2.5. Replacement of spark plugs
Spark plugs replace at planned maintenance.
If unplanned replacement of spark plugs is necessary, it is necessary to apply only the spark plugs recommended for this engine.
It will allow to prevent failures of the engine, decrease in its power, deterioration in acceleration performance, increase in content of harmful substances in the fulfilled gases and creation of hindrances for radio reception. Especially important characteristics of candles are the quantity of electrodes, kalilny number and in some cases ability not to create hindrances to radio reception.
Normal work of spark plugs – one of the most important conditions of effective operation of the engine. It is necessary to install on the engine only the spark plugs recommended by manufacturer. At the serviceable engine cleaning of spark plugs is carried out seldom.
Petrol V6 engines
Weaken collars and remove the air branch pipe connecting the air filter and the case of throttle knot.
Clear candles a brush, the vacuum cleaner or a stream of compressed air to prevent hit of dirt in engine cylinders after a vyvinchivaniye of spark plugs. Unscrew candles a candle key 3122 B.
Screw in new spark plugs and tighten their moment 30 N · m.
Connect high-voltage wires to spark plugs.
Establish the casing of the engine and an air branch pipe connecting the air filter and the case of throttle knot.
Petrol V8-2V engines
Weaken collars and remove the air branch pipe connecting the air filter and the case of throttle knot.
Unscrew screws and remove an engine casing (see fig. 3.2-3).
Release clamps and disconnect electric sockets from ignition coils.
Clear candles a brush, the vacuum cleaner or a stream of compressed air to prevent hit of dirt in engine cylinders after a vyvinchivaniye of spark plugs. Unscrew candles a candle key 3122 B.
Screw in new spark plugs and tighten their moment 30 N · m.
Check and if necessary replace sealing rings, install coils of ignition and fix them by bolts, having tightened their moment 10 N · m.
Connect electric sockets to ignition coils.
Petrol V8-5V engines
Unscrew screws and remove an engine casing (see fig. 3.2-3).
Left head of the block of cylinders
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Fig. 2-12. An arrangement of electric sockets (1) and bolts (3) fastenings of coils of ignition, and also bolts (2) fastenings of an arm on the left head of the block of cylinders of the petrol V8-5V engine
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Unscrew bolts 2 and remove an arm.
Unscrew bolts 3 fastenings of coils of ignition and remove coils.
Clear candles a brush, the vacuum cleaner or a stream of compressed air to prevent hit of dirt in engine cylinders after a vyvinchivaniye of spark plugs. Unscrew candles a candle key 3122 B.
Screw in new spark plugs and tighten their moment 30 N · m.
Check and if necessary replace sealing rings, install coils of ignition and fix them by bolts, having tightened their moment 10 N · m.
Establish an arm and connect electric sockets to ignition coils.
Right head of the block of cylinders
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Fig. 2-13. An arrangement of electric sockets (1) and bolts (3) fastenings of coils of ignition, and also bolts (2) fastenings of an arm on the right head of the block of cylinders of the petrol V8-5V engine
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Unscrew bolts 2 and remove an arm.
Unscrew bolts 3 fastenings of coils of ignition and remove coils.
Clear candles a brush, the vacuum cleaner or a stream of compressed air to prevent hit of dirt in engine cylinders after a vyvinchivaniye of spark plugs. Unscrew candles a candle key 3122 B.
Screw in new spark plugs and tighten their moment 30 N · m.
Check and if necessary replace sealing rings, install coils of ignition and fix them by bolts, having tightened their moment 10 N · m.
Establish an arm and connect electric sockets to ignition coils.
Check of spark plugs
On appearance of spark plugs it is possible to diagnose a condition of the engine. Pure, white, without raid the insulator of spark plugs testifies to too poor fuel-air mix. It also indicates that a candle too hot (heat from the central electrode is taken away slowly). It is necessary to adjust composition of fuel-air mix or to replace a candle.
Adjournment of a dry soot indicates too rich mix. If the raid black, oily – the engine is worn-out, it needs to be checked and repaired. If the insulator is covered with a light brown raid, then the composition of mix is optimum, and the engine is in good shape.
Too big or too small interelectrode gap at which the spark size changes leads to decrease in overall performance of the engine. The gap has to conform always to technical requirements and is checked by a wire template or the probe. It is possible to modify a gap a podgibaniye of a side electrode the special tool. The central electrode cannot be bent at all as it can lead to breakage of the insulator and an exit of a candle out of operation.
Before installation of a spark plug in the engine check that the carving was pure and intact.
There are two types of the consolidations established in a cylinder head: with a flat saddle and elastic (steel or copper and asbestos) laying or with a conic saddle without laying. At installation of a new candle first of all it is necessary to check what consolidation is provided in a cylinder head, diameter and length of a carving part. If to establish a candle with a long carving part in a head with a short carving, then the acting part of a candle will become covered by a deposit and pitches, lead deposits. The candle will overheat, perhaps oplavleny carvings. At a reversing of such candle it is possible to damage a carving in a cylinder head. At a short carving part of a candle and long – in a head, the deposit and various deposits hammer a carving, there is its oplavleniye. After long work it is necessary to pass a tap a carving part in a cylinder head, but so that dirt did not remain in the cylinder.
The major parameter characterizing a candle is temperature condition of its elements and first of all the central electrode and a surface of a skirt of the insulator. The main problem during creation of a candle for the high-speed engine is implementation of contradictory requirements. On the one hand, it is necessary to provide rather high temperature of a skirt of the insulator that during the long work on small loadings and single to the course to prevent formation on it of the deposit leading to shunting, especially at a low temperature. Upon transition to big loadings at high temperature there is a self-cleaning of the insulator of a candle due to burning out of deposits on it. On the other hand, with a high frequency of rotation and big loading temperature of the central electrode and lower part of the insulator should not exceed the top limit at which there is kalilny ignition (mix ignition even before emergence of a spark from system of ignition). To a cycle ignition comes from a cycle earlier and earlier, temperature of details increases until something does not burn down: at best a candle, in the worst – the piston. So, because of a small candle there can be big troubles.
How to prevent a possibility of emergence of kalilny ignition? First of all it is necessary to watch for correct (according to the instruction) installation of corners of an advancing of ignition, without allowing too early ignition.