Saturday, June 27, 2020

Procedure for opening Main Engine Liner

Following Procedure has to be followed when opening Liner
  • 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
  • Shut starting air for Main Engine and display placards
  • Engage turning gear
  • Open indicator cocks for all the cylinders
  • Stop main lube oil pump and switch off the breaker
  • 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 from exhaust v/v and liner.
  • Shut the fuel oil to the particular unit whose liner is to be removed
  • Dismount the cylinder head using dedicated lifting tools
  • Discard 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
  • Dismount the piston by following the procedure given in Manual
Liner Removal procedure for MAN engine (MC and ME engines)
Ensure the Liner lifting tool is well maintained. Two lifting screws are used with a lifting hook connected via chain. Ensure chain, screw and lifting hook are fastened together with no deformation
  • Ensure the safety strap in the lifting hook is working properly.
  • Tighten the two lifting tool screws in the liner as per the rated torque is given in the manual on both sides.
  • Measure that there is no gap between liner surface and screw landing surface after tightening, using a 0.05mm feeler gauge.
  • Disconnect the cylinder oil pipe connections. 
  • And screw of the non-return valves.
  • Dismount the four cooling water pipes between the cooling jacket and cylinder cover and clean them carefully.
  • Remove the screws of cooling water inlet pipe.
  • Attach the crossbar to engine room crane. This completes the lifting arrangement for cylinder liner.

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.

What to do if Cylinder Liner is Stuck
  • A common way to remove a stuck cylinder liner is to use hydraulic jacks on the bottom of the cylinder liner and apply hydraulic pressure.
  • Once the liner is slightly moved out of the stuck engine structure, it may be then lifted with the help of engine room crane and lifting tool
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
  • Make sure to inspect the liner for cracks and other defects

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