Precautions and procedures before removing cylinder head:
- Inform company and take permission.
- Take immobilisation certificate from port state control.
- Read the manual and have a tool box meeting with everyone involved in the job. Discuss the complete procedure.
- Prepare important tools and spares required for overhauling liner as given in the manual
- Prepare risk assessment and make sure all personal safety equipment are used
- 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.
- 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.
- Open all indicator cocks on the cylinder covers and leave them in this position until maintenance work is completed.
- Engage turning gear (gear pinion must be in engaged position) and lock the lever
- Stop main lube oil pump and switch off the breaker. Put the tag ‘Man at Work’
- Once the engine jacket temperature comes down, shut the inlet water valve for the unit to be overhauled.
- Keep other units in Jacket preheating system to maintain the jacket temperature.
- Drain the jacket water of the concerned unit.
- Remove jacket water connection.
- Remove high pressure hydraulic pipe connection to the exhaust valve.
- Shut the fuel oil to the particular unit whose liner is to be removed.
- Dismount high pressure fuel pipes to the cylinder.
- Remove exhaust bellow.
FIG.: Removal of cylinder head
Removal of cylinder head:
- Remove the hydraulic jacks, spacer rings and nuts.
- Release the pressure.
- 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
- Pull down the hydraulic jacks of the tightening tool and screw the jacks on to the stud.
- Position the cylinder cover tightening tool over the cylinder cover.
- Place the spacer rings over the cylinder head nut.
- Hook the engine room crane on to the lifting attachment on the top of exhaust valve.
- Lift away the cylinder cover completely and land it, on a couple of wooden planks.
- Remove and discard the sealing ring between cylinder cover and liner