Mazda 626

1991-1998 of release

Repair and operation of the car

Mazda 626

+ 1. Maintenance instruction
+ 2. Maintenance
- 3. Engines
   + 3.1. Petrol engines (1,6 and 1,8 liters)
   + 3.2. Petrol 4-cylinder engine (2 liters)
   + 3.3. Petrol V6 engine (2,5 liters)
   - 3.4. Partition of engines (1,6 and 1,8 liters)
      3.4.1. Introduction
      3.4.2. Technical characteristics
      3.4.3. Repair work without dismantle of the engine from the car
      + 3.4.4. Capital repairs of the engine
      3.4.5. Checks of the engine
      3.4.6. Removal and installation of the engine
      3.4.7. Preparation for a partition
      3.4.8. Engine partition
      3.4.9. Partition and check of a head of cylinders
      3.4.10. Repair of valves
      3.4.11. Assembly of a head of cylinders
      3.4.12. Removal of pistons and rods
      3.4.13. Removal of a bent shaft
      3.4.14. Check and cleaning of the block of cylinders
      3.4.15. Honingovaniye of cylinders
      3.4.16. Check of pistons and rods
      3.4.17. Check of a bent shaft
      3.4.18. Check of radical bearings and bearings of rods
      3.4.19. Engine assembly order
      3.4.20. Installation of piston rings
      3.4.21. Installation of a bent shaft
      3.4.22. Installation of a back epiploon of a bent shaft
      3.4.23. Installation of pistons and rods
      3.4.24. Launch of the engine after repair and a running in
   + 3.5. Partition of engines (2,0 and 2,5 liters of V6)
   + 3.6. Diesel engine 2,0 liters
   + 3.7. Systems of electric equipment of the engine
+ 4. Heating and ventilation
+ 5. Fuel system
+ 6. Exhaust system
+ 7. Transmissions
+ 8. Coupling and half shafts
+ 9. Brake system
+ 10. Running gear
+ 11. Body
+ 12. Electric equipment
+ 13. Electrical circuitries
+ 14. Useful tips


3.4.18. Check of radical bearings and bearings of rods


Causes of wear of bearings

1. Decrease in strength of metal; fragmentary scratches

2. It is incorrectly put; the bright (polished) strips

3. It is scratched by dirt; dirt ate in the surface of the bearing

4. Lack of oil; the top layer was wiped

5. Excessive wear; the top layer was wiped on all surface

6. The bearing is deformed; the top layer was wiped around

In spite of the fact that radical and conrod bearings at capital repairs of the engine are subject to obligatory replacement, old bearings should be stored in the place of their installation for careful check as wear tracks on these details allow to restore the general condition of the engine.

Insufficient lubricant, presence of dirt and foreign particles, overload of the engine and corrosion are causes of destruction of bearings of a bent shaft.

Irrespective of the reason which caused destruction of bearings it should be eliminated before final assembly of the engine to avoid repeated damages of these details.

When checking bearings they should be got from seats (from the block of cylinders, covers of radical bearings of a bent shaft, conrod covers and rods) and to spread 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 bent shaft in which the bearing underwent the increased wear.

Dirt and foreign particles get to the engine for various reasons - in the course of assembly, via filters or system of ventilation of a case, through oil.

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 a clearing. Irrespective of the origin reason foreign pollution usually take root into soft alloy of the bearing and are easily distinguishable.

Large particles will not be able to take root into the bearing and lead to emergence of scratches and zadir on surfaces as bearing and necks of a bent shaft.

The best way of elimination of the reason of such wear is careful washing of details and maintenance of faultless purity in the course of assembly of the engine. For the prevention of premature wear it is also recommended to a thicket to change oil and filters.

Insufficient lubricant of the engine can be caused by a number of the interconnected reasons. An excessive overheat of the engine (causes oil fluidifying), overloads concern to them (cause expression of oil from the surface of bearings) and pressure decrease because of leak (emission) of oil (because of the raised gaps in bearings, wear of the oil pump, big frequency of rotation of a bent shaft). Also blocking of oil channels, usually owing to a nesovmeshchennost of lubricant openings in the bearing and details of its case is the reason of the accelerated wear of bearings of a bent shaft that causes insufficient lubricant and failure. When insufficient lubricant is a cause of destruction, there is a wipe or expression of material of a covering of the bearing from a steel basis. Temperature increases up to such level that from an overheat there is a vykrashivaniye of a steel basis of the bearing in blue color, the possibility of deformations of covers of bearings and bolts of rods is not excluded.

Durability of bearings of a bent shaft also significantly depends on skills of driving and the nature of movement. Bearings experience the raised strain at the movement with completely open butterfly valve, long driving at small speeds, at pro-slipping. At the raised loadings there is an expression of an oil film, bearings experience flexural deformations at which microcracks (fatigue wear) are formed. As a rule, there is a bearing covering separation from a steel basis in the form of small particles. Trips on small distances can be the reason of corrosion wear of bearings as because of insufficient warming up the condensed moisture and gases causing corrosion do not manage to be removed. These components collect in oil, causing formation of acids and insoluble rainfall. In process of intake of oil to bearings there is their corrosion under the influence of acids, causing their destruction and failure.

Exit of bearings out of operation can be also caused by the wrong installation in process of assembly of the engine. Too dense landing is the reason of an insufficient lubricant gap and bad penetration of lubricant. The dirt and foreign particles which got under the bearing back cause its uneven prileganiye and premature failure.

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