Toyota Corolla

1992-1998 of release

Repair and car operation

Check

In spite of the fact that radical and shatunny bearings at major maintenance of the engine are subject to the obligatory replacement, the bearings which were in operation should be stored in a place of their installation for careful check as wear tracks on these details allow to restore the general condition of the engine.

Causes of destruction of bearings of a cranked shaft are insufficient greasing, presence of dirt and extraneous particles, an overload of the engine and corrosion. Irrespective of the reason which has caused destruction of bearings, it is necessary to eliminate it before final assembly of the engine to avoid repeated damages of these details.

At check of a condition of bearings they should be got from seats (from the block of cylinders, covers of radical bearings of a cranked shaft, shatunny covers and rods) and to lay out on a pure surface in the same order in which they were established on the engine. It will allow to establish the corresponding support of a cranked shaft in which the bearing underwent the strengthened wear.

Dirt and extraneous particles get to the engine for various reasons, in the course of assembly, via filters or system of ventilation of a case. Pollution can get also to oil, and from it – in bearings. Often at pollution there are metal particles from machining of details of the engine, or owing to wear at normal operation of the engine. Sometimes at pollution there are remains of abrasive materials after carrying out pritirochny and grinding works, especially at insufficient washing and engine pro-cleaning after the completion of works. Irrespective of the origin reason extraneous pollution usually take root into a soft alloy of the bearing and are easily distinguishable. Large particles cannot take root into the bearing and lead to emergence of scratches and задиров on surfaces as bearing and crankshaft necks. The best way of the prevention of such wear is careful washing of details and maintenance of faultless purity at engine assembly. For the prevention of premature wear also it is recommended to a thicket to change oil and filters.

Insufficient greasing of the engine ("oil starvation") can be caused by a number of the interconnected reasons. Overloads concern them (cause expression of oil from a surface of bearings) and pressure decrease because of leakage (emission) of oil (because of the raised gaps in bearings, wear of the oil pump, big frequency of rotation of a cranked shaft) an engine overheat (causes razzhizheny oils). The reason of the accelerated wear of bearings of a cranked shaft also is blocking of oil channels, usually owing to a nesovmeshchennost of lubricant openings in the bearing and details of its case that causes insufficient greasing and failure. When a cause of destruction is insufficient greasing there is a wipe or expression of a material of a covering of the bearing from a steel basis. The temperature increases to such level that from an overheat there is a vykrashivaniye of a steel basis of the bearing which gets a bluish shade.

The durability of bearings of a cranked shaft also essentially depends on skills of driving and nature of movement. Bearings test the raised loadings at movement on small speed at the included overgear. At the raised loadings there is an expression of an oil film. Bearings test flexural deformations at which microcracks (fatigue wear) are formed. As a rule there is a separation of a covering of the bearing from a steel basis in the form of small particles. Trips on small distances can be at the bottom of corrosion wear of bearings as because of insufficient warming up skondensirovanny moisture and the gases causing corrosion do not manage to be removed. These components collect in oil, causing formation of acids and an insoluble precipitation. In process of intake of oil to bearings there is a corrosion under the influence of acids, causing destruction of bearings and failure.

The exit of bearings out of operation can be caused also by the wrong installation at engine assembly. Too small gap in bearings is at the bottom some insufficient greasing and the increased wear. Dirt and the extraneous particles which have got under the back party of the bearing, cause its non-uniform prileganiye and premature failure.

Selection

If the bearings which were in operation are worn-out or have damages, or the gap in bearings does not correspond to norm (see subsection 3.1.2.17 and subsection 3.1.2.19), for selection of bearings it is necessary to execute certain actions which are described below. Nevertheless, if the crankshaft перешлифовывался, it is necessary to establish new repair loose leaves, – in this case described procedures not to apply! In a workshop in which the crankshaft was under repair, will help you with a choice of loose leaves of the suitable size. Irrespective of a way of determination of the size of loose leaves measure a gap in bearings by means of a plastic calibration wire. It measurements are defining at installation of loose leaves.