Iridium Spark Plugs, Advantages and Disadvantages


With the onset of cold weather, motorists are faced with a problematic engine start every year. The problem is that in the cold the air is rarefied and in order to ignite the air-fuel mixture, a more powerful discharge from the candle is required.

In diesel engines, the problem is similar, but there ignition occurs due to the strong heating of the air in the cylinder from its compression. To solve this problem, engineers developed glow plugs.

Iridium Spark Plugs, Advantages and Disadvantages

What is the solution for gasoline internal combustion engines? It is quite clear that you need to do something with the standard candles. Over the course of more than a decade, the technology for creating SZ has developed, thanks to which various modifications have become available to drivers. Among them are iridium candles. Let's look at how they differ from the standard ones and how they work.


The principle of operation of iridium candles

Iridium spark plugs have the same design as the standard version (for more details on these elements, see in another article). The principle of operation is as follows.

A short electrical impulse is supplied through the high-voltage wires through the candlestick to the contact nut. A contact head is located inside the ceramic insulator. Through it, a high voltage current pulse enters the sealant connecting the contact head and the electrode. This is a positively charged current.

Iridium Spark Plugs, Advantages and Disadvantages

All spark plugs are fitted with a threaded skirt body. It firmly fixes the device in the spark plug well of the engine. In the lower part of the body there is a metal tendril - a side electrode. This element is bent towards the central electrode, but they do not connect. There is some distance between them.


A critical amount of current accumulates in the central part. Due to the fact that both electrodes are not isolated and have a high conductivity index, a spark arises between them. The strength of the discharge is affected by the resistance that both elements have - the less it is, the better the beam.

The larger the diameter of the central electrode, the smaller the plasma core will be. For this reason, not pure metal is used, but iridium, more precisely, its alloy. The material has a high electrical conductivity and is not so strongly susceptible to the absorption of thermal energy released during the formation of an electric discharge beam.

Iridium Spark Plugs, Advantages and Disadvantages

The electric spark is not scattered over the entire surface of the central electrode; therefore, such a plug provides the combustion chamber with a "fat" discharge. This, in turn, improves ignition of the cold mixture of air and gasoline (or gas, which has a temperature of about -40 Celsius in the cylinder).

Iridium Candle Maintenance Process

The spark plug with an iridium core does not require any special maintenance. In most engines, these modifications run over 160 kilometers. For the stable operation of the internal combustion engine, manufacturers recommend changing the candles not when they fail, but periodically - in many cases a little more often than after 000 thousand.

Iridium Spark Plugs, Advantages and Disadvantages

Although carbon deposits do not form so much on iridium models, due to the poor quality of gasoline and frequent cold engine starts, this plaque still appears. For these reasons, it is recommended that you refuel your vehicle at proven gas stations and minimize short-distance travel.

Benefits of iridium candles

The advantages that this type of elements of the ignition system have include the following factors:

  • The engine becomes more efficient. This indicator is provided due to the rather small contact surface on the electrodes. The process of starting the power unit becomes faster due to a concentrated electric beam, for the formation of which less voltage is used;
  • Stabilization of work at idle. When the temperature of the air entering the motor is negative, a better spark is needed. Since the iridium plug requires less voltage and creates a better spark, even an unheated motor will be more stable at low speeds;
  • In some units, the use of this type of plug has led to a reduction in gas mileage of up to about 7 percent. Thanks to a better ignition of the BTC, it burns more efficiently and less harmful gases enter the exhaust system;
  • Car ignition requires routine maintenance. In the case of using the discussed candles, maintenance is carried out after a longer period. Depending on the engine model, the work of the candles is possible in the range between 120 and 160 thousand kilometers;
  • The properties of iridium give the electrode a great resistance to melting, which allows the spark plug to withstand high temperatures in a boosted engine;
  • Less susceptible to corrosion;
  • A guarantee of a stable spark under any operating conditions of the motor.

Are there any disadvantages to this type of spark plug?

Iridium Spark Plugs, Advantages and Disadvantages

Naturally, SZ with an iridium electrode also have a disadvantage. To be more precise, there are several of them:

  • Are expensive. Although there is a "double-edged sword". On the one hand, they are decent, but on the other, they have an increased resource. During the operation of one set, the driver will have time to replace several budget analogues;
  • Many older car owners have had bitter experience with these SZs. However, the problem is no longer in these consumables, but in the fact that they are mainly created for modern power units. A motor with a volume of up to 2,5 liters will not feel the difference from installing a non-standard SZ.

As you can see, the installation of such elements will be noticeable on more efficient motors. They are, for example, used in racing vehicles: for rallies, drifting or other types of competition.

If the car is old with a small-displacement internal combustion engine, then there will be more than enough standard candles. The main thing is to change them in time so that the ignition coil does not overload due to the formation of carbon deposits (when to do this, it is told here).

Differences between iridium spark plugs and standard spark plugs

Iridium Spark Plugs, Advantages and Disadvantages

Here is a small comparison table between iridium and classic SZ:

Candle type:ProsCons
StandardLow cost Can be used on any gasoline unit; Not very demanding on the quality of fuelA small resource due to the quality of the electrode material; Cold start of the motor is not always stable due to the large scattering of the beam; The carbon deposits accumulate faster (its amount also depends on how the ignition system is configured); For effective ignition of the mixture, high voltage is required
Doped with iridiumSignificantly increased working life; More assembled and powerful beam due to the design features of the part; Improves the stability of the motor; In some cases, there is an increase in the performance of the unit due to better combustion of the VTS; Sometimes it leads to an increase in the efficiency of the motorHigh price; Whimsical to the quality of gasoline; When installed on a small-displacement unit, improvements in its operation are not observed; Due to the fact that the consumable changes less often, more foreign particles (carbon deposits) can accumulate in the engine

Iridium spark plugs cost

As we have already found out, in comparison with classical candles, the iridium analogue sometimes costs three times more. However, if we compare them with the platinum counterpart, then they occupy the niche of goods in the middle price segment.

Iridium Spark Plugs, Advantages and Disadvantages

This price range is no longer related to the quality and efficiency of the product, but rather to its popularity. Interest in iridium candles is fueled by the reviews of professional racers, who often feel the difference from the use of these consumables.

As we are accustomed to, the price is generated not by quality, but by demand. As soon as people switch to cheaper meat, the expensive one immediately drops in price, and the process reverses with the budget option.

Although iridium is a very rare metal (compared to gold or platinum), among auto parts, candles with electrodes alloyed with this metal are more common. But their price is due precisely to the popularity of the product, because a meager amount of this material is used for the production of a part. In addition to soldering on the end of the electrodes, this is mainly a conventional spark plug.

Here's a short video on the biggest cons of iridium consumables:

Iridium candles or not?


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