How to choose spark plugs for the car?

The importance of spark plugs

The spark plug is a consumable item. The wrong or wrong choice of this simple part can lead to serious engine repairs. However, if the driver forgets about it, then the candle will remind of itself. Difficulty starting, unstable engine operation, reduced power, increased fuel consumption. Of course, the cause of all these troubles may not be candles, but first of all it is necessary to check them. When the engine is running, the spark plug heats up. At low loads, in order to avoid the formation of soot, the candle must be heated to a temperature of at least 400-500 ° C. This ensures its self-cleaning. At high loads, the heating should not exceed 1000 ° C. Otherwise, the cylinder may catch fire. Ignition ignition is the ignition of the combustible mixture in the cylinder not by a spark, but by the luminous electrodes of a spark plug.

Candle selection

If the spark plug operates within the specified temperature range, then this is “normal” for the engine. If the spark plug does not reach the self-cleaning temperature, it is "cold" for that engine. When a spark plug is heated above 1000°C during operation, it is considered “hot” for that engine. Is it always necessary to put "normal" spark plugs on an engine? No, this rule can be overridden under certain circumstances. For example: In cold winter you use your car for short short trips. In this case, you can use "hotter" plugs, which will quickly go into self-cleaning mode. By the way, in order to prevent the formation of carbon deposits on spark plugs, it is not recommended to warm up the engine at idle for a long time in winter. After a short warm-up, it is much better to start and continue the warm-up with a light load.

Candle selection for tasks

If the car is often used under heavy loads (motorsport), it makes sense to replace the "normal" spark plugs with cooler ones. Reliable sparking is the main requirement for candles. Why does it depend? Mainly by the size of the electrodes and the size of the gap between them. The theory says that: firstly, the thinner the electrode, the greater the electric field strength; secondly, the larger the gap, the greater the force of the spark. Why, then, in the vast majority of candles, the central electrode is rather “thick” - 2,5 mm in diameter? The fact is that thin electrodes made of chromium-nickel alloy “burn” faster and such a candle will not last long. Therefore, the core of the central electrode is made of copper and coated with nickel. Since copper has a higher thermal conductivity, the electrode heats up less - thermal erosion and the risk of ignition are reduced. Candles with several side electrodes help to slightly increase the resource.

Selection of candles with side electrodes

When one of them burns, the next takes effect. It is true that such a “reserve” makes access to the combustible mixture difficult. Electrode candles coated with a layer of refractory metal (platinum, iridium) help radically improve the situation. This technology allows you to reduce the diameter of the electrode to 0,4-0,6 mm! In addition, he does not overlap the insulator, but blushes with it. Thus, the contact zone with hot gases is significantly reduced, the central electrode is heated less, which prevents ignition from the glow. Such a candle is more expensive, but lasts longer. The resource and price of candles at the same time increase sharply (several times). Spark plug gaps, as everyone knows, should be set in accordance with the recommendations of the engine manufacturer. And what will happen if the abyss changes?

Candle selection and clearance

It has been experimentally proven that “ordinary” spark plugs are painfully sensitive to both a decrease and an increase in the gap - the intensity of the spark decreases, and the likelihood of incorrect ignition increases. The opposite picture is with spark plugs with a thin electrode - they practically do not react to a change in the gap, the spark remains powerful and stable. In this case, the electrodes of the candle gradually burn out, increasing the gap. This means that over time, spark formation will deteriorate in a "normal" plug, and is unlikely to change in a "thin electrode"! If you buy a spark plug recommended by the motorcycle manufacturer, then there are no questions. And if you need to choose an analogue? There are many offers on the market. Why not make a mistake? First of all, take an interest in the thermal number.

