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2-2-3-proverka-stepeni-szhatiya.html
2.2.3. Check of extent of compression Check of extent of compression shows, what mechanical condition of the top level of the engine (pistons, rings, valves, head laying). In particular, check can show that extent of compression is lowered because of the leak caused by wear of piston rings, defective valves and saddles or because of the burned-through laying of a head of the block.
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At this check the engine should be heated-up to normal working temperature, and the storage battery - completely |
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- Before removal of spark plugs clear area round them (it is necessary to apply if it is available, the compressed air, differently it is possible to use the bicycle pump or a small brush). The purpose consists in that at check not to allow hit in dirt cylinders.
- Remove from the engine all spark plugs (look Head Routine maintenance of the car).
- Block a butterfly valve in completely open situation or let the assistant holds a pedal in the pressed situation.
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- On carburetor models disconnect from the ignition coil a wire of a low voltage. On models with injection of fuel disconnect the fuel pump and an ignition chain, having removed the main relay (it is specified by an arrow).
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- It is necessary for prevention of ignition of fuel which could be injected into an impellent compartment. Usually main relay is located under a cowl near the panel of safety locks, however for exact definition of an arrangement on your model address to Head System of onboard electric equipment.
- Establish in a candle No. 1 opening компрессометр (the cylinder No. 1 is located from a radiator).
- Starter turn the engine, at least, on seven steps of compression and watch compressor indications. On the serviceable engine extent of compression will quickly increase. Low extent of compression in the first step with gradual increase in the subsequent steps testifies to wear of piston rings. Low extent of compression in the first step, not increasing in the subsequent steps, indicates leaks in valves or on прогар laying of a head of cylinders (the crack in a head of cylinders also can be to it the reason). The deposit on internal surfaces of heads of valves also can cause low extent of compression. Write down the greatest measured value.
- Repeat operation for other cylinders and compare results to values of extent of compression in the Size table and adjusting data at the end of the Management.
- If extent of compression low, fill in through openings for spark plugs in each cylinder a small amount of impellent oil (having pressed, about, three times a butterdish of plunzherny type) and repeat check.
- If after oil addition extent of compression increased, piston rings are definitely worn-out. If extent of compression considerably did not increase, in valves or through laying of a head of cylinders there is a leak. Leak in valves can be caused by an obgoraniye of saddles of valves and/or facets, and also a curvature of valves and existence of cracks and dents.
- If two next cylinders have equally low extent of compression, it is quite probable that laying of a head of cylinders between them burned through. Cooler existence in chambers of combustion or a case will confirm this offer.
- If extent of compression in one of cylinders for 20 % is lower, than in the others, and the engine idling works slightly roughly; that the final cam of a camshaft is probably worn-out.
- If extent of compression is unusually high, combustion chambers, possibly, are covered with a deposit.
- In this case it is necessary to remove a head of cylinders and to remove a deposit.
- If extent of compression is lower than norm or strongly differs between cylinders, it is useful to carry out diagnostics of leaks in a repair truck. This check will precisely indicate the reason of leaks and its degree.
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