Jeep Grand Cherokee

1993-1999 of release

Repair and operation of the car

Jeep Grand Cherokee
+ Cars of the Jeep Grand Cherokee brand
+ Settings and routine maintenance
+ Line six-cylinder engine
+ V8 engine
- Procedures of the general and capital repairs of the engine
   General information
   Capital repairs of the engine - the general information
   Check of compression pressure in cylinders
   The diagnostic checks made by means of the vacuum gage
   Methods of removal of the engine and necessary precautionary measures
   Removal and installation of the engine
   Options of restoration of the engine
   Order of dismantling of the engine
   Dismantling of a head of cylinders
   Cleaning and check of a condition of a head of cylinders
   Service of valves
   Assembly of a head of cylinders
   Removal of conrod and piston assemblies
   Removal of a bent shaft
   Cleaning of the block of the engine
   Check of a condition of the block of the engine
   Honingovaniye of cylinders
   Check of a condition of conrod and piston assemblies
   Check of a condition of a bent shaft
   Check of a condition of radical and conrod bearings
   Engine assembly order after completion of its capital repairs
   Installation of a bent shaft and check of gaps of radical bearings
   Installation of piston rings
   Installation of conrod and piston assemblies and check of gaps in conrod bearings
   The first start of the engine after capital repairs
+ Cooling systems, heating and air conditioning
+ A power supply system and production of the fulfilled gases
+ System of electric equipment of the engine
+ Systems of decrease in toxicity of the fulfilled gases and engine management
+ Manual box of gear shifting
+ Automatic transmission
+ Transfer case
+ Coupling and transmission line
+ Brake system
+ Suspension bracket and steering
+ Body
+ System of onboard electric equipment
+ Governing bodies and methods of operation

Check of a condition of radical and conrod bearings

In spite of the fact that replacement of inserts of radical and conrod bearings by new is made in the course of capital repairs of the engine without fail, the condition of old has to be subjected to the most attentive studying as the analysis of its results can give valuable information on the general condition of the engine.

Typical defects of bearings of a bent shaft.

Exit of bearings out of operation can result from insufficient greasing, hit of foreign particles in them, overloads of the engine and impact of corrosion. Irrespective of character of the reason of an exit of bearings out of operation, it has to be eliminated prior to assembly of the engine in avoidance of a recurrence at operation of the restored unit.

For check of a state, take inserts from covers of radical and conrod bearings, beds in the block of the engine and the lower heads of rods and spread out them on a plain pure surface in the same order in what they were established on the engine. It will allow to connect problems of bearings with a condition of the corresponding necks of a shaft.

Dirt and foreign particles can get to the engine in various ways. They can be left at assembly or get via filters or system of ventilation of a case (PCV), to get to bearings together with oil. Metal sawdust can be left after carrying out machine processing or is produced in the course of normal functioning of the engine. Abrasive particles often remain in the engine after holding recovery procedures, in particular if due attention is not paid to cleaning of the block and internal components. Irrespective of a way of penetration into the engine, foreign particles and dirt as a result most often are introduced in soft material of bearings where can be easily identified. Large particles do not get stuck in bearings, and scar on surfaces of inserts and necks of a shaft. The best preventive measure for prevention of an exit of bearings out of operation is the conscientious attitude to performance of cleaning of the engine and its components after capital repairs with application of the recommended methods of its performance. Important value has also carrying out regular and frequent change of motive oil and an oil filter.

The lack of lubricant (or its termination) can be a consequence of several, often interconnected, the reasons. It is necessary to carry to them: the overheat (leading to thinning of an oil layer), the engine overloads (leading to replacement of an oil layer from gaps in bearings) and withdrawal of oil from gaps of bearings (owing to their too big size, wear of the oil pump or excessively high turns of the engine). Violation of passability of maslotok most of which often results from a rassovmeshcheniye of oil openings of inserts and beds also leads to oil starvation and an exit of bearings out of operation. When the lack of lubricant is the reason of malfunctions of bearings, the soft blanket of inserts is usually forced out from a steel substrate. Sometimes temperature increases to such values that the substrate gets a bluish shade.

Also the driving manner has significant effect on service life of bearings. Full opening of the gate at the movement with small speeds leads to substantial increase of load of bearings that leads to squeezing of an oil film from gaps. Such overloads lead to a strong flexure of inserts and education on them thin cracks (fatigue tension). Over time there is a separation of separate pieces of a soft layer of an insert from a steel substrate. Use of the car for movements of short distances leads to emergence of corrosion of bearings as a result of insufficient warming up of the engine which is the reason of formation of condensate and aggressive gases. These products accumulate in motive oil, forming acids and slime. When such oil gets to bearings, acid begins to corrode their surfaces, leading to material corrosion.

Incorrect installation of bearings in the course of assembly of the engine can also lead to a bystry exit them out of operation. Pulling of bearings is the reason of installation of insufficient size of gaps and, as a result, leads to oil starvation of bearings. Hit between a back of an insert and a bed of the bearing of foreign particles at installation of bearings leads to formation of eminences of a bearing surface that becomes later the bearing exit reason out of operation.