BMW 3 series E30

Since 1983-1994 of release

Repair and car operation

14.32. The belt is guilty, and we blame the generator

THE GENERAL DATA

Sooner or later each motorist should replace an old belt with the new. And as a rule, here any special questions does not arise, if it is required to replace a belt of a drive of the generator – there would be it near at hand a necessary minute. More often on a drive of generating installation the belt having клиновую the form of cross-section section is used and it settles down in a corresponding flute of pulleys. It can be made with a teeth or without them. In transfer happens one or several belts. In many respects it depends on transferred capacity on a drive of the generator, oil and water pumps and other consumers of energy. Some thin belts apply instead of one thick by transfer of the big effort, high speed at small diameters of the leader and conducted pulleys for the purpose of reduction of pressure of a bend in a material. At the expense of it the durability of a belt increases.

It is necessary to note advantage of a belt drive – smoothness and noiselessness of work. She does not demand additional service, for example, greasings, protects knots from an overload for the account проскальзывания.

Working surface are lateral sides, and the effort is transferred at the expense of a considerable friction (jamming) of a belt in a pulley flute. Therefore, if you see that the belt works as the bottom surface, it is necessary to replace it – it will soon fail.

The weak tension of a belt leads пробуксовыванию under loading. It becomes frequent the reason of bad work of generating installation. The belt is guilty, and we blame the generator. Thus more often at belt towing are audible "взвизги". Work of the water pump that can lead to an engine overheat worsens. But the last happens much less often.

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

The inquiry

The increase in 2 times of loading reduces term of its service to the bearing in 8 times. Therefore the excessive effort should not be applied.

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

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

If at you during movement the generator belt (it often results also a water pomp) was broke off, it will be appreciable by the gauge of temperature of a cooling liquid – the temperature raises, and on the ampermeter – will show the battery category (the arrow will deviate aside "minus"). For such a case we advise to carry with themselves spare, and it is better not to lead up to this condition: sometimes at breakage belt pieces get between a radiator and the fan that leads to destruction of tubes of cooling.

In modern cars are applied not only клиновые belts, but also gear which are used in synchronous transfers on drives of the fuel pump of a high pressure (ТНВД) and газораспределительного the mechanism (ГРМ).

For correct installation of gear belts in these transfers combination of corresponding labels on gear pulleys of cranked and distributive shaft with corresponding labels on a belt and labels on covers is necessary.

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

If to consider chain transfer for a drive газораспределительного the mechanism here there are more than lacks than advantages.

Advantages: the raised durability of a steel chain in comparison with a belt that gives the chance transfers большей to capacity. Whether but such big capacity on drive ГРМ is required? Certainly, no.

It is a lot of lacks: deterioration of hinges of a chain, additional loadings, necessity of greasing, deterioration of asterisks. But the basic lack – the raised noise level.