SL2016-635/JNN Fretting Marks on Connecting Rod Contact Surfaces

This service letter contains important information about the development of fretting marks at the assembly surfaces of the connecting rod and the marine head, and possible rework of this. The complete connecting rod consists of three different parts, upper and lower marine head parts and the connecting rod. Due to the operation forces the connections of these parts are exposed to the development of fretting that may occur over time.

This service letter contains important information about the development of fretting marks at the assembly surfaces of the connecting rod and the marine head, and possible rework of this.

The complete connecting rod consists of three different parts, upper and lower marine head parts and the connecting rod. Due to the operation forces the connections of these parts are exposed to the development of fretting that may occur over time.
Fretting marks are caused by micro movements between two parts under high load.

Owners and operators of
MAN four-stroke diesel engines.
Types:
Propulsion: L21/31, L27/38
GenSet: L21/31, L21/31S, L27/38, L 27/ 3 8 S
Reference Work cards 5 0 6 - 01.15   a n d M116110 - 01