MAIN ENGINE SULZER RTA 48
During dismantling the air sealing rings from the Main engine spare piston rod stuffing box for cleaning , nobody noticed how are these air sealing rings arranged .so after cleaning all the parts ,while assembling the air sealing rings were wrongly assembled.
Later when this piston was put in the unit with wrongly assembled stuffing box air sealing rings, as the scavenge pressure increased, crankcase was found pressurized and crankcase oil was found splashing out from the flywheel shaft seal.
Immediately Unit piston was changed with correctly overhauled stuffing box , found crankcase pressure normal.
Later on investigation we found out that the air sealing rings are to be overlapped with each other. It is written top on each part of air sealing ring ,the bottom part is to be overlapped with the other top part. Please see these photos for clear understanding.
The top part in photo shown is wrong assembly wereas the lower part shows the correct assembly , maintenance manual does not have any clear instructions So be careful and while dismantling the stuffing box for cleaning of sealing rings , senior engineers must be present and photos to be taken of every part dismantled, to enable correct reassemble.
Gud post
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