Explain the procedure of removal of cylinder head of main engine

Precautions and procedures before removing cylinder head:

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. Close all the shut-off valves in the control air supply and safety air unit and open the drain cocks in the two air receivers.
7. 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.
8. Open all indicator cocks on the cylinder covers and leave them in this position until maintenance work is completed.
9. Engage turning gear (gear pinion must be in engaged position) and lock the lever
10. Stop main lube oil pump and switch off the breaker.  Put the tag ‘Man at Work’
11. Once the engine jacket temperature comes down, shut the inlet water valve for the unit to be overhauled.
12. Keep other units in Jacket preheating system to maintain the jacket temperature.
13. Drain the jacket water of the concerned unit.
14. Remove jacket water connection.
15. Remove high pressure hydraulic pipe connection to the exhaust valve.
16. Shut the fuel oil to the particular unit whose liner is to be removed.
17. Dismount high pressure fuel pipes to the cylinder.
18. Remove exhaust bellow.

FIG.: Removal of cylinder head

Removal of cylinder head:

1. Remove the hydraulic jacks, spacer rings and nuts.
2. Release the pressure.
3. Connect the hydraulic hoses to the jacks and raise the pressure as stated in the manual(1000 bar). Loosen the nuts with a tommy bar
4. Pull down the hydraulic jacks of the tightening tool and screw the jacks on to the stud.
5. Position the cylinder cover tightening tool over the cylinder cover.
6. Place the spacer rings over the cylinder head nut.
7. Hook the engine room crane on to the lifting attachment on the top of exhaust valve.
8. Lift away the cylinder cover completely and land it, on a couple of wooden planks.
9. Remove and discard the sealing ring between cylinder cover and liner