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1. Despite obligation of replacement of inserts of radical and conrod bearings in the course of performance of capital repairs of the engine, the condition of old inserts needs to be subjected to the most attentive studying as from results of such analysis it is possible to gather a lot of useful information about the general condition of the engine.
2. An exit of bearings out of operation can result from a lack of lubricant, hit of dirt or foreign particles, overloads of the engine, development of corrosion and other adverse effects. Regardless of the defect nature, the reason of its emergence has to be established and eliminated prior to assembly of the engine in order to avoid a recurrence.
3. For survey take inserts from the beds in the block engine cylinders/case, radical and conrod covers and the lower heads of rods. Spread out the removed inserts on a pure plain working surface as their arrangement on the engine that will allow to correlate their state to a condition of the corresponding necks of a bent shaft.
4. Dirt and foreign particles get to the engine in various ways. They can be left after completion of capital repairs as a result of the negligent relation to cleaning performing procedures inside, get via filters or system of ventilation of a case. Often dirt gets at first to motive oil and already together with it gets into bearings. It is worth to remember that in the course of normal wear of the engine metal sawdust is inevitably formed. If after performance of recovery work not to pay due attention to the procedure of cleaning of the engine, in it by all means there will be abrasive particles. Regardless of a way of penetration into the engine, all foreign particles are introduced in a soft surface of a working layer of inserts of bearings of sliding sooner or later and are easily distinguished at visual survey of the last. The largest particles usually do not get stuck tightly in inserts, but deep furrows and teases leave on their working surfaces and surfaces the corresponding necks of a shaft. The best prevention of emergence of this sort of defects is the conscientious attitude to performance of cleaning of the engine after completion of capital repairs and installation in the course of assembly of only absolutely pure components. Also it is worth to remember need of performance of regular and frequent change of motive oil.
5. Oil starvation can be also caused by several reasons which often are closely interconnected with each other. It is necessary to carry the engine overheat (leading to oil fluidifying), overloads (as a result of which oil is forced out from bearings), the oil leak (connected with the excessive size of a working gap in bearings, wear of the oil pump, or excessive increase in turns of the engine), etc. to those. The violation of passability of maslotok most often connected with negligence of installation of components at the assembly conducting to a rassovmeshcheniye of oil openings also causes reduction of supply of oil in bearings and, finally, to an exit of inserts out of operation. A characteristic sign of oil starvation is the wipe and replacement of a soft working layer of inserts from a steel substrate. Sometimes temperature increases to such an extent that on a substrate violet spots are formed.
6. It is necessary to remember that also the driving manner has significant effect on service life of bearings. Increase in load of the engine is promoted by frequent full opening of a butterfly valve, the movement on small turns, etc. Replacement of an oil film from a working gap of bearings results that conducts to a softening of inserts of the last and education on their working surface of small cracks (fatigue deformation). Finally there is a peeling of separate fragments of material of a working layer and their loss from a substrate.
7. Operation of the car in the conditions of a city cycle is often connected with commission of a set of short trips that leads to development of corrosion of bearings as insufficient warming up of the engine promotes loss in it of condensate and formation of chemically aggressive gaseous mixes. Aggressive products accumulate in motive oil, forming slime and acid and as oil continuously comes to bearings, finally influence material of inserts of the last, causing its oxidation and destruction.
8. The wrong installation of inserts at assembly of the engine also conducts to a bystry exit them out of operation. At too dense installation the size of a working gap is inadmissibly reduced that is the reason of oil starvation of bearings. Hit between backs of inserts and beds of bearings of foreign particles leads to formation of sites of an eminence of a working surface of inserts and destruction of the last in the course of normal operation of the engine.
9. Try not to touch working surfaces of inserts fingers as at the same time the risk of casual damage of soft material of a blanket considerably increases and inevitably there is its pollution.
10. As it was already mentioned above in this Section, replacement of inserts at capital repairs of the engine has to be made without fail regardless of their state - the attempt to ignore this requirement is capable to lead only to the seeming economy. |