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Spark plug
general description Spark plug comprises a central electrode with the insulator body and the electrode (s) weight. Between the central electrode and the electrode weight slips spark ignites the fuel-air mixture. Do not use spark plugs other than those recommended. The recommended type of spark is determined, among other things heat range. Heat range characterizes the degree of heat stress candles. The lower heat rating candles, the higher the degree of thermal loading. This candle is better heat dissipation, eliminating the possibility of pre-ignition of the fuel mixture. Candle with high thermal characteristic has the disadvantage that its temperature is higher than the self-purification. It is more prone to fouling, in particular when the engine during operation often does not reach its operating temperature, for example in city traffic, the short travel in winter. The correct number of candles glow is determined by the vehicle manufacturer. There candle with one or more mass electrodes with different thread length and its diameter. When replacing the spark you need to install only the candles corresponding to the requirements of the vehicle manufacturer. Average life of the candle is different. This important role is also played by the electrode material. Chromium-Nickel has a very high thermal conductivity and high corrosion resistance. The best heat sink has a silver and platinum electrodes have high corrosion resistance and resistance to erosion. Lifetime candles lying between 20 000 and 100 000 km, depending on the electrode material and their number. Depending on the engine design, two types of sealing between the spark plug and the cylinder head. Flat seal has an outer sealing ring which is not lost and is fixed to the plug body. When cone seal, no additional sealing elements. With limited space for installation, in most cases, used candles with a flat landing surface and the small size of the key. Candles with a conical seat surface due to compact design are smaller. Spark plugs should be changed strictly according to the schedule of routine maintenance of the car (see chap. Current care and maintenance). In appearance, the candle can be concluded about the candle, quality management and the mixture state of the engine (pistons, piston rings, etc.). Coal deposits  | Symptoms: The presence of soot indicates pereobogaschenie air-fuel mixture or low intensity spark. It causes misfiring complicates start and leads to instability of the engine.
Recommendation: Check whether the air cleaner is not blocked is not too high fuel level in the float chamber, if not jammed choke and not too worn contacts. Try to use candles with longer insulator that raises resistance to contamination. |
Oiling  | Symptoms: oily contamination spark causes wear stem seals. The oil enters the combustion chamber through the valve guides or worn piston ring. It causes misfiring complicates start and leads to instability of the engine.
Recommendation: Perform mechanical recovery work and replace candles. |
Overheat  | Symptoms: Porous, white insulator, erosion of electrodes and the absence of any deposits. It leads to a reduction in the life of the candle.
Recommendation: Check whether the requirements of the Specifications glow of candles set the number is correctly exposed ignition timing is not served there too lean air-fuel mixture leaks vacuum inlet pipeline and whether valves are jammed. Check the coolant level as well, and blockage in the radiator. |
Too early ignition  |
Symptoms: Electrodes are melted. The insulator is white, but may be contaminated due to a misfire, or falling into the combustion chamber of foreign particles. It may lead to engine damage.
Recommendation: Check the number of installed glow of candles, the ignition timing, the quality of the mixture (not too depleted), blockage in the cooling system is functioning normally and the lubrication system. |
Electrically conductive gloss  | Symptoms: Insulator has yellowish color and the polished look. It speaks about sudden rise in temperature in the combustion chambers at sharp acceleration. Ordinary deposits while melted, getting kind of lacquer. It leads to misfire at high speeds.
Recommendations: Change candles (colder, while maintaining the driving style). |
The closure of the electrodes  | Symptoms: Waste combustion products enter the inter-electrode space. Solid deposits accumulate, forming a bridge between the electrodes. Leads to failure of the ignition cylinder.
Recommendation: Remove deposits from the electrode area. |
The normal state of candles  | Symptoms: Gray-brown color and easy deterioration of electrodes. Heat range spark for the type of engine and its general condition.
Recommendations: At replacement of candles set the candles of the same type. |
Peploobrazovanie  | Symptoms: Soft brownish deposits on one or both of the spark plug electrodes. The source of their formation are applied additives to oil and / or fuel. Excessive accumulation can lead to isolation of the electrodes and cause misfiring and unstable engine performance during acceleration.
Recommendation: With the rapid accumulation of sediment change stem seals that will prevent oil from entering the combustion chamber. Try to change the brand of fuel. |
Wear  | Symptoms: Rounding electrodes with a small accumulation of deposits on the working end. Color normal. It leads to difficulty starting the engine in cold damp weather and increased fuel consumption.
Recommendations: Change candles on new, the same type. |
Detonation  | Symptoms: Insulators can be cleaved or cracked. It can cause damage to the insulator as sloppy technique adjustment of a candle backlash. It can cause damage to the pistons. |
Splashing  | Symptoms: After misfire for a long period of time deposits can disintegrating maintaining the operating temperature in the combustion chamber. At high speeds of deposition flakes come off the piston and stick to a hot insulator, causing misfiring.
Recommendations: Replace candles or smooth out and replace the old ones. |
Mechanical damage  | Symptoms may be caused by the ingress of foreign material into the combustion chamber, or occur when the piston stroke about too long candle. Lead to refusal of functioning of the cylinder and piston damage.
Recommendation: Remove from the engine extraneous particles and / or replace
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When screwing candles next does not exceed specified in the Specifications limit the allowable effort.
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