPI, hardness check, etc. A pre-inspection report was prepared.

ii) On inspection of crankpin #09, excessive ovality of 0.41 mm was observed against the specified limit of 0.03 mm. The dimensional report is pasted below. Technicians also observed bearing line marks on the crankpin.

iii) RA Power Solutions carried out the repair by undersizing crankpin #09 of the Wartsila 9L20 by 1.00 mm, as the power plant had a 1.00 mm undersized bearing available. The engine was successfully commissioned in the presence of our technicians.

iv) The onsite crankshaft grinding machine, developed and manufactured by RA Power Solutions, is of the latest design and maintains a tolerance within 0.02 mm (20 microns) after grinding. The surface finish achieved is of a very high standard—15 RA value or less—which is highly recommended for ensuring the long life of bearings and crankshafts.
RA Power Solutions offers onsite crankshaft grinding and repair services under a wide range of conditions, whether on a ship at sea or at a power plant/cement plant in a remote location. All crankshaft grinding services provided by RA Power are guaranteed to ensure the satisfactory performance of the crankshaft and diesel engine after repairs.

RA Power Solutions is a well-known company that provides crankshaft repair, machining, and engine overhaul services on site to the marine, industrial, and power-generating sectors all over the world. The company has been in business for more than 45 years and has completed projects in Asia, Africa, Europe, the Middle East, and South America, bringing precision-engineered solutions right to clients’ premises. RA Power Solutions has powerful portable machining machines and a team of highly qualified experts. This means they can respond quickly, make repairs that are cost-effective, and do work that is as accurate as the original equipment manufacturer (OEM) anywhere in the world.

A leading power plant based in Madagascar, East Africa, reported a failure of the crankshaft of a Wartsila 9L20 diesel generating set. They have multiple Wartsila DG sets of different models. They also operate Caterpillar engines.

Power plant officials were advised to open all the connecting rods and visually inspect the crankpins of the Wartsila 9L20. Damage to crankpin number #09 was reported. On going through the photographs of the damaged crankpin, the radius fillet on both sides of crankpin number #09 was observed to be damaged.

Crankpin During Onsite Magnetic Particle Inspection TestWartsila 9L20 Engine Crankpin Inspection before Grinding

 

RA Power Solutions‘ two (2) technicians, along with an onsite crankshaft grinding machine, were deputed from our plant in New Delhi. The details of the engine and crankshaft are as follows:

Action Taken by RA Power Solutions to Repair the Crankshaft of Wartsila 9L20 in Madagascar, East Africa

i) RA Power technicians followed a standard inspection protocol, during which the damaged crankpin number 9 was subjected to a dimensional check, crack detection by MPI, hardness check, etc. A pre-inspection report was prepared.

ii) On inspection of crankpin #09, excessive ovality of 0.41 mm was observed against the specified limit of 0.03 mm. The dimensional report is pasted below. Technicians also observed bearing line marks on the crankpin.

Onsite crankshaft grinding of Wartsila 9L20 EngineWartsila 9L20 Engine MPI before crankpin grinding and polishing Wartsila 9L20 Engine crankshaft during grinding and machiningWartsila 9L20 Engine Crankpin under grinding repair

Metal Stitching, also called Cold Metal Repair or Metal Locking, uses precision mechanical techniques to restore cracked or damaged cast iron, cast steel, and aluminum components without welding or heat. Instead of melting the metal like welding does, this method uses specially designed keys and stitching pins (locks) to pull the cracked metal together and permanently seal the fracture.

This process is trusted in industries like,

• Marine engines and crankcases
• Power plants and turbine casings
• Pump and compressor housings
• Heavy industrial machinery

Why Not Welding?

Welding large cast components often causes:

• Heat distortion
• Loss of strength due to metallurgical changes
• Crack expansion or new cracks
• Metal stitching avoids heat damage and preserves the original material strength.

How Keys & Locks Work in Metal Stitching

The core of Metal stitching involves installing metal keys (locks) and stitching pins into the crack

Material Used in Metal Locking and Metal Stitching ProcessStep-by-Step Explanation:Step 1: Drilling and Stop-Holing

• Small holes are drilled at both ends of the crack.
• This prevents the crack from spreading during the repair.

