7 семестр (Бормотов А) / 1man_bw_l23_30_chn_23_30_instruktsiya_po_ekspluatatsii / MAN-BW L23-30 (ЧН 225_300)+ / MAN-BW L23-30 H Vol-1 (Instruction)+

08028-0D/H5250/94.08.12

L23/30H

Mounting of Tools

1)Mount the lifting device comprising eye screw, shackle and wire rope on the piston.

2)Lift up the piston and connecting rod and mount the piston and scraper rings, see point 14, and working card 506-01.10.

3)Remove the backstop for cylinder liner and place the piston guide ring on top of the cylinder liner, see fig 1.

Note: A crank throw position of approx 50 degrees before TDC will ensure this and also be suitable for the further mounting procedure.

Mounting of Big-end Bearing

6) Lower the piston further down, lubricate the ends of the bearing shells (as in fig. 2) with copaslip, molycote pasta or similar and mount the upper shell of the big-end bearing.

Fig 1.

Lowering of Piston and Connecting Rod

4)When the piston approaches the guide ring, stop the lowering, coat guide ring, piston, piston rings and scraper ring, with clean lubricating oil in order to minimize friction during the subsequent lowering of the assembly.

5)Make sure that the crank throw is in a position allowing the connecting rod to go clear of both crank journal and cylinder liner skirt during further lowering.

Fig 2.

7)Coat the crank journal with clean lubricating oil.

8)Lower the piston and connecting rod slowly into correct landing on the journal.

During this the connecting rod must be guided by hand to ensure correct approach and landing on the journal, see fig 3.

08028-0D/H5250/94.08.12

08028-0D/H5250/94.08.12

Fig 3.

Mounting of Bearing Cap

9) Mount the bearing cap with inserted lower shell of the big-end bearing, using the guide pin, see fig 4.

Con. Rod - Ident No.

Fig 4.

Fig 5.

Tightening of Connecting Rod Screws

13) Tighten the screws according to "Tightening Procedure for Connecting Rod Screws", see working card 506-01.25.

Fitting of Piston and Scraper Rings

14) Piston rings should only be removed from and fitted to the piston by the use of a special tool, the socalled piston ring opener.

If the rings are opened further than necessary there is a risk of overstressing, which means that rings will become permanently distorted and will not confirm to the inner running surface of the cylinder.

The piston rings should be installed with the identification mark, which is stamped into the ring close to the ring joints, facing upwords, see working card 50601.10 "Piston".

Ring joint

Fig 6.

Before fitting the coil spring loaded scraper ring, the coil spring is dismantled from the ring by removal of the joint pin. The coil spring is placed and assembled in the ring groove. Then the scraper ring is fitted in the groove in such a way that the ring joint is approximately 180° offset to the spring joint.

Ascertain correct assembling by checking the back clearance.The back clearance is sufficient when the face of the ring is below the groove edge when the ring is pressed against the bottom of the groove.

When installed on the piston the rings should be pushed back and forth in the grooves to make sure that they can move freely. It is also advisable to insert a feeler gauge of adequate thickness between ring and groove.

Adequate clearance is present so the feeler gauge can be moved all the way round.

To prevent gas leakage through coinciding ring joints the piston rings should be turned into positions offsetting the ring joint 180° to each other.

08028-0D/H5250/94.08.12

Starting Position:

Piston, connecting rod, bearing shells and bearing

Related Procedure:

1)Screw the studs pos. 3 down by hand into the connecting rod body pos. 1.

2)Fit the upper part of the connecting rod pos. 2 and hold it with nuts pos. 4.

Note. Remember to fit the bearing shells (unless the mounting is carried out for finish-machining).

3)Screw the studs to the bottom. Check the distance 81 from surface of upper part pos. 2 to the end of the studs pos. 3 and hand-tighten the nuts pos. 4.

4)Mount the hydraulic jacks pos. 5.

Note. Turn the thrust piece of the jack so that the slots for the ball handle pos. 6 are unloaded when pressurizing the jack.

5)Connect the jacks to the hydraulic system/ pumpby using the angle piece pos. 7.

6)Load the studs with the hydraulic pressure and tighten the nuts with the ball handle pos. 6

7)Relieve the tool pressure.

8)Re-apply the tool pressure.

9)Tighten the nuts again.

Note. Item 8 and 9 are carried out in order to eleminate any harmful stresses.

10) If any clearance is still visible and the nut can be turned, then repeat item 7, 8 and 9.

08028-0D/H5250/94.08.12

Safety precautions:

Stopped engine

Shut-off starting air

Shut-off cooling water

Shut-off fuel oil

Shut-off cooling oil

Stopped lub. oil circul.

Description:

In-situ inspection and/or replacement of connecting rod big-end bearing, dismounting and mounting.

Top cover for cylinder head removed.

Tool combination for tightening of connecting rod screw, see working card 520-01.20.

Hand tools:

Open-end spanner 24 mm.

Replacement and wearing parts:

Dismounting of Bearing Cap

3)Remove the fuel injector.

4)Insert the long-eye bolt and screw it into the thread hole in the piston, see fig 2.

5)Tighten it slightly by means of a tackle, see fig

2.

Removal of Bearing Shells

6) Dismount the bearing cap and bearing shell. For use of guide pin, see working card 506-01.00.

7) Lift the piston/connecting rod from the bearing journal.

Note: the piston/connecting rod should be lifted further then, just to allow dismounting of the upper bearing shell, see fig 2.

Inspection of Bearing Shells

8) Inspect the bearing shells, see working card

506-01.16.

08028-0D/H5250/94.08.12

Fig 3.

Cleaning of Components before Mounting.

9) Clean all components, see working card 50601.20.

Mounting of Upper Bearing Shells

10) The bearing shell is placed in the bore, the contact surfaces of the shells to be in parallel to the contact surface of the connecting rod and the bearing cap respectively.

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11)Ascertain that the crank throw concerned is in a position of approx 50 degrees before TDC.

12)Coat the journal with clean lubricating oil and lower the piston and connecting rod assembly slowly into correct landing on the journal.

While lowering the connecting rod, it must be guided by hand to ensure a correct approach and landing on the journal, see fig 4.

13) Lubricate the ends of the bearing shells (as in fig 2) with copaslip, molycote or simular.

Mounting of Bearing Cap

14)Mount the bearing cap with inserted lower bigend bearing shell, using the guide pin.

15)Lubricate threads and contact face of the connecting rod screws with copaslip or similar.

16)Mount the screws and tighten them slightly using an open-end spanner.

17)Slacken the tackle and dismount the eye screw from the piston crown.

Tightening of Connecting Rod Screws

18) Tighten the screws according to "Tightening Procedure for Connecting Rod Screw", see working card 506-01.25.

08028-0D/H5250/94.08.12