Stuffing box



  • Provides sealing between Scavenge space and Crankcase
  • Upper section prevents scavenge air & residues from scavenge space entering crankcase
  • Lower section prevents oil carry over by piston rod from crank case to scavenge space
  • Middle or neutral section provides drain from any leakage from the upper of lower section.

  • Stuffing box is bolted to diaphragm through which piston rod passes.
  • It is held in the casing which can be vertically split
  • Rings are each made up of 3-4 segments & each segments are held together with garter spring.
  • Rings are either bronze or steel backing which consists of replaceable cast iron lamellas.


  • Housing: Cast Iron or Cast Steel
  • Rings: bronze or steel or PTTF being introduced newly
  • Lamellas:  cast iron or carbon.

Examining the stuff box

Observing the open ended Tell tale we can ascertain the quality of rings

If large quantity of oil then lower scrapper rings are worn out or faulty

If  air is blowing out then upper set of rings are worn out or faulty.

Maintenance required

Spring length to be checked for elongation and loss of tension and strength

ring butt and axial clearances

Cross head guide clearances are more that results in wearing of stuffing box Rings.