Choosing the Right Candle Configuration

The problem is that different companies have different labels. Therefore, the specific car models for which spark plugs are intended are usually indicated on the packaging. Then pay attention to the length of the protrusion of the thermal cone, the length of the threaded part, the sealing method (cone or ring), the size of the hexagon for the spark plug - all these parameters must correspond to the data of the “native” candle. And what is the resource of candles? On average, ordinary candles are enough for 30 thousand km. Spark plugs with a nickel-plated copper center electrode can last up to 50 km. In some candles, the side electrode is also made of copper. Well, the life of spark plugs with platinum-coated electrodes can reach 100 thousand km! However, it should be understood that these figures are for ideal working conditions.

Candle selection and service life

And since the spark plug is a fragile product, such as mechanical damage due to a fall, using low-quality “crack-free” motor oil in gasoline will greatly shorten its “life”. In general - do not save on spark plugs, change them in a timely manner. It will be useful to always have a spare set in the car. How to protect yourself from fake candles. There are many offers on the automotive spark plug market. Bright packaging, shiny metal cases, snow-white insulators, inscriptions in English, dozens of brands - why not get confused by an ordinary motorist! What are the signs to sift tin and choose a quality product? First of all, do not just focus on costs. If a company manufactures a counterfeit, don't assume that the people there are so conscientious that they will surely charge their product below the original price.

Candle selection and appearance

Poor quality of the packaging, which falls apart after opening, fuzzy, muddy inscriptions - 100% a sign of a fake. Crooked, blurry inscriptions on the insulator and the body of the candle will also say the same. We do not hesitate to leave such a product aside. If the first visual test is passed, we move on to the second - the study of the geometry of the candle electrodes. To extend the service life and reduce the heating temperature, make a side electrode with a cross section of at least 3 mm². Look at the length of the side electrode: it should completely cover the center electrode. Check the alignment of the electrodes: they must be exactly on top of each other. Evaluate the quality of soldering the side electrode - all spark plugs in the kit must be the same. We do not buy something asymmetrical, crooked and oblique. Next, we evaluate the quality of the ceramic insulator. It must be whole.

A selection of candles. Fakes

If, upon closer examination, it turns out that it is glued from two halves, this is a fake. Look at the insulator in reflected light. To protect it from contamination, it is covered with a layer of special glaze, which is homogeneous in relation to the branded product. If you see that there are matte spots, then the candle is fake. Renowned corrosion protection companies coat spark plug bodies with a layer of nickel. Zinc coating is used to produce cheap fakes. Nickel - shiny, zinc - matte. Sealing washers that fall when shaking the candle, crookedly twisted tips are also a sure sign of a fake. Once we are done with the visual quality assessment, we move on to the instrumental one. All we need is a set of gauges and an ohmmeter. With the help of a probe, of course, we measure the gaps between the electrodes - after all, all the spark plugs in the kit must be the same.

A selection of candles. Ohmmeter

If you find a spread of more than 0,1 mm, it is better not to mess with such products. Using an ohmmeter, check the resistance of all spark plugs in the kit. With a noise suppression resistor, the allowable range is 10 to 15%. Well, the last check is right on the car, as the spark plug is unscrewed. Start the engine. If the candle is good, the spark should be white or bluish, there should be no passages. If the spark is reddish or there are gaps in the spark, we are dealing with an open marriage. These simple tips may not give a 100% guarantee when buying a low-quality product, but they will protect you from an obvious fake.

Questions and answers:

How to choose the right spark plug for your car? First of all, you need to focus on the electrode gap - it should be within the limits recommended by the car manufacturer. It is easier for a spark to form between thin electrodes.

What are the best spark plugs? Candles from such manufacturers are popular: NGK, BERU, Denzo, Brisk, Bosch. Their products include both high-performance and low-cost options for conventional vehicles.

How do you know which candles to put? It is necessary to rely on the following criteria: dimensions and dimensions of the thread, type of body, heat rating, spark gap, thermal performance, number of electrodes, electrode material.

What kind of candles are put on the engine? First of all, you need to rely on the manufacturer's recommendations. The most expensive option is not always the best. The type of plug depends on the fuel used and the operating conditions.