Disassembly of the cylinder block of the K4M engine

For a major overhaul of the engine, we dismantle the cylinder block.

1. We fit the flywheel locking tool Mot582-01 or Mot1677 (see the arrow, Fig. 1).
2. We remove the clutch pressure disc and the driven disc. It is recommended to mark the mutual position of the clutch housing and the flywheel so that no balancing problems arise during assembly, especially when these same parts are subsequently reassembled.

3. We remove the flywheel (see Fig. 2). It is recommended to mark the position of the flywheel on the crankshaft flange. These two parts are balanced as an assembly, so a different mutual position may upset the balance, especially if repair or replacement of these parts is not intended.

4. We unscrew and remove the engine oil sump (see Fig. 3).

5. We remove the timing belt drive tensioner roller (see Fig. 4).

6. We unscrew the bolts and remove the water pump (Figure 5).
7. Remove the front cover of the engine block.

8. We remove the oil level sensor (see the arrow, Fig. 6) and the oil baffle (sump).
9. Mark the upper part of the connecting rod and its cap with a marker. It should be borne in mind that the bearing shells have no bent locating tab, while the tab groove on the connecting rod exists and serves to orient the rod relative to the piston. To facilitate assembly, mark the side of the rod facing the flywheel.

Note. Do not use a centre punch or engraving tool to mark the upper part and the cap of the connecting rod, as this may lead to subsequent failure of the rod in service. Use an indelible marker.

10. Unscrew the connecting rod cap retaining nuts (see Fig. 7) and carefully remove the connecting rod caps with the bearing shells.
11. Remove the pistons with connecting rods as an assembly, the oil pump drive chain and the oil pump. Set aside the second half-shells of the connecting rod bearings.

Note. The pistons with connecting rods are withdrawn towards the cylinder head; wrap the lower connecting rod eye with tape so as not to scratch the cylinder walls.

12. Remove the crankshaft main bearing caps (the bearing caps are numbered from 1 to 5) (see Fig. 7).
13. Withdraw the main bearing half-shells from the caps.

Note. Be sure to mark the main bearing shells and the crankshaft supports, since bearing shells of different sizes may be fitted to one engine.

14. Remove the crankshaft (see Fig. 8) and withdraw the lower bearing half-shells.

Removing the piston cooling nozzles

The nozzles serve to direct a jet of oil from below onto the piston crowns; this intensifies piston cooling in service, which has made it possible to reduce their weight and increase the effective engine power.

The nozzles can only be removed by destroying them; otherwise no supporting surface can be created for the puller. During assembly the nozzles will have to be replaced with new ones. On the other hand, without removing the nozzles it is impossible to clean the engine oil supply channels to the nozzles. With poor maintenance and cheap engine oil, this can lead to a reduction or even cessation of engine oil supply for piston cooling, which risks melting the pistons in service.

1. Drill the body of the piston cooling nozzle from above with a 7 mm drill; the swaged edge retaining the plug (1) must be removed (see Fig. 9).
2. Do not remove the ball (3), so that swarf does not enter the oil channel (see Fig. 9).
3. Remove the plug (1) and the spring (2).
4. Remove the metal filings with a brush.

5. Screw the adapter Mot1485 or Mot1485-01 into the nozzle (see Fig. 10).
6. Screw the inertia puller Emb880 into the adapter.
7. Remove the nozzles using the inertia puller.

Cleaning the lower part of the engine

Clean the following assemblies with the DECAPJOINT product to dissolve adhering gasket residues:

• cylinder block;
• crankshaft;
• engine oil sump;
• front cover of the engine block;
• crankshaft main bearing caps.

Apply the product to the surface to be cleaned, wait about 10 min, then remove it with a wooden scraper. Do not clean the mating surfaces of aluminium parts with sharp-edged tools. Do not allow the cleaning agent to come into contact with paint coatings.

Carry out the cleaning carefully, do not allow dirt to enter the channels supplying oil to the hydraulic tappets and camshafts (the channels are located in the cylinder block and the cylinder head) or the oil drain channels. If this requirement is not met, the oil supply channels may become blocked, which will lead to rapid engine failure.

Blow all oil channels with compressed air; if a channel is blocked, clean it with soft wire and flush it with special products.

Next we prepare all parts for inspection and fault assessment.

After that we reassemble the engine. These points will be covered in the following articles.