Service life of iridium spark plugs

When it comes time to change the candles in the car, the driver gets a difficult choice: you can get a cheap set of copper or buy something more expensive, but safer. Now iridium spark plugs have made a worthy competition to platinum candles, which every year become more and more popular in the production of auto parts. In general, iridium was recently used to produce machine-made candles. Only in 1994, the company NGK first demonstrated iridium candles.

Then it became a real breakthrough. Innovation quickly came into use. Of the merits, it was noted that iridium is excellent for use in a vehicle, since it has a very high melting point and high resistance to corrosion. Soon, NGK created and launched the thinnest electrode wire, for the tip of which the iridium electrode material was used.

Iridium spark plugs

Iridium spark plugs

If we talk about the company DENSO, their iridium spark plugs are made specifically for modern-generation gasoline engines. The company appeared later in 1996 in Japan, but despite this, its products are also common. The DENSO candle consists of a central electrode, which is made of a nickel-chromium alloy with a copper core, which gives a high thermal stability and an extended working range.


  • 1 What is iridium and its history
  • 2 Cost of iridium candles
  • 3 The main characteristics of iridium candles
  • 4 Pros and cons of iridium spark plugs
  • 5 Service and replacement of candles

What is iridium and its history

Currently, many motorists prefer it iridium sets of candles. It is connected with: with a long service life of products, the highest quality and great resource, which increases the power of the vehicle. Their only drawback is the high price, which not everyone can afford. The high cost is due to the fact that iridium is a rather rare and solid metallic formation.

It is believed that the material appeared many years ago on our planet due to meteoric rains. In addition to the above properties, there is another merit that makes it indispensable in the automotive industry - this high melting point (2500 ° С). However, as it turned out, in its pure form, the material does not have all the above properties. Since it is in itself more fragile and has less electrical conductivity. Therefore, they began to use it only at the end of the 20th century and then in the composition of various alloys, which just supplemented the missing properties.


Replacement candles

Cost of iridium candles

In the modern world, it is the cost of a particular part that is an important factor for making a purchase decision. Despite its considerable cost, iridium spark plugs are still cheaper than platinum ones. This is explained by the fact that this metal is not in great demand in the market. Because for the production of candles it takes a little. Thus, the alloy tip consists of half and rhodium.

About 20% of all mined iridium goes exactly to the spark plugs for vehicles. In the case of platinum, this figure is much lower, since most of this metal goes to jewelry and catalytic converters. In addition, for candles, very little iridium is used: only for the production of tips and grounding electrodes. Nevertheless, because of its rarity, the cost of sets of iridium candles is still quite high. The price of one candle can be equal from 600 to 800 rublesand if we consider a kit, from 2500 to 2800 rubleswhile a set of simple costs within three hundred rubles.

See also: How to remove the battery from the car

The main characteristics of iridium candles

  1. The secret of modern iridium candles is that the electrodes are connected by laser welding. Due to the good conductivity of the material, it allows you to create very fine tips of a very small size, which is very advantageous compared to using copper and platinum. In addition, it does not affect the service life of iridium spark plugs.

    Срок службы иридиевых свечей зажигания

    Set of iridium candles

  2. The small diameter of these candles creates a more concentrated electric charge, which, in turn, allows you to create a small voltage for the transition of the spark gap. Thanks to this, the car will run more smoothly, accelerate faster, and the combustion will improve during any type of driving. Iridium allows the electrodes to always be at an equal distance and keep the spark.
  3. The number of side electrodes. The standard option is one central and side electrode. There were models consisting of two, three, four electrodes. Novelty - no side electrodes.
  4. In addition, iridium has the highest strength and the ability to stably maintain a spark. Iridium in all situations will retain all the virtues. Its density is 22, 65 g / cc. cm. Because of this, the material exceeds osmium by gravity. The hardness of the element is 6.5 on the Mohs scale, whether this means that the material is not subject to wear.
  5. Due to the high melting point of iridium alloy, it is suitable for use in most high-tech engines characterized by high operating efficiency. The temperature of the working candles in all modes of operation of the motor should be within about 500-900 degrees Celsius.
  6. Trivalent nickel coating perfectly protects parts from corrosion. For a spark to occur, much less voltage is required, since the entire potential difference is concentrated in the tiny tip of the spark plug. In addition, iridium allows you to improve the acceleration of the car and improve fuel efficiency.

    How many iridium spark plugs go

    Iridium candles DENSO

Pros and cons of iridium spark plugs

Of course, when choosing parts for a vehicle, an important factor is the price. However, in this case it should not be decisive. When using inexpensive spark plugs, it is likely that you will soon have to change them or even repair the engine. Therefore, it is better to learn the main advantages and disadvantages, as well as reviews of car owners, to make an informed decision.


  • they possess high work efficiency in comparison with the others. Thanks to the construction of a thin wire with a diameter of only 0.4 mm, manufacturers were able to minimize the contact area between the core of the flame and the electrode. In addition, iridium itself creates a more powerful spark with less voltage, which significantly improves the quality of the launch;
  • this metal provides reliable ignition of candles even at idle, so you will no longer have such problems as when using alternatives from copper or other material. Iridium candles can not only ensure the stability of the power unit, but also to ensure high efficiency of fuel combustion and a greater number of revolutions;
  • their use ensures that the power unit of your vehicle can work 7–8% more efficiently;
  • allows you to save on fuel and also reduce its toxicity. And this is not an assumption, but a fact, confirmed by experience and research;
  • thanks to them, you will forget about the problems with the engine factory in bad and frosty weather. This becomes possible due to their high work efficiency;

    Iridium spark plugs

    NGK spark plugs

  • reduce acceleration time, increase the rated power of the motor. Candles of this type are massively used in racing cars that require a high engine speed of up to 20 thousand rpm;
  • increase the life of the car. If you are wondering how much iridium spark plugs go, the manufacturers will calmly answer you: 150-160 thousand kilometers. And although in fact this indicator is slightly lower (100-120 thousand kilometers), it largely depends on how well your engine works and how much quality fuel you use. No matter how, their lifespan is several times longer than that of ordinary candles.


  • One of the significant drawbacks that can stop many motorists from buying iridium candles, is their rather high price. However, according to the manufacturers and those who have already used them, it fully justifies itself. Very soon you will start to notice the positive dynamics of your vehicle;
  • It is also worth considering that these parts are focused on use in high-tech and powerful engines. If you have a standard car, they may not meet your expectations.


    History of iridium candles

Service and replacement of candles

Although manufacturers of iridium spark plugs for cars claim that they need to be replaced. every 150-160 thousand kilometers, experts recommend doing it a little more often. This is due to the fact that the frequency and efficiency of their work are strongly influenced by the frequency of the engine plant and the quality of its work, the quality of the fuel, the level of environmental pollution, etc. necessary specialized equipment.

The meaning of buying iridium kits is only from owners of expensive cars with mileage, crossing over 5 thousand km per year.

When you pick up a replacement for worn parts, you need to pay attention to the thread diameter, length and pitch, but the configuration of the wires may be different from what was in the source. You should also pay attention to the heat of the number, if it is chosen incorrectly, then there will be a deposit of carbon on the candle, or the detonation of the engine cylinders. Nagar on the candles occurs when energy leaks to the body, while the power between the side and central electrode weakens. Therefore, before buying, you need to rely only on the recommendations of the manufacturer of your vehicle.