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)+

L23/30H

Measurement of Cylinder Diameter

While the piston is removed from the cylinder, the latter is measured to record the wear. The measurements are taken by means of an inside micrometer, with measuring points at TDC-position for uppermost piston ring, halfway down and at the bottom of the cylinder liner, see fig 1 and page 4.

Fig 1.

The measurements should normally be taken in transverse as well as in longitudinal direction.

When measuring, take care that the measuring tool has the approximately same temperature as the liner. When the wear of a cylinder liner exceeds the value indicated on page 500.35, i.e. when it becomes too troublesome to maintain satisfactory service conditions,thecylinderlinerinquestionshouldbeexchanged.

Honing the Cylinder Liner

The renovation can be made either with dismantled liner in the workshop or with liner mounted in the engine frame and by the use of the belonging funnel.

Prior to honing, deposits of coke and possible wear edges in the top of the liner must be removed by scraping.

If the cylinder is of the flame ring type, the used flame ring has to be cleaned in water. Subsequently, the flame ring is remounted in the cylinder before carrying out the honing process.

Note: After the honing process has taken place the used flame ring is discarded. A new flame ring is always mounted in the cylinder when replacing a piston ring.

80-160 rpm.

Fig 2.

The honing is made by means of a flex-honer with fineness grains 80-120. A revolution speed between 80 and 160 rpm is chosen.

08028-0D/H5250/94.08.12

In order to achieve the required angle between the honing grooves, see fig 2, the vertical speed is adjusted to about 1 m/sec. which corresponds to about 2 sec. for one double movement (the flexhoner is led from below up and down in 2 sec.)

The procedure is to be continued until the cylinder wall is covered by honing grooves and the surface has a slight matt appearance without any signs of glaze.

During the honing it is important to lubricate freely with honing oil or cutting oil.

After the honing, the liner is carefully cleaned with gas oil. Make sure that all abrasive particles have been removed.

60°

Fig 3.

08028-0D/H5250/94.08.12

Description:

Replacement of cylinder liner.

Hand tools:

Adjustable spanner.

Starting position:

Cylinder head and piston/connecting rod dismantled,working card 505-01.00 and 506-01.00.

L23/30H

Dismounting of Cylinder Liner

1) Prior to mounting of the lifting tool and dismounting from the frame, it must be ensured that the liner and frame have been marked to match, for the sake of a possible remounting of the liner, see fig 1.

Hole for charging air

Hole for roller guide house

Marking scratch frame

Marking scratch liner

Fig 1.

2)Mount the lifting tool as shown, see fig 2.

3)Turn the lifting eye nut to pull out the liner until the upper edge of the liner lie aligned against the copper protecting pieces of the cross bar.

4)Attach a tackle hook to the eye nut or the wire and the cross bar, and lift the liner out from the engine frame and put it down onto wooden supports.

5)Clean all parts and inspect for damage and wear according to the description. For measurement of cylinder liner, see working card 506-01.35.

Fig 2.

Mounting of Cylinder Liner

6)Check that the sealing surfaces on engine frame, cylinder liner, and sealing rings are perfectly clean.

7)Mount the lifting tool, attach a tackle hook to the eye nut or to the wire in the cross bar and lift the liner.

8)Check that the O-ring grooves are clean. Mount the O-rings and lubricate with a little oil.

9)Lower the cylinder liner carefully into the engine frame.

When the first O-ring touches the sealing face, align the liner so that the scratch mark on the liner flange points to the scratch mark on the frame as illustrated.

10) Mount the piston/connecting rod and cylinder head according to working card 506-01.20 and 50501.40.

08028-0D/H5250/94.08.12

Fig 1.

Grinding

1)Loosen the sealing ring in liner flange and take

it out.

2)Face-grind the sealing grooves in the cylinder liner flange, see Fig 2, and the sealing surface on the cylinder head, see Fig 3, with the use of grinding pasta and the grinding tool.

Fig 3.

3)After grinding, remove all traces of abrasives and grinding compound.

4)When having ground the contact faces, it must be observed that the gap between cylinder head and liner is no less than 0.5 mm, i.e. the difference between measurements y and z must not be less than

0.5mm, see Fig 4.

08028-0D/H5250/94.08.12

L23/30H

Dismantling of Piston at Low Overhaul Heights

1)Lift up the piston and the connecting rod through the cylinder liner until the piston is clear of the liner.

2)Mount the collar on the connecting rod, see plate 52050, item no 045.

3)Place the piston with the collar on the cylinder

liner.

4)Mount pull-lifts on the collar.

Dismantling of Cylinder Liner at Low Overhaul

Heights

1)Mount the normal lifting tool for cylinder liners.

2)Carefully pull the cylinder liner half-way out of the frame.

3)Mount a special lifting tool for cylinder liners at low overhaul heights, see plate 52050, item no 033.

4)Attach pull-lifts on the lifting tool for the cylinder liner, see plate 52050, item no 033.

5)Take out the liner over the camshaft side.

Plate

Page 1 (2)

Piston and Connecting Rod (Hydraulic Tightened) 50601-05H