Continuing development


On the path of progress

You do not need to be a professional industry expert in order to understand quite obviously — in one moment all cars from the economy will not disappear anywhere. The process of transformation of the world park, leaching from it such cars and replacing their electric vehicles will certainly dragge on the years. Moreover, perhaps even for decades. So, the need for ignition candles will remain for quite a long time. And not just in candles, and the candles of high-tech, which meet the high requirements from the point of view of consumer properties, technical characteristics, etc.

All these requirements are formed by existing trends developing over the past few years.

In the applied sense, the necessary results are largely achieved at the expense of the so-called down-sizing — that is, reduce the size of the engines and their components: while maintaining the power parameters of the aggregates, and more often even when they are magnified, the volume of combustion chambers decrease. That is, with a unit of volume, more and more power is removed.

Maryan Smok, Bosch Product Specialist for Ignition Candles:

As a result, an inevitable rise in temperature in the combustion chamber, which is most directly reflected in the ignition candles, since the overheating for them is fraught, perhaps the most adverse effects. They are expressed in the occurrence of a vibil ignition capable of driving the engine. Therefore, for more hot engines, appropriate candles are needed, suitable for them in their temperature characteristics.

Andrei Rybkin, Technical Specialist, NGK Spark Plugs Eurasia:

It is also important to use, as Maryan Smok, directed by the side electrode indicates. Reliable ignition of the mixture in engines with direct injection of fuel is achieved due to the precision features of candles with a directed side electrode, the clearance of which is adjustable at the factory. Depending on the type of engine, the mounting angle of the electrodes and their position relative to the injector are determined.

Marian Smeck:

«Precious» candles

In turn, the constantly tightening environmental requirements for the cleaning of exhaust gases — lead to the fact that the engines must, firstly, to work correctly on the depleted fuel-air mixture, secondly, to ensure the most efficient combustion of the mixture so that the minimum number of unburned fuel fall into the release system Og.

In principle, it is precisely with this mainly the widespread spread of platinum and iridium candles with thin electrodes — a thin electrode allows the mixture to burn more efficiently — due to its best propagation along the combustion chamber.

That is, first of all, thin electrodes are used for this, and, accordingly, the use of new materials is already a consequence, because in a thin electrode less than metal. If a thin electrode is made from a nickel alloy, as in standard candles produced over the entire decades, then the resource of the spark plugs is very much reduced. By virtue of this, the electrodes have to perform from more wear-resistant materials, which, on the one hand, are less susceptible to electric square erosion when sparking so that the metal is less than destroyed. On the other hand, so that they can withstand high temperatures, which we have already spoken above.

Marian Smeck:

Alexey Strehchkov:

As you know, in parallel with platinum, iridium candles are actively used, and iridium in its technical parameters in this context is much better than platinum. Therefore, the choice between iridium candle and platinum is due to the classic compromise «price-characteristic».

Andrei Rybkin:

Of course,


That’s why

In general, the platinum group metals have a high melting point — up to two or more than a thousand degrees. In this regard, the electrodes less «burn out» and the candles can be used longer.

In addition to the quality characteristics of metals, the purity of the alloys used is also affected on operational performance. The absence of impurities is important. Therefore, the production culture is of great importance and also plays a big role in the work of the spark plug.

It is worth noting that the precious metals are contained in the attack on the electrodes, and not entirely in the candle case.

Marian Smeck:

«Eternal» candles?

Regularly on different channels are reported on the creation of the so-called «eternal» spark plugs that are once installed
In the car during its production and regularly function the entire service life of the vehicle. While «live» no one has seen such candles, but what our experts think about the very possibility of developing such candles.

Andrei Rybkin:



Alexey Strekhkov agrees with Andrey:

Marian Smun

Hauling — a terrible sin

As practice shows, in the general case, the main problem when installing spark plugs, there is still their hauling. Candles are very demanding to the effort used during installation — even not very significant exceeding it violates their work. Again, this is primarily due to the temperature regime — the metal of the case begins to stretch the housing and microstractions, a kind of microcamials between the ceramics of the insulator and the metal appears. Because of this, not the entire volume of heat that enters the insulator can dissipate into the case and further go into the head of the cylinder block, in the cooling channels. As a result, the candle begins to overheat. At the same time, even if it looks whole outside with a naked eye, but it was pulled during the installation, the negative consequences will not be revealed to express themselves.

Andrei Rybkin:

Alexey Strehchkov:


Marian Smun

Correct information about tightening moments can be easily found in the open access. It certainly is present in catalogs of conscientious manufacturers, on their sites, in reference book.

The force depends on several parameters — the diameter of the thread of the spark plug, its type and material of the sealing ring. There are candles without rings with a conical landing — they have a lot of effort.

Andrei Rybkin:


Some mechanics forget about special requirements in case of re-installing the spark plug after dismantling it for repair and diagnostic work. And they mean are pretty important.

First, in principle, re-installation is recommended no more than once. If this operation is carried out the third, fourth, etc., then the sealing ring can be deformed too much, and the candle will not be able to work as it should.

Secondly, when the candle is set again, the ring is already deformed by the primary installation, respectively, and the angle to which it must be wrapped will be less — 1/12 turnover (or 30 degrees). Roughly speaking — from the hand to spin and slightly at 30 degrees to tighten the key — this will already be enough. Otherwise, the candle will be pulled.

These requirements — efforts or angles of trust — differ from different manufacturers, because different materials are used, different alloys, different sealing rings profile, and so on. That is, you always need to look at what is written on a specific box of a specific candle installed.

And not remembering the memory, which effort was prescribed for a similar candle, for example, the same diameter, but another manufacturer.

General order

Experts should adhere to a certain order of action when replacing the ignition candles. At first, as Maryan Smuske recommends, an inspection of a motor compartment and a car engine is carried out for common faults. Further, the staff employee checks whether the ignition system is wiring, disconnects the connectors and estimates the state of the contacts and wires. The specialist then removes coarse contamination in the area of ​​placing candles and purifies with compressed air deposits and contamination in the knob of the candle. Only after that you can proceed directly to the dismantling of the candle itself and unscrew the old component. After removing the part, it should be examined for determining the signs of malfunctions in the engine.

Marian Smeck:

Andrei Rybkin:

— 90%


The main danger when installing candles is damage to the thread of the block head. In this case, the car owner threatens complex and expensive repairs.
And in modern engines with direct injection, this repair will often be impossible — you will have to buy a new head of the block!

When connecting high-voltage wires to the candles, they are sometimes confused by their order — it can damage the parts of the engine, burn the components and even lead to a fire! Due to the incident to the exhaust fuel to the exhaust system, the risk of failure of an expensive catalytic neutralizer appears.

Marian Smeck:

It is impossible to disagree with the expert. Replacing the ignition candles is really a very responsible operation, and only in the case when it is done correctly, the candle will last a period. But the wrong actions will lead to a rapid way out of order, even the most modern, high-tech spark plug.

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