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

Plate

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L23/30H

720/750 RPM

08028-0D/H5250/94.08.12

Index

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Description

General

The camshaft which controls the actuation of inlet valves, exhaust valves and fuel injection pumps is driven by a gear wheel on the crankshaft through an intermediate wheel, and rotated by a speed which is half of that of the crankshaft, see fig. 1.

The camshaft is located in a high level housing in the engine frame.

The camshaft runs in replaceable, identical, steelbacked bronze bushings fitted into borings of the transverse girders in the housing.

The camshaft is built-up of sections, one for each cylinder unit. Each section is equipped with fixed cams for operation of fuel injection pump, air inlet valve and exhaust valve. The sections are assembled by bolting of the ample dimensioned and precision made flange connections, which also act as bearing journals.

Except for the foremost and the aftmost ones, the sections are identical and therefore interchangeable. The foremost section is equipped with a clutch for driving the fuel oil feed pump (if mounted). The gear wheel for driving the camshaft as well as a gear wheel connection of governor are screwed on the aftmost section.

L23/30H

The lubricating oil pipes for the gear wheels are equipped with nozzles which are adjusted to apply the oil at the points where the gear wheels are in mesh. The position of the nozzles is determined by direction of rotation of the engine.

Engine seen from aft - fly wheel end

Clockwise rotation direction

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:

Checking of gear wheels, bolted connections and lubricating system.

Starting position:

Related procedure:

Hand tools:

Allen key, 12 mm.

Ring and open end spanner, 19 mm. Socket spanner, 19 mm.

Replacement and wearing parts:

L23/30H

1) Dismount the covers which give access to the gear wheels, camshaft and crankcase.

Examine all gear wheels for cracks, wear and deformations. While turning the engine to enable inspection allover the circumference of the gear wheels.

2) Check all screws, nuts and bolted connections, including locking devices everywhere in the gear wheel housing, camshaft housing and crankcase to check that they have not worked loose. Tightening torques, see page 500.40.

3)Examine all lubricating oil spray pipe nozzles.

4)Start the electrical lubricating oil pump and check the oil flow everywhere. Be particularly careful to check that the oil jet hits the gear wheels correctly at the points where the wheels mesh.

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:

Check of roller path of cams and check of camshaft bearing.

Replacement of camshaft bearing.

Starting position:

Cover for camshaft and gear wheel has been removed.

Related procedure:

Hand tools:

Ring and open end spanner, 19 mm. Socket spanner, 19 mm.

Feeler gauge. Big screw driver.

Replacement and wearing parts:

L23/30H

To Check Roller Path of Cams.

1) While turning the engine, examine the cam discs and in particular, check the roller path of all cams for cracks, crackles and ruffle. Also examine the rollers of the roller guides.

Note: if there are flat spots on the roller and if some of the rollers may be blocked, the roller must be replaced by a new one, see working card 508-01.00.

To Check Camshaft Bearings.

2) The wearing surface of the camshaft bearings cannot be checked without dismounting the camshaft. However, ab-normal wear of one or more bearings will become apparent in the form of burrs of white metal at the circumference of the camshaft journal, and in that case the bearing will in no doubt be discoloured, as well.

The bearing clearance is measured with a feeler gauge, see data sheet 500.35.

To Replace Camshaft Bearing.

3) If one or several of the camshaft bearings should be replaced, the camshaft must be wholly or partly dismantled.

Dismount the fuel oil feed pump, if mounted, and check that the camshaft sections are marked in relation to each other. Disassemble the camshaft aft (toward flywheel) of the bearing that is to be replaced. Dismount all roller guides that are located forward of the disassembling position, see working card 508-01.00 and 508-01.05.

Pull the disconnected sections of the camshaft so far a head that the bearing which is to be replaced is free.

Take out the locating screw of the camshaft bearing concerned and push the bearing out of the bore in the engine frame, see fig 1.

Check the lubricating oil ducts to the bearing for free flow.

Camshaft bearing

Hole for lubricating oil

Locating screw

Frame

Fig 1.

Mount a new camshaft bearing in the bore and make sure that the hole for insertion of the locating screw in the bearing is in a correct position. Lock the bearing by means of the locating screw, which is to be provided with a new gasket. To facilitate the fitting of the bearing it can be cooled down with Co2.

Inspect the camshaft journal for seizures.

If necessary, the camshaft section must be entirely removed from the engine, and the journal concerned must be polished.

Coat all the journals of the camshaft section with clean lubricating oil and push the camshaft into position, making sure that the marks on the flanges coincide.

Assemble the sections and fit the bolts (coated with copaslip or similar).

Tighten the nuts with a torque spanner, see data sheet 500.40.

Mount all roller guides as well as the fuel oil feed pump.

08028-0D/H5250/94.08.12

08028-0D/H5250/94.08.12