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Check компрессионного pressure, an estimation of a condition of cylinders
Check компрессионного pressure
For performance of procedure of check компрессионного pressure the help of the assistant is required.
Gauging компрессионного pressure allows to make general idea about a current condition of such internal components of the engine, as a lining of a head of cylinders, elements клапанного the mechanism, pistons and piston rings. The analysis of results of check allows to define, whether the engine requires capital regenerative repair, or simply enough to replace a sealing lining of a head. Measurement is made with the help компрессометра.
For diesel engines it is necessary компрессометр with a limit of measurements approximately to 40 bar.
Warm up the engine to normal working temperature (an order 80С), make sure of completeness of a charge of the storage battery.
Muffle the engine and allow a final collector to cool down during an order of 10 minutes.
Remove a decorative cover of the engine and disconnect ВВ electroconducting from spark plugs.
Serially turn out spark plugs, - before a candle reversing blow its niche the compressed air (it is possible to take advantage of the bicycle pump) for the purpose of minimisation of risk of hit of dust in cylinders.
Having taken advantage of a clamping or carving nozzle, connect компрессометр to a candle aperture of the first cylinder.
Ask the assistant against the stop having squeezed out a gas pedal, completely to open throttle заслонку and to turn the engine a starter on 7-8 turns. Consider the maximum indication of a measuring instrument, write down result.
Operating in a similar manner, measure компрессионное pressure in the remained cylinders.
Muffle the engine, disconnect компрессометр, screw spark plugs and establish into place a decorative cover of the power unit.
Compare results of measurement by requirements of Specifications of the Head the Engine.
As much as possible admissible difference of pressure in separate cylinders can make 1.5 кГс/см2 for petrol engines and 3.0 кГс/см2 for the diesel.
The compression grows in the serviceable engine very quickly. The low value shown after the first cycle, increasing with the subsequent cycles, specifies in deterioration of piston rings. If pressure does not increase with repetition of cycles, it is necessary to check up tightness of closing of valves and integrity of a head of cylinders (the probability of presence of cracks in a head is not excluded also).
Нагарообразование on plates of valves also can lead to decrease компрессионного pressure.
It is necessary to mean that because of different speed of rotation of a starter the received results on different cars can vary slightly, however indications for all cylinders of one engine should be approximately identical.
If pressure is in any cylinder at level minimum or below admissible, try to pour in in the cylinder through a candle aperture a teaspoon of impellent oil and repeat check. If oil addition leads to time restoration of a compression, the reason of its decrease, most likely, is deterioration of the piston, piston rings or cylinder walls. If the compression increase has not occurred, it is possible to draw a conclusion on infringement of tightness of closing of valves or damage of a sealing lining/moulding of a head of cylinders.
The low compression in two next cylinders with high degree of probability is identical specifies in infringement of integrity of a sealing lining of a head around a crosspiece between cylinders. Presence of a cooling liquid at chambers of combustion/kartere of the engine can serve as acknowledgement to the given assumption.
If the compression in one of cylinders approximately on 20 % more low, than in the others, and simultaneously takes place infringement of stability of turns of idling, it is necessary to estimate degree of deterioration of working ledges of corresponding cams of a camshaft.
Check of tightness of cylinders
During the given check tightness of cylinders (on speed of release закачанного in them of the compressed air) is estimated and, - in case of its infringement, - sources of leaks are localised. The given check is alternative to check компрессионного pressure, and from the certain point of view is much more effective than last as visually to reveal a source of leak easier, than to do theoretical conclusions under the indirect data.
Warm up the engine to normal working temperature (80С), then muffle it.
Uncover a broad tank of system of cooling (Current leaving and service see the Head).
Remove a decorative cover of the power unit and turn out ignition/nakalivanija candles.
Turning the engine for the central bolt of a cranked shaft in a normal direction, result the piston of the cylinder subject to check in position ВМТ of the end of a step of compression, then connect to corresponding candle aperture a special tester, preliminary having made its calibration, - operate in strict conformity with instructions applied on the device.
Uncover a jellied mouth of impellent oil (Current leaving and service see the Head).
Submit to the cylinder the compressed air and under measuring instrument indications estimate speed of dump of pressure. Result write down.
If during check the cranked shaft starts to be turned, take care of its blocking.
Repeat check for the remained cylinders, - operate as ignition (see the Head of System of an electric equipment of the engine).
Disconnect a measuring instrument, screw candles of ignition/nakalivanija and establish into place a decorative cover of the engine.
Compare results of check with requirements of Specifications of the Head the Engine. In case of need make necessary regenerative repair.
Check of a condition of mirrors of cylinders by means of a special lamp-sampler
Remove a decorative cover of the engine and turn out ignition/nakalivanija candles.
Turning the engine in a normal direction for the central bolt of a cranked shaft, result the piston of the cylinder subject to check in position НМТ.
Operating strictly according to instructions of manufacturers, connect a special lamp-sampler, fill its flexible optical path in a corresponding candle aperture and make a visual estimation of a condition of walls of the cylinder which should have a matte shade without traces хонинговочной notches.
Operating in a similar manner, examine walls of the remained cylinders (as ignition).
In case of need remove the engine, a head of cylinders and make more detailed direct survey of mirrors of cylinders and necessary regenerative repair.