Importance of Repairing Connecting Rods

Connecting Rod Repair

The repair of connecting rod is of great importance to ensure the smooth and uninterrupted operation of the engine. It is observed that while the engine is continuously running the connecting rod big end bore develops taper and ovality or gets distorted similarly the small end of the connecting rod which generally has a gun metal or similar bush gets worn out of the certain hours of operation of the engine. It is advisable to conduct regular inspection of the connecting rod or at the time of undertaking major over hauling. Following is the process for inspection of the connecting rods. The connecting rods should be properly cleaned with a special attention to its serration. The connecting rod is subject to magnetic particle test for crack detection. It is generally observed that due to stress the hairline cracks are developed which are not desirable. The crack detection test can also be done by a simple die penetrant test. It is advisable to undertake the MPI and die penetrant test of connecting rods bolts and nuts as well.

The connecting rods bolts are tightened on a specified torque either manually or by hydraulic process. It is important that the torque is maintained strictly as specified in the manual.  The taper and the ovality are checked of big end bore. It is advisable to take as many readings as possible. The similar inspection is to be done for the small end bore as well.

In case of over sizing, taper and ovality it is recommended to either machine the serration on reduce the big end bore by doing the lapping of the serrations. Special purpose machines are available to undertake the lapping of the serration. The small end bush should be replaced in case of damage or excessive taper or ovality. It is recommended that the boring operation of big end and small end should be done on a boring machine which can maintain the tolerances as specified by the manufactures. Most of the cases for high capacity engines the maximum allowed taper and ovality is within 0.05mm.  The straightness of the connecting rods is of again real importance and this can also be checked on the boring machine before the correction of big end and small end bore.

All the connecting rods big end bores should either be replaced after certain hours of operation as mentioned in the manual or they should be checked periodically for its elongation. In case they are observed to be within the limits the bolts should be checked for the crack detection by MPI process. Any crack on the bolts is not permissible as it can results to the damaged to the connecting rods, engine block and other parts of the engine.

RA Power Solutions is undertaking re-sizing, repair and reconditioned of connecting rods for last more than 36years successfully. The connecting rods are repair strictly as per the specification and tolerances of the engine manufactures. Connecting rods after repair can also be subject to class approval in case required by the client. We can also supply reconditioned connecting rods of all make and models of the engine.