Step 2: Installing “Locks” (Metal Keys)

• A series of overlapping slots are machined along the length of the crack.
• Technicians insert precision-engineered metal locks (keys) into the slots

Purpose of Keys/Locks:

• They mechanically pull both sides of the crack tightly together.
• They distribute load and stress evenly across the repaired area.
• The locks exceed the strength of the original casting and restore structural integrity

Step 3: Installing Stitching Pins

• Holes are drilled perpendicular to the crack.
• Technicians screw stitching pins into the holes to fill and seal the crack,

Purpose of Stitching Pins:

• They hold the metal in compression.

• They make the repair pressure-tight, preventing leaks of oil, coolant, or gas.

Step 4: Surface Finishing

• The repaired area machined flush.
• After finishing, the repair hides the crack and restores the component to OEM tolerances.

Metal Locking of Broken window

Advantages of Using Keys & Locks in Metal Stitching:

Where This Method Is Used

Metal stitching with keys and locks is commonly used for:

• Cracked diesel engine blocks
• Turbine and pump casings
• Compressor housings
• Marine engine frames and bedplates
• Generator casings

Whether the crack is small or several feet long, the stitching process scales to the size and location of the damage.

Metal stitching using precision metal keys and stitching locks is a reliable, proven, and cost-effective cold repair technique. Unlike welding, it involves zero heat—meaning no distortion, no stress, and no change in material properties. This method restores the structural integrity of cracked cast components and saves industries from huge downtime, dismantling, and replacement costs.

 

Product Details:

RA Power Solutions undertakes repair and rebabbitting of Wartsila engines and other makes of alternator and generator bearings. We have the facility to carry out rebabbitting for bearings up to 1500 mm in diameter.

Repair of Wartsila Generator Bearing

We received an old, damaged generator bearing from one of our clients based in Russia. The bearing had developed ovality, and the white metal was also chipped off. The rebabbitting of bearing was undertaken, and the final diameter was maintained as per the Wartsila alternator shaft.

Wartsila Generator Bearing Babbitt White Metal in Damaged ConditionWartsila Generator Bearing Babbitt White Metal During Inspection

The following are the main dimensions of the Wartsila Generator Bearing.

The following features have been adopted:

a) The white metal was removed from the bearings. A metallurgical test was done to determine the grade of the metal used.

b) We import and use only white metal from a leading manufacturer based in Spain.

c) After removal of the white metal, the bearing shell was subjected to sandblasting of the base metal surface to bare metal to create an acceptable coarse finish and attain excellent bonding with the Babbitt metal.

d) A magnetic particle test was done to check for cracks. It is our experience that cracks can develop in case of any accident or abnormal increase in temperature.

e) Hardness on the inner diameter of the bearing shall is checked. In case any hard spots are observed, they are removed by localized grinding or “scooping” technology.

f) The rebabbitting is done by a centrifugal system, which will ensure a uniform deposit of white metal with proper bonding.

g) Surfaces of the Babbitt is machined and polished to a mirror finish and applied with protective wax upon delivery.

h) After rebabbitting and machining, an ultrasonic test is done to check for any abnormalities.

Wartsila Generator Bearing After RepairWartsila Generator Bearing After Rebabbitting

Developing and manufacturing bearings as large as 1500 mm in diameter is no small feat. It speaks volumes about RA Power Solutions’ expertise in metallurgy, precision engineering, and quality control. These bearings are crucial for ensuring smooth operation and longevity in industrial machinery, where performance and reliability are paramount.

RA Power Solutions undertakes rebabbitting white-metal bearings for power plants, marine engines, and heavy industries in over 100+ countries. After 45 years, the business has perfected the entire rebabbitting process, from removing worn white metal to precise machining and final inspection. Before rebabbitting, bearings are stripped, metallurgically examined, sandblasted, and cracked and hard spot checked. Centrifugal casting ensures homogeneous bonding of premium imported Babbitt metal, followed by precise machining to client tolerances by RA Power Solutions. Ultrasonic and non-destructive testing verify each bearing’s mirror finish. One of the few firms globally that can handle large and crucial bearing jobs with guaranteed quality and fast turnaround, they can repair and produce bearings up to 1500 mm in diameter on-site or in-house.

