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Spark plug

Depending on the purpose, candles have a number of design features. So, for cars and motorcycles, heavy traffic conditions, when possible ingress of water on the engine, and increased requirements to the level of interference, use shielded candles with hermetic sealing high voltage wires. In order to improve the stability of the candles on the case sometimes made several electrodes or side electrodes do not (floating electrode).

Depending on the particular workflow candles made with recessed inside the body with a protruding insulator or an insulator (for combustion chambers with an intensive turbolizatsiey mixture in the combustion chamber).

The most important parameter characterizing a candle, a temperature mode of its elements, and especially of the central electrode and the surface of the insulator. The main problem in creating a spark for the high-speed engine is the implementation of conflicting demands. On the one hand - to provide sufficient heat shed that during prolonged operation at low load and idling to prevent the formation of soot on it, which leads to bypass especially at low temperatures. In the transition to heavy loads at high temperatures the self-cleaning insulator candles burn fat at the expense of it. On the other hand, at high speeds and high load the temperature of the central electrode and the lower part of the insulator should not exceed the upper limit at which there is surface ignition (ignition of the mixture before the spark ignition system). From cycle to cycle ignition occurs earlier and earlier, the temperature rising parts as long as that is not burned - in the best case, a candle, in the worst - the piston. So because of the small candles can be in big trouble.

How to prevent the possibility of pre-ignition? First of all, you need to follow the right (under the instruction) by setting the ignition timing angles, avoiding too early ignition. When the contact system ignition timing can suddenly increase, for example, if one of soldered bounce breaker contacts.

The second condition - always pour gasoline corresponding level forcing the engine (compression ratio, rated speed, content and others.). The lower the octane number, the greater the propensity for surface ignition. Well, if you still flooded with low-octane gasoline, you can not go for heavy loads at high rotational speeds.

The third condition, sometimes the most important thing - to install a candle to the desired heat range in accordance with the recommendations tion engine manufacturer.

The most convenient designation of glow, at one time taken by the majority of European companies by the time (in seconds), after which when tested on a special installation begins surface ignition. In recent years, most companies switched to the symbol glow of candles.

Some practical advice for choice candles and to their service

Install new spark after a short run (about 1,000 km), it is advisable to unscrew them by marking the number of the cylinder, and carefully inspect the condition of insulators. With a correctly heat range and the optimal composition of the mixture and ignition timing angle of the insulator is light brown, brown or light gray. Multi-colored deposits on the insulator and electrodes indicate the presence of fuel or engine oil a large number of additives. Black, matte finish carbon deposits on the insulator, the electrodes and the body - a sign of work in most modes on pereobogaschenie mixture or too high a heat rating. It is necessary to check the adjustment of the carburetor or fuel injection system (eg by gazoanalizato py) or install a hot candle. Shiny black soot indicates contact with the cylinder lubrication through piston rings and valve guides. Requires repair of the engine.

If the insulator "snow-white" color - hence, the candle worked on the maximum permissible thermal conditions. The reasons: too earlier ignition repauperization mix or too "hot" candle for the engine. It is necessary to check the carburetor adjustment, ignition timing characteristics of the machine and, if they are OK, put a cold candle. Well, the next degree of overheating candles - candles melted electrodes (well that is not burned-out bottom of the piston).

Sometimes it may be that all the candles of the same brand in different cylinders have insulators different in color. The reasons can be several. Typically, gasoline engines mixture (composition) and anti-knock additive in the cylinders evenly distributed.

There are various quantities of engine compression ratio for each of the cylinders. Well, between the engines of the same model is sometimes different compression ratio for the whole unit. Due to departures from processes, materials, and others. Among the candles of the same brand as there is a large variation in the actual heat rating. When a large difference in the condition of the spark sometimes have even installed one engine candles with different heat range. To always have a supply of heat rating in different operating conditions, it is advisable to have two sets of candles and set cooler in the summer and in the winter "hot".

Recently, a number of companies produce candles with advanced thermal field candles. For this, the central electrode is made of copper, is coated on top of the heat-resistant material (nickel, chromium). Sometimes the side electrodes are made of metal with good thermal conductivity and heat resistant coating. Other original decision is manufacturing miniature platinum center electrode, does not protrude from the insulator. Particularly cold candle to heat range of 300 and above for uprated engines (with turbonadduovm, stroke, etc.) Are usually made with a silver electrode of small diameter and a short skirt insulator. Before setting such candles, sometimes it is recommended to warm up the engine on hot candlelight and then install the cold.

It must be borne in mind that in the purification of the candles in the sandblasted surface of the insulator is destroyed. It is better, turning a candle, pour into the body, the solvent, benzene, or apply a special spray can. Then a wooden stick to clear an insulator and blow it with compressed air.