Here I have referred to a particular Sulzer RTA Engine. You should consult your manual also as surveyor mostly asks about the engine on your ship.
Precautions and procedures before removing liner:
- Remove jacket water connection.
- Drain the jacket water of the concerned unit from exhaust v/v and liner.
- Keep other units in Jacket preheating system to maintain the jacket temperature
- Once the engine jacket temperature comes down, shut the inlet water valve for the unit to be overhauled
- Close the shut-off valves on the starting air receivers.
- Prepare risk assessment and make sure all personal safety equipment are used
- Prepare important tools and spares required for overhauling liner as given in the manual
- Read the manual and have a tool box meeting with everyone involved in the job. Discuss the complete procedure.
- Inform company and take permission.
- Take immobilisation certificate from port state control.
- 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.
- 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.
- Shut the fuel oil to the particular unit whose liner is to be removed.
- Dismount the cylinder head using dedicated lifting tools.
- Remove the sealing ring from the top of the cylinder liner.
- 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.
- Remove the piston together with piston gland.
Liner removal procedure of Main Engine (Sulzer RTA)
- Separate all piping connections for cylinder oil from the lubricating quills. All the passages for lubricating quills as well as their protecting bushes must be removed whenever a cylinder liner is being pulled out.
- The two screws fastening supporting ring with cylinder liner must be loosened and removed
- Mount suspension bridge beam with suspension straps loosely fitted.
Fig.: Liner removal tool for Sulzer
Note: The antipolishing ring if any, must be kept in the cylinder liner during lifting. It is needed for the guidance of the suspension bridge beam in the liner bore.
- Hand tighten (approx. 30 Nm) evenly the four screws until bottom of bore in the strap is in contact with the special screws (screw length inside the thread after the hand tightening minimum 1.2 of thread diameter).
- Hand tighten (approx. 30 Nm) the two screws
- Adjust the length of the four screws for the two suspension straps in such a way that the two special screws (suspension screws) can easily be screwed into the suspension holes provided on the cylinder liner .Note: Holes for suspension strap screws are at top of liner and special screws are at side of liner
- Pull cylinder liner fully out by the crane.