BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

+ 1. Maintenance instruction
+ 2. Maintenance
- 3. Engine
   - 3.1.2. Specifications
      3.1.3. Types of the repair work performed without dismantle of the engine
      3.1.4. Order of installation of the piston of the 1st cylinder in compression step VMT
      3.1.5. Cover of a head of cylinders
      3.1.6. The soaking-up collector
      3.1.7. Final collector
      3.1.8. Cam-shaft drive chain covers (M10 engine)
      3.1.9. Chain and asterisks (M10 engine)
      3.1.10. Covers of a gear belt (M20 and M40 engines)
      3.1.11. Gear belt and asterisks of a cam-shaft (M20 and M40 engines)
      3.1.12. Forward epiploons
      3.1.13. Head of cylinders
      3.1.14. Pallet
      3.1.15. Oil pump
      3.1.16. Flywheel (drive plate)
      3.1.17. Back epiploon of the crankshaft
      3.1.18. Engine mount details
   + 3.2. Dismantle and capital repairs of the engine
   + 3.3. Engine electric equipment
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
+ 14. Useful tips


3.1.11. Gear belt and asterisks of a cam-shaft (M20 and M40 engines)



Before removal of an asterisk on the M40 engine the special device for fixing of a cam-shaft is necessary.


1. Disconnect the battery from weight.
2. Uncover a gear belt.
3. On the M40 engine merge cooling liquid (see subsection 2.31) and remove the thermostat (see subsection 4.4).
4. Install the piston of the 1st cylinder in compression step VMT (see subsection 3.1.4).

After installation of the piston of the 1st cylinder in VMT of a step of compression and removal of a chain rotation of the crankshaft is not allowed, otherwise serious breakages because of impact of heads of valves with the bottoms of pistons are possible.

5. On the M20 engine check combination of a tag on a crankshaft sock nave with a tag on a back cover of a gear belt.
6. The tag on a cam-shaft has to be opposite to cast risks on a head of cylinders.
7. On the M40 engine apply orientation risks on an asterisk of a cam-shaft and a back cover which will be used at assembly.
8. On the M20 engine release bolts of a roller of a natyazhitel and displace a natyazhitel towards the pump of cooling liquid, having weakened a belt. Tighten bolts.
9. On the M40 engine release a nut of a natyazhitel and turn a natyazhitel clockwise, having weakened a belt. Tighten a nut.
10. Check existence on a rotation direction sign belt, at its absence put a tag (if the taken-off belt in the normal state and is established again).

The belt is recommended to be changed at each removal, irrespective of its state. On the M40 engine the belt should be replaced after each its easing. Keep in mind that at removal of a belt from an asterisk of the crankshaft it is necessary to make considerable effort.

11. Take off a belt from asterisks.
12. Turn off a cam-shaft asterisk bolt for what record it a leather tape or the old gear belt which is put on on teeths and compressed flat-nose pliers.
13. Record a cam-shaft from a provorachivaniye.


On the M40 engine the asterisk is fixed on a cam-shaft nonrigidly, the spline allows movement of a shaft of several degrees. Fixing of an asterisk is provided on a conical part of a shaft when tightening a bolt.

14. The device for fixing has to cover a 4-faced neck of a cam-shaft about 1 cylinder at right angle to a head of cylinders.
15. If necessary fix the crankshaft and turn off a crankshaft sock nave bolt. For fixing of the crankshaft BMW 112150 adaptation (M20 engine) or 112170 (M40) which maintains the considerable effort demanded for a bolt otvorachivaniye is used. It should be noted that BMW 112170 adaptation fastens to a head of cylinders and fixes a flywheel. Therefore it can be applied only if the check point or the engine are removed.
16. On engines with a two-level nave of a sock of the crankshaft after an otvorachivaniye of a bolt it is necessary to remove a stripper an asterisk for what it is necessary to wrap a crankshaft pulley bolt on 3 turns and to use it as a support for a stripper bolt.

Typical damages of a gear belt

1. Wipe of a cover and exposure of rubber

2. Stratification

3. Loss of teeths

4. Wear of persistence of a surface of teeths

5. Emergence of fibers of a basis

6. End face rounding off


1. Check a condition of a belt, replace at detection of any damages. Check a condition of teeths of asterisks, in case of uneven wear replace an asterisk.


When replacing these details address to car service. The asterisk, a belt and a roller of a natyazhitel of the M20 engine of late releases have marking of Z127. These details should be established in a set if details of former releases are absent.

2. Check freedom of rotation of a roller of a natyazhitel and a condition of a spring. When replacing a belt also the roller changes.


1. On the M20 engine establish a roller with a spring so that the belt could be put on freely.
2. Establish asterisks upside-down. On the M40 engine tighten a cam-shaft asterisk bolt with m 1–3 N.' moment, having turned an asterisk clockwise against the stop.
3. At installation of the taken-off belt orient it on the put tag specifying the direction of rotation.
4. Put on a belt on asterisks, having begun with a crankshaft asterisk.
5. Put on a belt on a roller of a natyazhitel.
6. On the M20 engine release bolts of a natyazhitel.
7. On the M20 engine make small effort under a roller of a natyazhitel, having convinced of freedom of movement of a plunger and of creation by a belt tension spring. At the same time not to tighten bolts.
8. On the M40 engine release a nut of a roller of a natyazhitel and turn a roller a 6-faced key counterclockwise to a belt tension. Control a tension of a belt on a special dynamometer, the normal tension corresponds to 32 (±2) divisions of a scale of the index.
9. The acceptable accuracy of a tension is reached by application of a 6-faced key with a spring steelyard. A steelyard arrange as it is shown in a picture, otherwise indications will be inexact because the roller of a natyazhitel is strengthened on the clown. The shoulder And a key has to have length of 85 mm, and the effort of 2,0 kgfs is made for a steelyard.
10. Check combination of all tags.
11. Turn the crankshaft on 2 turns.
12. On the M20 engine release bolts of a roller of a natyazhitel and tighten with the set moment.
13. On the M40 engine release a nut of a roller of a natyazhitel and tighten a cam-shaft asterisk bolt.
14. Be convinced of combination of all tags. If combination of tags is broken, then take off a belt and repeat the procedure of clothing of a belt.
15. Further assembly is carried out upside-down.