Jeep Grand Cherokee

1993-1999 of release

Repair and car operation

Jeep Grand Cherokee
+ Cars of mark Jeep Grand Cherokee
+ Options and routine maintenance
+ Рядный the six-cylinder engine
+ Engine V8
- Procedure of the general and engine major repairs
   The general information
   Engine major repairs - the general information
   Check компрессионного pressure in cylinders
   The diagnostic checks made by means of the vacuum gauge
   Methods of removal of the engine and necessary safety measures
   Removal and engine installation
   Variants 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
   Assemblage of a head of cylinders
   Removal of shatunno-piston assemblages
   Removal of a cranked shaft
   Cleaning of the block of the engine
   Check of a condition of the block of the engine
   Хонингование cylinders
   Check of a condition of shatunno-piston assemblages
   Check of a condition of a cranked shaft
   Check of a condition radical and шатунных bearings
   Assembly order of the engine after end of its major repairs
   Installation of a cranked shaft and check of backlashes of radical bearings
   Installation of piston rings
   Installation of shatunno-piston assemblages and check of backlashes in шатунных bearings
   The first start of the engine after major repairs
+ Systems of cooling, heating and air conditioning
+ The power supply system and release of the fulfilled gases
+ System of an electric equipment of the engine
+ Systems of decrease in toxicity of the fulfilled gases and engine management
+ Manual box of a gear change
+ Automatic transmission
+ Distributing box
+ Coupling and трансмиссионная a line
+ Brake system
+ Suspension bracket and steering
+ Body
+ System of an onboard electric equipment
+ Controls and operation receptions


Check компрессионного pressure in cylinders

Check компрессионного pressure in cylinders can give the valuable information on the general mechanical condition of the top part of the engine (pistons, piston rings, valves, linings of heads of cylinders). Special value has possibility of that definition, whether are the falling reason компрессионного the pressure of leak caused by deterioration of piston rings or defects of valves and their saddles, or the reason lies in infringement of integrity of a lining or the head case.

For carrying out of the given check the engine should be heated-up to normal working temperature, and the battery is completely charged.


    Begin with cleaning of candle niches (take advantage of compressed air, small or the simple bicycle pump). It will allow to avoid hit in the dust engine at removal of spark plugs. Remove all spark plugs (the Head of Adjustment and routine maintenance). Fix throttle заслонку in completely open position. Disconnect a wire of the coil from the central plug of a cover of the distributor and earth it on the engine case. For a guarantee of qualitative grounding take advantage of a wire equipped from both ends with a clip of type "crocodile". Also it is necessary to put temporarily out of action a contour of the fuel pump (the Head of the Power supply system and release of the fulfilled gases). Establish компрессометр in a candle aperture of the first cylinder.
    It is preferable to use компрессометр not clamping type, and the equipped carving nozzle rolled in a candle aperture.
    Turn the engine, having spent pistons at least through seven steps of compression, reading out instrument readings. Pressure in the cylinder of the serviceable engine should rise quickly. If low pressure upon the first step is accompanied by its gradual lifting during the subsequent, it testifies to an unsuccessful condition of piston rings. Low pressure upon all steps speaks about leaks of valves or defect of a lining of a head of cylinders (the reason presence of cracks in head moulding can be also). Often reason low компрессионного pressure appears superfluous нагарообразование on plates of valves. Write down the maximum indication компрессометра. Repeat measurements for all remained cylinders and compare results to requirements of Specifications. Fill in in each of cylinders through its candle aperture a little (about three teaspoons) impellent oil and repeat check. If oil addition has led to normalisation (increase) компрессионного pressure the reason of its low indications during initial check is deterioration of piston rings. If appreciable increase of pressure it is not observed, leaks of valves or a head lining take place. Leaks of valves can be caused прогаранием their saddles and-or deformation of working surfaces of facets, and also a bend of cores of valves or formation of cracks in plates. If pressure in two next cylinders equally low it is rather strong argument in favour of presence of infringement of integrity of a crosspiece of a lining of a head between them. Will confirm the given assumption cooler presence in chambers of combustion or картере the engine. If pressure in one of cylinders differs from the others approximately on 20 % and it is accompanied by insignificant infringement of stability of turns of idling, it is necessary to check up cams of final valves of a camshaft on presence of signs of deterioration. Unusually high компрессионное pressure speaks about possible strong нагарообразовании in combustion chambers. In this case it is necessary to remove and a head () and to spend it (them) декарбонизацию. Pressure drop or its appreciable difference in different cylinders speaks about necessity of carrying out of check of the engine on leaks in the conditions of a car-care centre workshop. Such test will help to localise a source of leak and to estimate degree of gravity of defect.