Lesson 31 Main Engine Repair (II)

 1. Crankpin bearing overhaul  2. Fuel pump removal & re-installation  3. Cylinder head removal/replacement  4. Piston removal/replacement  5. Cylinder liner removal/replacement

Method of removal: Bearing clearances are to be taken and recorded. Turn the crank to TDC. Slacken and remove the lock nuts. Slacken crankpin bearing bolts and remove the hydraulic jacks and the nuts. Lower the bearing cap Landing the bearing cap on wood in the oil pan.

 The steps to be followed: ① Allow to remove all F.O. H.P. pipes for access and re-install as original. ② Remove fuel piping from pump and disconnect the fuel rack linkage. ③ Measure the lead of the fuel pump. ④ Turn the engine until the piston is at BDC ⑤ Lift the roller guide. ⑥ Remove the top cover. ⑦ Remove the holding down bolts and lift out the fuel pump body, plunger & barrel complete, from it’s housing. ⑧ Remove the rollers and guides for all the fuel P/P’s for checking of cracks by MPI. ⑨ Open and clean the shock absorbers and renew “O” ring and sealing ring with ship’s spares.

 The cylinder cover is made of steel and has a central bore for the exhaust valve. The cover furthermore has bores for the fuel valves, starting valve, safety valve and indicator cock.  Cylinder head cooling: drilling type

A. Dismantle exhaust bellows between exh. v/v & main exhaust trunk. B. Remove hydraulic pipe for exh. v/v actuator. C. Remove cooling water bends & HP fuel pipes. D. Rig hydraulic tools for releasing the cylinder head nuts. E. The head should be inspected by the Owner’s representative and/or the attending class surveyor.

 The procedures: ① Remove the cylinder head. ② Disconnect the piston rod palm from the cross-head inside the crankcase ③ Remove the stuffing box retaining bolts. ④ Turn the piston to TDC and attach the piston lifting device. ⑤ Remove the piston and rod. ⑥ The cylinder liner, scavenge ports and scavenge space are to be cleaned in- situ removing any sludge and carbon deposits. ⑦ Operation of the cylinder lubrication quills is to be verified after cleaning. ⑧ Remove the piston rings and clean carbon and other deposits from the piston crown and the ring grooves.

⑨ The stuffing box is to be stripped down and all parts thoroughly cleaned before calibrating the sealing rings as described in the maker’s manual and the stuffing box is to be re-assembled on the piston rod. ⑩ After being thoroughly cleaned the piston ring grooves are to be calibrated and the readings recorded. 11 New piston rings are to be installed. 12 The parts are to be inspected by the owner’s representative and / or the attending class surveyor. 13 The ring guide device is to be installed on the cylinder liner joint face then the piston is to be re-installed in the liner. 14 All readings taken are to be reported on a and presented to the Owner’s representative or C/E.

A. Remove the cylinder head. B. Remove the piston & rod. C. Remove the cylinder lubricator quills. D. Remove the cylinder jacket. E. Attach the liner lifting tool and lift the liner from the entablature. The removal/replacement procedure:

 1. Review the text.  2. Do the exercises on P259.