A client operating a container vessel registered in Panama reported damage to the Daihatsu 6DK-20 engine. Our technicians boarded the vessel at Kolkata Port to assess the problem. The engine details are as follows:

 

 

On the visual inspection, the crankpin number #05 was observed to be damaged, and on the dimensional inspection, an ovality of 0.46 mm was observed. The readings are provided below:

 

After the pre-inspection of crankpin number 05 of the Daihatsu 6DK-20, as per the protocol, which included dimensional inspection, hardness testing, and Magnetic Particle Inspection (MPI) for crack detection, grinding was initiated, since all parameters were found to be within acceptable limits. The Crankpin Number #05 was undersized by 1.50 MM.

Supply Of Undersized Bearings For Daihatsu 6DK-20

Our technicians carried with them two (2) pairs each of 1.00 mm and 1.50 mm undersized crankpin bearings. The 1.50 mm bearings were fitted, and the engine was put back into operation within a few hours after the crankshaft repair of the Daihatsu 6DK-20 was executed. We maintain a large stock of crankpin bearings for the Daihatsu 6DK-20, as well as for other popular engine makes and models.

 

RA Power Solutions, with experience of more than 45 years, extends onsite crankshaft grinding services to leading shipping companies, power plants, and heavy industries all over the world.

We have a team of trained technicians available 24/7 and can be deputed on short notice. Some of our technicians also have valid US VISA and can fly to South America, Caribbean countries, etc.

In place crankshaft machining and grinding of the MAK-1 8CM32C engine was carried out in Burkina Faso, West Africa, by RA Power Solutions. RA Power Solutions has long been a leader in insitu crankshaft machining and grinding, specializing in the repair of both small and large diameter of crankpins and main journals. The company brings over 45 years of experience in this field.

We have developed a revolutionized tooling which has the capabilities to execute the repairs to close tolerances as stipulated in the engine manufacturer’s manual.

Case Study of Repair of MAK-1 8CM32C Engine Crankshaft In Burkina Faso, West Africa

The major details of the crankshaft of the MAK-1 8CM32C Engine are as follows:

i) Due to the repeated failure of bearings, it was decided by the client to get an audit of the crankshaft for all the major parameters. RA Power Solutions deputed two (2) technicians along with the onsite crankshaft grinding machine from New Delhi to Burkina Faso. During the initial inspection, the following was checked and observed.

In Place Machining of Crankshaft of MAK-1 8CM32C Engine

RA Power Solutions has been successfully executing the repair of high-diameter crankshafts up to 700 mm. We also specialize in onsite grinding of small-diameter crankpins with a bearing width of the crankpin as low as 50 mm to execute onsite such types of complex crankshaft repairs onsite. We have developed special-purpose onsite crankshaft machining equipment by which the repairs can be executed. We execute repairs for Marine, industrial, stationary power, and offshore sectors all over the world.

Our technicians are available to travel worldwide on short notice. Additionally, several of our technicians hold valid US visas, enabling them to travel to South America, the Caribbean, and other destinations as needed.

 

At RA Power Solutions, we provide specialized crankshaft grinding machines, onsite crankshaft grinding repair, insitu crankshaft grinding, Onsite crankshaft grinding machines,  insitu crankshaft grinding machines, crankpin bearings, metal stitching, metal locking, engine block repair, crack repair by metal stitching, cast iron crack repair, crankpin polishing, inspection of crankshaft, crankshaft inspection, rebabbitting bearing, babbitt white metal, engine overhauling, grinding of crankpin, connecting rod, and turbine shaft bearing services worldwide, including South Africa, Singapore, Greece, Dubai, Iraq, Iran, Malaysia, Colombia, and Brazil.