Automotive spark plugs are part of the ignition system, which can be contact (common on older cars) and electronic. In addition to spark plugs providing a spark due to which the piston of a gasoline engine moves, the ignition system (contact) consists of a battery, electric wires of various voltages, a generator, an ignition coil, an interrupter, a distributor, a capacitor and an ignition switch.
Spark plugs play an important role in the operation of the engine, and the slightest malfunction in their functioning affects the power, the engine starts to “triple” (if only three of the four cylinders work), fuel consumption increases, and in some cases there is a possibility of engine detonation. In order to avoid such situations, the replacement of spark plugs should be carried out after a run of approximately 30 thousand kilometers or as necessary.
Most of the machine models found on the Russian market allow you to replace the candles yourself. To do this, in most cars you need to open the engine, remove the air filter, disconnect the ignition with the key. Using a special candle key, you need to unscrew all the candles and inspect them.
A good specimen can be seen right away - it is characterized by the absence of carbon deposits, even, most often brown in color on the "skirt" of the insulator. The presence of soot on the parts does not mean that the replacement of spark plugs will be absolutely necessary. In some cases, this indicates that the engine is running on rich blends, but the oily black finish implies that it is better to change the part. Replacement of spark plugs is necessary if traces of aluminum fusion are found on them or the electrodes are damaged or bent.
For complete confidence in the quality of the operation of the candle, it must be checked on a special tester, a stand equipped with a barometric chamber or a piezo gun for correct spark formation and, if necessary, correct the gap between the additional and the main electrode in accordance with the factory recommendations. A gap of about 1.5 mm is considered optimal, and this value can be reached both by narrowing the gap (by gently tapping on the side electrode) and by expanding it through no less careful bending.
After adjusting the operation of the old one or selecting a new set, the candles are screwed into place, the ignition is connected to them, the filter is installed back, the engine is closed and checked. In an ordinary car, this operation can be done independently somewhere in 15 minutes. Car service masters will do this, of course, faster, and at the same time, a service such as choosing spark plugs is almost always provided. It all depends on the client.
Spark plugs should be replaced on the basis of the characteristics indicated in the technical data sheet of the machine. When changing them, they are either installed exactly the same as indicated in the factory documents, or it is allowed to replace these parts with copies of other manufacturers that have the required characteristics. If the car enthusiast wants the spark plugs to last longer, he can choose options with a side electrode having platinum inserts, or models with several side electrodes (if any).
Important characteristics of the candle when it is selected are as follows: length and diameter of the thread, as well as the glow number. If it is short, combustion products will settle on the thread of the head, and it will be very difficult to subsequently install a normal candle. And if long, then the same elements will settle on the candle, which will lead to the need for engine overhaul. A candle of the wrong diameter will not be easy (impossible) to screw in, and the wrong glowing number will lead to burnout, premature wear of candles, engine failure.