BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

Sooner or later each motorist should replace an old belt with new. And as a rule, here no special questions arise if it is required to replace a generator drive belt – there would be it near at hand the necessary minute. Most often on the drive of generating installation the belt having the maple form of cross section is used and it settles down in the corresponding flute of pulleys. It can be made with teeth or without them. In transfer there are one or several belts. In many respects it depends on the transferred power on the drive of the generator, oil and water pumps and other consumers of energy. Several thin belts apply instead of one big effort, thick by transfer, high speed with small diameters of the leader and the conducted pulleys for the purpose of reduction of tension of a bend in material. At the expense of it durability of a belt increases.

It should be noted the advantage of the belt drive – smoothness and noiselessness of work. She does not demand additional service, for example, of lubricant, protects knots from an overload due to slipping.

Working surface are side sides, and the effort is transmitted due to considerable friction (jamming) of a belt to a pulley flute. Therefore if you see that the belt works with the lower surface, it needs to be replaced – it will fail soon.

The weak tension of a belt leads to skidding under loading. It becomes frequent the reason of bad work of generating installation. The belt is guilty, and we blame the generator. At the same time most often when towing a belt "vzvizg" are heard. Operation of the water pump worsens that can lead to an engine overheat. But the last happens much less often.

The excessive, strong tension of a belt leads to its bystry wear, increases effort to bearings of a shaft of the water pump and the forward bearing of the generator.

Reference

Increase twice in load of the bearing reduces the term of its service by 8 times. Therefore the excessive effort should not be applied.

The normal tension is characterized by a certain deflection about 8-10 mm when pressing by a finger with effort of 3-4 kg to the middle of the site between a water pomp and the generator.

The tension of a belt is regulated most often by generator shift. For this purpose weaken a nut and bolts of fastening of the generator to a tension level and pull a belt by means of the lever. A hand it is difficult to execute it.

If at you during the movement the generator belt (it often gives also a water pomp) became torn, it will be noticeable by the sensor of temperature of cooling liquid – temperature increases, and on the ampermeter – will show the category of the battery (the arrow will deviate "minus" aside). For such a case we advise to carry with ourselves spare, and it is better not to bring to this state: sometimes at break pieces of a belt get between a radiator and the fan that leads to destruction of tubes of cooling.

In modern cars not only maple belts, but also gear which are used in synchronous transfers on drives of the fuel pump of high pressure (FPHP) and the gas-distributing mechanism (GRM) are applied.

The correct installation of gear belts in these transfers requires combination of the corresponding tags on cogged pulleys of cranked and distributive shaft with the corresponding tags on a belt and tags on covers.

As the break of a gear belt in operating time of the engine leads, as a rule, to considerable breakages of GRM and krivoshipno-piston group, it is necessary to replace them according to recommendations of manufacturer (approximately through 80 thousand km).

If to consider chain transfer for the drive of the gas-distributing mechanism, then there are more shortcomings than advantages.

Advantages: the increased durability of a steel chain in comparison with a belt that gives the chance of transfer of bigger power. Whether but such big power on the GRM drive is required? Of course, no.

There is a lot of shortcomings: wear of hinges of a chain, additional loadings, need of lubricant, wear of asterisks. But the main shortcoming – the increased noise level.