The quality of the candles can be seen from a car of its type electrodes and thermal insulator cone. If the cone is covered with black candles wet oily sludge, then it is a clear sign that the candle is too cold for that engine. The same could also indicate worn piston rings and cylinder, or it indicates a very high level of oil in the crankcase. Availability, dry carbon black is a result of very long work the engine at idle or during regular driving at low speed and low load vehicle. If the insulator cone candle is clean, completely dry, almost white, with traces of partial melting that it may mean that this candle is too hot for the engine or put up too early ignition. In a normally operating candle color facility should be from light gray to light brown. Nagar has almost absent. Candles need regular cleaning and adjustment of the gap between the electrodes.
During the intensive use of the vehicle the operation should be performed every 10 thousand miles. In the case where annual mileage is less than 10 thousand kilometers, clean and adjust spark gap preferably twice a year, just before the start of summer and winter operating season. To clean the candles are prohibited use sharp metal objects, this is due to the fact that they are easily damaged or scratched insulator on the spark. Scratched on the cone of the insulator begins to increase carbon formation, carbon deposits, in turn, begins to bridge the electrodes, in the end, the candle does not work. There is a belief that is passed down from generation to generation, the essence of this belief lies in the fact that the electrodes must be cleaned candles supposedly open flame. Typically, such actions are deplorable outcome. First, the candle held a similar process, usually out of order. Second, this situation can have serious consequences, which manifest themselves in that the candle is due to overheating becomes latent defect, it just starts to work then, no, and the apparent reason for this is not.
The best way to clean candle is a chemical process which is following. Candles defatted with petrol and dried thoroughly, then put them into hot 20% aqueous ammonium acetate, and kept them there for 30 minutes, the temperature of the solution at this time should not be below 90 degrees. After that, the candles carefully cleans hard nylon brush, thoroughly washed with hot water and dried. All this work should be carried out in the open air, due to the fact that a hot solution of vapors acetic acid. The gap between the electrodes is controlled by candles podgibaniya ground electrode to measure the gap should be used not flat, but cylindrical probe. This is due to the fact that as a result of wear and tear ground electrode is formed recess, so flat probe measurement can not give the correct result.