It is the experience of RA Power Solutions that in case of failure of connecting rod or main journal bearing, the surface finish of the crank pin or main journal of the crankshaft gets seriously damaged.
On crankshaft inspection after the accident, we have observed following
Observation of crankpin and main journal of crankshaft after bearing failure
- Due to failure of crank pin or main journal bearings, on visual inspection the crankpin and main journal diameter develops line marks, pitting, and rough surface.
- In case after failure of crank pin, the main journal bearing, the engine is not stopped on time, and the radius fillet of both sides gets damaged. In some cases, we have noticed that the lubricating oil hole profile also gets lost.
- In most of cases, bearing failure results in the sticking of bearing material on the crankshaft surface. The main reason is that the bearing steel shell rubs with the crankpin and main journal diameter, temperature abnormally increases due to friction, and bearing material melts.
- Overheating due to failure of bearing shell on the crankshaft also results in black/ blue discoloration.
- The hardness increases due to abnormal heating.
- Cracks on crank pin and main journal in some of the cases are also observed.
- In case the accident is serious, it can also cause the loss of alignment of the crankshaft which becomes a serious issue for onsite repair.
- In case of above observation, certainly it is not possible to assemble the new bearings and operate the engine.
- The crankpin and main journal of the crankshaft after thorough examination requires grinding.
- We have observed that in some cases ship owners and maintenance engineers try to do the polishing of crankpin and main journal by hand which results in the repetitive failure of bearing and crankshaft.
- As a repair company with forty years of experience, we have observed that generally the crank pin and main journal diameter has to be maintained between 0.03 and 0.05 mm which is impossible to maintain by hand.
- Hence, RA Power Solutions does not recommend polishing the crankshaft by hand.
Specialization of RA Power Solutions in Crankshaft Machining and Polishing on Site
RA Power Solutions specializes in repair of crankshaft onsite without removing it from the engine block. Our technicians with onsite portable crankshaft machining equipment visit your plant or board the vessel all over the world to undertake the repairs.
With more than 10, 000 crankshaft repair jobs undertaken by us, our success rate of repair of seriously damaged crankshaft is almost 100%. We agree that there are cases where due to failure of bearing, generation of abnormal heat, multiple cracks are developed or the taper and ovality developed after the accident are higher than the last limits specified by the manufacturer. In that case there is no point in attending to the repairs.
Following steps are taken for successful repair of crankshafts of main and auxiliary engines
We give great importance to the pre-inspection of the damaged crankshaft. This is done by our experienced technicians using the state of art measuring instruments which are calibrated and certified by the agency of repute.
Pre-inspection includes the following
- Dimensional inspection of crankpin and main journal.
- Checking deflection/run-out to know the loss of alignment of crankshaft if any.
- Checking of hardness.
- Crack detection by MPI, Dye–penetrant test.
- Visual inspection
- The pre-inspection report of crankshaft is thoroughly studied by our technicians on site and strategy and successful repair is planned.
- The grinding of crankpin and main journal is undertaken removing the minimum stock possible. This helps in enhancing the life of the crankshaft.
- The removal of minimum stock from crank pin and main journal is possible only because of the use of the latest generation of onsite crankshaft grinding machine by us.
- The final inspection is undertaken and reports are prepared.
RA Power Solutions regularly undertake on site grinding of crankshaft, rotating shafts, alternator shafts, rotor shafts, turbine shafts, electric motor shafts, crankshaft machining and polishing.
We provide crankshaft grinding services in countries like Australia, Bangladesh, Cambodia, Chinese Mainland, Hong Kong, Indonesia, Japan, Malaysia, Maldives, Myanmar, New Caledonia, New Zealand, Philippines, Singapore, South Korea, Sri Lanka, Thailand, Vietnam, Afghanistan, Bahrain, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, United Arab Emirates, Yemen, etc.
For more information, in place crankshaft machining and polishing, polishing crankshaft please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.
