The s myths about spark plugs that you should stop believingpark plugs in a gasoline engine are one of the main elements of the ignition system. They are designed to ignite the fuel-air mixture. In addition, by them you can determine the condition of the “health” of the power unit. The spark plugs have a very simple device, and therefore it is almost impossible to improve anything in them. But marketers have to work, so they come up with advertising “tricks”, making us believe that the candles offered by a particular company are special and the best. For example, they talk about increased vehicle power, improved dynamics, reduced fuel consumption, etc.
Myth #1: The more electrodes in plugs, the more power the engine has
Some manufacturers offer spark plug models with two or more side electrodes (two to four). They supposedly contribute to a more efficient ignition of the fuel-air mixture. Because of this, the engine power increases. But in fact, the spark hits only one electrode, so the engine output does not increase. So this is just an advertising trick.
However, to the manufacturers’ credit, it should be noted that parts with two or more electrodes are more durable than those with one. If more soot appeared on one electrode, the other electrode is put to work. So, due to the additional electrodes, the reliability of spark formation increases. The same can be said about plugs with special slots on the center or side electrodes. Such a solution does not increase the number of sparks, but increases the service life of the consumable.
Multielectrode models have a number of disadvantages:
- due to the additional side electrodes, the access of the fuel-air mixture to the area of spark formation is impaired, and the efficiency of mixture ignition is reduced;
- the flame does not spread well in the combustion chamber;
- insufficient cooling leads to poor combustion of the air-fuel mixture and accumulation of carbon deposits.
If you really need multi- spark plugs, choose the ones with several circular belts on the insulator. The sparks alternately run through them at such a high rate that three sparks are produced in each duty cycle. But be prepared to pay 10 times more for consumables with such design than for standard ones.
Myth #2: You have to change spark plugs every 10,000 miles
This is true if we are talking about regular cleaning, during which the gap between the electrodes is adjusted in parallel. It’s really advisable to do this every 10,000 km. Another option is twice a year: in spring and in autumn.
And in general the candles with chrome-nickel electrodes last for 20 thousand km run, and with a covering of platinum or iridium – all 100 thousand km. But these figures are true only if your vehicle’s engine is in full working order. The period may be shortened due to aggressive driving style and usage of low-quality gasoline.
Do not clean the plugs with metal objects, as they can scratch or damage the insulator cone. Scratches contribute to a faster and stronger formation of carbon deposits. Electrode shunting then occurs and the spark plug fails.
Adjusting the electrode gap is done by bending the side electrode. This is best done with a cylindrical stylus or a piece of wire of appropriate thickness. If you use a flat dipstick, the result will not be correct if it gets into the notch on the side electrode of the plug.
Most often, these consumables stop working because they are contaminated by products of incomplete combustion. The second reason is that when the electrodes are worn, the spark gap increases.
Myth #3: If the threads fit, the spark plug can be installed on any engine
Diameter and thread length are not the only parameters of spark plugs. No less important characteristic is the caliber number. Every engine operates in its own temperature regime, accordingly, the spark plugs should be selected with the optimal glow number. If it is too high, i.e. the spark plug is too hot, the engine will overheat.
If the spark plug is too cold, it cannot clean itself, and so the soot will build up on it. This leads to poor spark formation, reduced engine power and faster wear of the spark plug itself.
And now about the thread on the spark plug. If its pitch and diameter do not correspond to a particular engine, then you simply will not be able to install the element normally! You can, of course, try, but the following will happen:
- a short spark plug – the electrodes will not stand correctly in the combustion chamber, this will lead to unstable operation of the power plant;
- a long spark plug – will interfere with valve or piston movements, it can cause serious failures.
Myth #4: plugs with a tapered resonator around the center electrode reduce fuel consumption
This is another advertising trick. Manufacturers and sellers assure that the tapered resonator forms a flare, that is, a directional effect. This helps reduce gasoline consumption. Additional bonuses are: longer service life of the spark plugs up to 100 thousand km and increased engine output (you can’t do without it!).
In fact, the process of ignition of the fuel-air mixture in the cylinder is a vortex flash, and it can have no direction. Any devices will not help in this.
Being tempted by salesmen, some car owners buy such plugs, and it seems to them that the fuel consumption really goes down. However, according to experts, it is only a self-influence. In fact, it’s all about the fact that you just installed new plugs, regardless of whether they are standard or innovative.
Myth #5: spark plugs with expensive metal coatings increase torque
Put the plugs with tungsten, iridium or palladium coatings and your “swallow” will “fly”! So manufacturers of such parts declare. In fact the spark in such plugs is really more stable, but the torque has absolutely nothing to do with it. Expensive coatings again increase a service life of plugs (it was mentioned above), but it does not influence performance and other qualities of the car.
Myth #6: Iridium or platinum spark plugs are eternal
Some motorists think that one should forget about them at all after buying spark plugs with a covering of expensive metals. Allegedly they serve forever and are not subject to replacement. In fact such candles also have a service life, but it is five times longer than that of standard ones. According to the manufacturers’ statement, the plugs with platinum or iridium coating should easily go over 100 thousand km. But in our operating conditions they can not withstand this life, and in 50 thousand km maximum they need to be replaced.
Besides, the engine output does not increase with the use of yttrium, tungsten, platinum, iridium and palladium spark plugs, contrary to the manufacturers assurances. It remains the same as with conventional copper or chromium-nickel spark plugs.
Still, such candles are better. Platinum is a metal that wears very slowly. The electrodes in spark plugs can be entirely platinum, or they can be laser-soldered with the thinnest pads of this noble metal. If there is erosion in such models, it occurs only in the end parts of the electrodes. The platinum electrode is usually thinner than the usual one, which makes the flame front slightly wider.
Iridium and yttrium plugs are slightly cheaper. This is because they are easier to manufacture. The precious metals in the electrodes provide them with a stable geometry and make the consumables more durable. Such parts are not subject to electrical erosion. The edges of the electrodes do not blunt, the gap does not change, and the spark formation does not lose stability. Such plugs allow designers to freely layout the powertrain and its components.
Myth #7: Plasma spark plugs are the best
Plasma spark plugs are offered for a very high price. But it is not clear, what do the manufacturers mean when they call their parts “plasma”? Any spark plug is a plasma generator, because the spark discharge is pure cold plasma. Therefore, there is no point in overpaying if the candles have no other real distinguishing characteristics.
But they should also be treated with expertise. Manufacturers claim that plasma, as well as pre-chamber or plasma-porous spark plugs have a positive effect on the dynamics of the car. However, a number of experiments have shown that there is no difference between innovative and standard single-electrode spark plugs in this regard. Your car will drive with plasma spark plugs with the same dynamics, the same gasoline consumption and the same amount of harmful emissions as a standard spark plug.
A well-known proverb says: trust but verify. If you don’t want to check your own experience, then listen to the experts. And don’t assume that you’ve done something wrong if you use standard spark plugs and change them as needed.