Explain the procedure of removal of liner in main engine (MAN B & W).

Here I have referred to a particular MAN B & W MC Engine. You should consult your manual also as surveyor mostly asks about the engine on your ship.

Precautions and procedures before removing liner:
  1. Inform company and take permission.
  2. Take immobilisation certificate from port state control.
  3. Read the manual and have a tool box meeting with everyone involved in the job. Discuss the complete procedure.
  4. Prepare important tools and spares required for overhauling liner as given in the manual.
  5. Prepare risk assessment and make sure all personal safety equipment are used
  6. Close the shut-off valves on the starting air receivers.
  7. Close all the shut-off valves in the control air supply unit and spring air and open the drain cocks in the two air receivers.
  8. Close by hand the automatic starting air shut-off valve and open the vent and drain valve to the main starting air piping on the engine as well as the vent valves on the automatic starting air shut-off valve, and leave them in this position until maintenance work is completed.
  9. Open all indicator cocks on the cylinder covers and leave them in this position until maintenance work is completed.
  10. Engage turning gear (gear pinion must be in engaged position) and lock the lever
  11. Stop main lube oil pump and switch off the breaker.
  12. Once the engine jacket temperature comes down, shut the inlet water valve for the unit to be overhauled.
  13. Keep other units in Jacket preheating system to maintain the jacket temperature
  14. Drain the jacket water of the concerned unit from exhaust v/v and liner.
  15. Remove jacket water connection.
  16. Shut the fuel oil to the particular unit whose liner is to be removed.
  17. Dismount the cylinder head using dedicated lifting tools.
  18. Remove the sealing ring from the top of the cylinder liner.
  19. Turn the piston down far enough to make it possible to grind away the wear ridges at the top of the liner with a hand grinder.
  20. Remove the piston together with piston gland.
Liner Removal procedure for MAN engine (MC engines)
  1. Disconnect at the non-return valve all the pipes leading from the cylinder lubricator to non- return valves.
  2. Check the condition of liner lifting tool and associated parts.
  3. Ensure the safety strap in the lifting hook is working properly.
  4. Tighten the two lifting tool screws in the liner as per the rated torque is given in the manual on both sides.
  5. Attach the crossbar to engine room crane. 
  6. Hook the chain from the lifting cross bar on the lifting screws and lift the cylinder liner with the cooling jacket out of the cylinder frame.


Fig.: Liner removal tool MAN B & W

Note: Never lift the cylinder liner with the crossbar attached to lifting screws in the cooling jacket

After Removing the liner from the engine:
  • Place the cylinder liner vertically on a wooden plank
  • Clean cylinder frame internally paying special attention to the contact surfaces for the cylinder liner at the top of the cylinder frame
  • Discard the O-ring on the cooling water pipe
  • Clean the pipe carefully

About the author

Anand Gautam

Anand Gautam is a marine engineer, Graduated from M.E.R.I. Mumbai. He likes to sail onboard ship and is one who is passionate about his job. He loves to share his knowledge, information, and ideas to everyone in a simplified way just for his satisfaction.

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