Citroen Xantia

Since 1993 of release

Repair and car operation

Check of a condition of loose leaves radical and шатунных bearings of a cranked shaft

Typical examples of deterioration of loose leaves of bearings of a cranked shaft

And — Are scratched by alien particles - the particles which have plunged into a working layer of the loose leaf are visible
In — an oil Lack - the top layer is erased
With — Loose leaves are incorrectly located at installation - there are brilliant (polished) sites
D — the Neck is shown on a cone - the top layer is removed from all surface
Е — Deterioration of edge of the loose leaf
F — Malfunction of "weariness" - craters or pockets were formed

Despite compulsion of replacement of loose leaves radical and шатунных bearings in the course of performance of major repairs of the engine, it is necessary to subject a condition of old loose leaves to attentive studying as on it it is possible to gather a lot of helpful information on the general condition of the engine. Loose leaves of bearings are graduated on a thickness and the accessory to their this or that dimensional class is defined on colour marks.

The exit of bearings out of operation can result from a lack of greasing, hit of a dirt or extraneous particles, overloads of the engine, development of corrosion and other adverse influences. Examples of the most typical defects of loose leaves of bearings of sliding are resulted on an illustration Typical examples of deterioration of loose leaves of bearings of a cranked shaft. Without dependence by nature defect, the reason of its occurrence should be revealed and eliminated prior to the beginning of assemblage of the engine in order to avoid relapses.

For survey take loose leaves from the beds in the block of cylinders/kartere of the engine, radical and шатунных covers and the bottom heads of rods. Spread out the removed loose leaves on a pure equal working surface as an arrangement on the engine that it was possible to correlate their condition with a condition of corresponding necks of a cranked shaft. Try not to touch working surfaces of loose leaves with hands in order to avoid casual damage of a soft material.

The dirt and extraneous particles get to the engine various ways. They can be left inside after major repairs end, get through filters or ventilation system картера. Often the dirt gets at first to impellent oil and already together with it gets into bearings. It is not necessary to forget that in the course of normal deterioration of the engine metal sawdust is inevitably formed. If after performance of a recovery work the proper attention is not given procedure of cleaning of the engine, in it by all means there are abrasive particles. Without dependence from a way of penetration into the engine, all extraneous particles appear sooner or later introduced in a soft surface of loose leaves of bearings of sliding and are easily distinguished at visual survey of the last. The largest particles usually do not jam tightly in loose leaves, but deep furrows and teases leave on their working surfaces and surfaces of corresponding necks of a shaft. The best protection against occurrence of such defects is the conscientious attitude to performance of cleaning of the engine after end of major repairs and installation during assemblage only absolutely pure components. Also it is not necessary to forget necessities of performance of regular and frequent change of impellent oil.

Oil starvation also can be caused the several reasons frequently closely interconnected with each other. That concern: the engine overheat (the leader to разжижению oils), overloads (in which result oil is superseded from bearings), oil leaks (connected with excessive size of a working backlash in bearings, deterioration of the oil pump, or excessive increase of turns of the engine), etc. passableness Infringement маслотоков, more often connected with negligence of installation of components at the assemblage conducting to рассовмещению of oil apertures, also causes reduction of giving of oil in bearings and, finally, to an exit of loose leaves out of operation. A characteristic sign of oil starvation is the wipe and replacement of a soft working layer of loose leaves from their steel substrate. Sometimes the temperature raises to such degree that on a steel substrate as a result of an overheat violet stains are formed.

It is necessary to remember that essential influence on service life of bearings is rendered by a driving manner. To loading increase on the engine promote frequent full opening throttle заслонки, movement on small turns, etc. As a result occurs replacement of an oil film from a working backlash of bearings that conducts to a softening of loose leaves of the last and formation on their working surface of small cracks (fatigue deformation). Finally occurs отслоение separate fragments of a material of a working layer and вырывание them from a substrate.

The driving manner also appreciably affects service life of bearings. Movement with completely open throttle заслонкой, movement on a hill-climbing gear conduct to strong overloads of bearings and squeezing from working backlashes of an oil film. Thus the material of loose leaves is softened, and a working layer растрескивается. Such modification подшипниковых surfaces is called as fatigue deformation. As a result in due course the working layer starts to separate fragments from a substrate and bearings become unfit for use.

Car operation in a city cycle is frequently connected with fulfilment of set of short trips that conducts to development of corrosion of bearings as insufficient warming up of the engine promotes loss in it a condensate and to formation of caustic gases. Aggressive products accumulate in impellent oil, forming шлам and acid and as oil continuously arrives in bearings, finally, influence a material of loose leaves of the last, causing its oxidation and destruction.

Wrong installation of loose leaves at engine assemblage also conducts to their fast destruction. At too dense landing it is inadmissible the size of a working backlash that is at the bottom of oil starvation of bearings is reduced. Hit between backs of loose leaves and beds of bearings of extraneous particles conducts to formation of sites of an eminence of a working surface and destruction of last in the course of normal work of the engine.

As already it was mentioned above in this section, replacement of loose leaves at engine major repairs should be made without fail, without dependence from their condition (Installation of a cranked shaft and check of working backlashes of radical bearings) - attempt see to ignore the given requirement it is capable to lead to only seeming economy.