Opel Corsa B, Combo, Tigra

Since 1993-2000 of release

Repair and car operation

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

Condition check

In spite of the fact that bearings of a cranked shaft in the course of engine major repairs are subject to replacement without fail, old loose leaves should be kept for the purpose of attentive studying of their condition which results can give a lot of helpful information on the general condition of the engine. On an accompanying illustration examples of typical defects of loose leaves of bearings are resulted.

Typical examples of deterioration of bearings

FATIGUE DEFORMATION

DIRT HIT

EXCESSIVE DETERIORATION

WRONG LANDING

GREASING LACK

КОНУСНОСТЬ NECKS

The exit of bearings out of operation can occur owing to a lack of greasing, hit of particles of a dirt, overloads of the engine and corrosion development. Without dependence from character of defects, the reason of damage of loose leaves should be eliminated in the course of performance of major repairs of the engine in order to avoid relapse.

For survey take loose leaves of bearings from the beds in the engine block / the bottom heads of rods and radical/shatunnyh covers and spread out them as installation on a pure working surface. Organisation of placing of loose leaves will allow to adhere character of the revealed defects to a condition of corresponding necks of a shaft.

The dirt and extraneous particles get to the engine various ways. They can be left in the block in the course of unit assemblage, or get through filters or ventilation system картера. All particles getting to impellent oil, finally, sooner or later, appear in bearings. Often the metal sawdust formed in the course of normal operation of internal components of the engine takes root into a soft material of loose leaves. The probability of presence at bearings of traces of an abrasive is great, in particular, when the proper attention has not been given cleaning of the block after end of regenerative repair of the engine. Without dependence from a way which extraneous particles get to the engine, as a result they with high degree of probability appear introduced in a soft surface of loose leaves of bearings of a cranked shaft and easily come to light at visual survey of the last. Large particles usually are not late in loose leaves, but leave on their surface and a surface of necks of a shaft appreciable traces in the form of scratches, cavities and задиров. The best guarantee from such troubles is the responsible relation to cleaning of components after end of major repairs of the engine and carefulness of observance of cleanliness at assemblage. Frequent regular change of impellent oil also allows to prolong service life of bearings essentially.

Oil starvation can be a consequence of several various, but often interconnected phenomena. So, the engine overheat conducts to разжижению engine oil and to its replacement from working backlashes of bearings. The lack of greasing of bearings can speak in excessive size of working backlashes, and also usual leaks (internal or external). Often meeting reason of replacement of oil from backlashes of bearings is constant excess of turns of the engine. Passableness infringement маслотоков (usually connected with wrong combination of apertures at installation of components) also conducts to reduction of giving of greasing to bearings. Typical result of oil starvation is the full or local wipe/vyshcherblivanie of a blanket of loose leaves from a metal substrate. Thus the working temperature can rise to such level that the substrate as a result of an overheat gets a bluish shade.

Essential influence on service life of bearings is rendered also peculiar to the owner of the car by a driving manner. Movement with small speed on the raised transfer leads to considerable overloads of the bearings, accompanied replacement of an oil film from their working backlashes. Such overloads lead to increase of plasticity of loose leaves and occurrence of cracks in a blanket (fatigue deformation). Thus the superficial material starts to crumble and separate from a steel substrate. Car operation in a city cycle (on short distances) conducts frequent trips to development of corrosion of bearings because the insufficient warming up of the engine involves loss of a condensate and allocation of chemically aggressive gases. The given products accumulate in impellent oil, forming slags and acids. At hit of such oil in bearings aggressive substances promote development of corrosion of loose leaves.

Wrong installation of loose leaves in the course of engine assemblage also can be at the bottom of their fast destruction. Too hard landing does not provide the demanded size of a working backlash of bearings that leads to their oil starvation. Result of hit under loose leaves (in the course of their installation) extraneous particles is formation of eminences the blanket with which is quickly wiped.

Selection of loose leaves

In case of deterioration or damage of loose leaves of bearings, and also when it is not possible to achieve correct size of a working backlash, the situation can be corrected in the way described more low, by selection and installation of new loose leaves. Without dependence from a technique of definition of the demanded size of loose leaves working backlashes of bearings should be then are checked up with application of measuring set Plastigage.

If it is not possible to correct properly size of working backlashes by selection of loose leaves, it is necessary to replace a shaft.

Usually selection of loose leaves is carried out by the experts making проточку of necks of a shaft. The standard size of new loose leaves is defined by depth проточки necks. Проточка it is usually carried out with step of 0.25 mm. In certain cases radical and шатунные necks are pierced on various depth. The pierced shaft usually in appropriate way is marked. So, for example, type "10-10" marks usually mean that both complete sets of necks are pierced on depth of 0.010 inches (0.25 mm) and it is necessary to select loose leaves of the corresponding size with belittling. Identification marks on the back party of the loose leaf are used by experts at definition of dimensional group of bearings.