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Check of kompressionny pressure, assessment of a condition of cylinders
Check of kompressionny pressure, assessment of a condition of cylinders
Check of kompressionny pressure
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For performance of procedure of check of kompressionny pressure the help of the assistant is required. |
Measurement of kompressionny pressure allows to make general idea about current state of such internal components of the engine, as laying of a head of cylinders, elements of the klapanny mechanism, pistons and piston rings. The analysis of results of check allows to define, whether the engine needs major regenerative maintenance, or it is rather simple to replace sealing laying of a head. Measurement is made with the help компрессометра.
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For diesel engines it is necessary компрессометр with a limit of measurements approximately to the 40th bar. |
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Warm up the engine to normal working temperature (about 80°С), make sure of completeness of a charge of the storage battery.
Muffle the engine and allow a final collector to cool down within about 10 minutes.
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Petrol models
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Remove a decorative cover of the engine and disconnect VV electroconducting from spark plugs.
Serially turn out spark plugs, - before a reversing of a candle blow its niche the compressed air (it is possible to use the bicycle pump) for the purpose of minimization of risk of hit of garbage in cylinders.
Having used a clamping or carving nozzle, connect компрессометр to a candle opening of the first cylinder.
Ask the assistant against the stop having squeezed out a gas pedal, completely to open a butterfly valve 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 kompressionny pressure in the remained cylinders.
Muffle the engine, disconnect компрессометр, screw spark plugs and establish into place a decorative cover of the power unit.
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Diesel models
All models
Compare results of measurement by requirements of Specifications of Head the Engine.
The most admissible difference of pressure in separate cylinders can make 1.5
kgfs/cm2 for petrol engines and 3.0 kgfs/cm2 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, indicates wear of piston rings. If pressure does not increase with repetition of cycles, it is necessary to check tightness of closing of valves and integrity of a head of cylinders (the probability of existence of cracks in a head is not excluded also).
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Nagaroobrazovaniye on plates of valves also can lead to decrease in kompressionny 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 opening a teaspoon of impellent oil and repeat check. If addition of oil leads to temporary restoration of a compression, the reason of its decrease, most likely, is wear of the piston, piston rings or cylinder walls. If the increase in a compression did not occur, it is possible to draw a conclusion on violation of tightness of closing of valves or damage sealing laying/moulding of a head of cylinders.
The low compression in two next cylinders with high degree of probability is identical points to violation of integrity of sealing laying of a head around a crossing point between cylinders. Presence of cooling liquid at chambers a combustion/case of the engine can serve as confirmation to this assumption.
If the compression in one of cylinders approximately for 20 % is lower, than in the others, and violation of stability of turns of idling at the same time takes place, it is necessary to estimate degree of wear of working ledges of the corresponding cams of a camshaft.
Check of tightness of cylinders
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During this check tightness of cylinders (till speed of production of the compressed air pumped in them) is estimated and, - in case of its violation, - sources of leaks are localized. This check is alternative to check of kompressionny pressure, and from a certain point of view is much more effective than the last as visually to reveal a source of leak simpler, than to do theoretical conclusions according to indirect data.
Warm up the engine to normal working temperature (80°С), then muffle it.
Uncover a broad tank of system of cooling (see. Head Current leaving and service).
Remove a decorative cover of the power unit and turn out ignition/incandescence candles.
Turning the engine for the central bolt of a cranked shaft in the normal direction, bring the piston of the cylinder subject to check into the provision VMT of the end of a step of compression, then connect to the corresponding candle opening a special tester, previously having made its calibration, - act in strict accordance with instructions enclosed to the device.
Uncover a jellied mouth of impellent oil (see. Head Current leaving and service).
Submit to the cylinder the compressed air and according to indications of a measuring instrument estimate speed of dumping of pressure. Result write down.
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If during check the cranked shaft starts to be turned, take care of its blocking. |
Repeat check for the remained cylinders, - act as ignition (see. Head of System of electric equipment of the engine).
Disconnect a measuring instrument, screw candles of an ignition/incandescence and establish into place a decorative cover of the engine.
Compare results of check with requirements of Specifications of Head the Engine. In case of need make necessary regenerative repair.
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Check of a condition of mirrors of cylinders by means of a special lamp sampler
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Remove a decorative cover of the engine and turn out ignition/incandescence candles.
Turning the engine in the normal direction for the central bolt of a cranked shaft, bring the subject piston to cylinder check into situation NMT.
Operating strictly according to instructions of manufacturers, connect a special lamp sampler, fill its flexible light guide in the corresponding candle opening and make a visual assessment of a condition of walls of the cylinder which should have an opaque shade without traces of a honingovochny notch.
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.
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