RA Power Solutions was informed about the repeated failure of crankpin bearings of MAN B&W 5L 16/24 by one of our client base in Dubai.
We deputed our technicians to Duqm port in Oman to undertake the inspection of the crankshaft and repair. The crankpin diameter and other details are mentioned below.
S. No |
Crankshaft Details |
|
1 |
Engine Make |
MAN B&W |
2 |
Engine Model |
5L 16/24 |
3 |
Crank pin Diameter Standard |
130 mm |
4 |
Crankpin Bearing Width |
56 mm |
5 |
Place of execution of crankshaft repair |
Duqm Port, Oman |
Inspection undertaken by RA Power Solutions of Crankshaft of MAN B&W Engine Model no.5L 16/24
i) The connecting rods of all the five crankpins were removed.
ii) On visual inspection the crankpin bearings were observed damaged with line marks.
iii) All crankpins were checked dimensionally for taper & ovality and to our surprise the ovality ranging from 0.13 mm to 0.20 mm was observed. Considering the standard size of crankpin as 130 mm minus 0.03 mm, It is very much on the higher side. Copy of Inspection report of crankpin is pasted below.
iv) All the crankpins were subject to checking of hardness by portable hardness tester and it was observed within limits.
v) As a protocol the crankpins were also subject to crack detection test by MPI. No cracks or abnormality was observed.
vi) Bearing line marks and rough surface was observed on all crank pins journal.
Action taken by RA Power Solutions for successful repair of Crankshaft of MAN B&W Engine Model no. 5L 16/24
i) The five number crankpins were ground to the first step size of 0.5 mm maintaining the tolerances as per the manufacturer specifications.
ii) The final diameter was maintained between 129.47 mm and 129.50 mm.
iii) The radius and lubricating oil profile was maintained as per the original.
iv) Final readings of crankpins after grinding are pasted below.
Supply of undersize Bearing of MAN B&W Engine Model no. 5L 16/24
RA Power Solutions supplied 0.5 mm undersize bearings to the client.
The engine was commissioned in the presence of our technicians and performance was observed to be satisfactory.
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