At RA Power Solutions, we have been carrying out crankshaft grinding repair for more than 47 years, supporting operators in the marine, power generation, mining, and heavy industrial sectors. Most of our work is completed directly at the customer's site using portable in-situ machining equipment, allowing crankshaft restoration without removing the engine from its foundation.
Over the years, we have completed more than 10,000 crankshaft grinding and repair assignments on two-stroke and four-stroke marine engines, diesel generators, compressors, turbines, and other rotating equipment. Every repair is performed within the manufacturer's specified tolerances, ensuring journal geometry, surface finish, and bearing clearances meet OEM requirements.
Insitu Crankshaft Grinding
Crankshaft grinding repair is a precision machining process used to restore damaged crankpins and main journals after wear, scoring, bearing failure, overheating, lubrication problems, or accidental damage. Instead of replacing the crankshaft, the damaged journal is machined to the next approved undersize while maintaining the required ovality, taper, fillet radius, and Ra surface finish specified by the engine manufacturer.
Where permitted by the OEM, the repaired journal is matched with the appropriate undersize bearing shells, allowing the engine to return to reliable service without replacing the complete crankshaft.
From our field experience, crankshaft grinding becomes necessary when inspection confirms that journal dimensions or surface condition exceed the manufacturer's allowable limits.
Typical reasons include the following:
Each crankshaft is inspected before machining to determine whether repair is technically acceptable within OEM regrind limits.
Most marine operators cannot afford the downtime involved in removing a crankshaft from the engine. In many cases, the repair is completed onboard while the vessel remains alongside or during scheduled maintenance.
Our standard process includes:
We inspect the damaged journals using precision measuring instruments to determine:
Every journal is measured to establish the machining allowance while confirming compliance with OEM regrind specifications.
Portable grinding equipment is mounted directly on the crankshaft. Material is removed gradually while continuously checking:
After grinding and polishing, final measurements are recorded and verified against the engine manufacturer's tolerances before the engine is reassembled.
Successful crankshaft grinding repair depends on maintaining critical journal geometry throughout the machining process.
We continuously monitor:
Maintaining these parameters is essential for proper hydrodynamic lubrication and long-term bearing performance.
Marine propulsion engines operate under continuous heavy loading, making journal accuracy essential for bearing reliability.
We regularly perform in-situ crankshaft grinding repair on the following:
When required, repairs are completed in accordance with inspection requirements from classification societies, including DNV, ABS, and Lloyd's Register.
Besides marine engines, we perform crankshaft grinding on equipment used in:
We also repair:
Our approach is based on practical field experience rather than workshop-only machining. Every repair is planned around the operating condition of the engine, available downtime, and OEM specifications.
Our experience includes:
Compared with crankshaft replacement, in-situ repair can offer significant operational advantages when technically feasible.
Benefits include:
RA Power Solutions provides crankshaft grinding repair services for the following:
With 47 years of experience and more than 10,000 successful repairs, RA Power Solutions provides in situ crankshaft grinding repair services worldwide for marine, industrial, and power generation applications. Every repair is performed with careful dimensional control to restore crankshaft journals within the manufacturer's specified tolerances while minimizing equipment downtime.
