7 best spark plugs

Candles from a world famous brand are almost a complete copy of the original - it is almost impossible to distinguish them without looking at the marking. Nickel plating of electrodes ensures Denso spark erosion resistance and high resource.To a certain extent, the culture of candle production can be assessed with the help of an elementary loupe: the side electrodes are stamped smoothly, soldered without the slightest bias. Due to this, Denso spark plugs are distinguished by stable spark formation, which guarantees smooth engine operation and regular fuel consumption.

The clearance of both side electrodes is set to the standard value for Renault - 1 mm.

A classic single-electrode spark plug from a well-known brand that is a part of the Federal Mogul concern. You should not expect outstanding results or a high resource from it - it will cope with the task of “moving away from maintenance to maintenance,” but no more.

In comparison with the leaders of the rating, Z193 candles have three obvious disadvantages:

• Potentially less resource due to single-electrode design.
• A smaller spark gap (0.9 mm) on the one hand will make it easier to start the engine with a battery that has run down (a smaller spark gap is easier to punch, if the voltage drops in the on-board network, even 0.1 mm becomes a sensitive difference), but on the other hand it will reduce the power of the spark. On gasoline of the best quality, this can lead to sporadic misfire in high load modes.
• The recessed central electrode impairs the ventilation of the spark gap, which also worsens the ignition conditions (these words should not be taken as an indicator of a noticeable drop in power - the real difference can be seen only on a dynamometer).

On the other hand, the low price and widespread prevalence have added to the overall rating score.

Two-electrode candle, which can be considered as an affordable alternative to standard candles. The central electrode of candles of this series is doped with yttrium, which should provide good resistance to spark erosion and, accordingly, a decent resource.

The quality of manufacture of spark plugs is not inferior to the leaders of the rating: the electrodes are soldered evenly, the markings on the metal skirt are packed evenly (the symbols packed with a skewed depth are one of the obvious signs of counterfeit). Only the gap between the electrodes causes displeasure - just like the majority of candles in the rating, it is slightly less than the recommended one.

In general, the Bosch candle is a direct analogue to the slightly cheaper Beru candle according to its performance. Taking into account that with the lottery quality of fuel (especially in the outback), the resource of a candle does not always limit only the technology of its manufacture, the large compared with the Z193 price outweighed the use of doped metal, and the rating of Bosch was lowered.

The candles produced by the Japanese company NGK, alas, have long been a symbol of poor quality - but the reason is not low production standards, but a huge amount of Chinese counterfeit, thrown into the market under this brand. Prior to the spread of large retail chains of auto parts, most auto shops, operating on the principle of “buy cheaper - sell more expensive”, flooded their counters with a frank “leftist”, which was easily distinguished by crookedly soldered electrodes and unevenly filled “Made in France” markings (which is characteristic, other countries on the NGK counterfeit spark plugs were rarely indicated).

Now, however, consider the original. This candle is similar in construction to the original one and in the same way has interelectrode gaps carried to the combustion chamber. However, a closer look reveals its shortcomings:

• Rough stamping of the side electrodes, especially noticeable from the ends, where a spark is formed - erosion will quickly destroy sharp protruding edges and the gap will change. Hence the instability of the spark, noticed in many multi-electrode NGK spark plugs, especially under high pressure - often the loss of power by the motor becomes quite noticeable.
• The spark gap itself is set to a size of 0.9 mm, which is slightly less than the "set".

If we take into account not the best workmanship and price, comparable to better candles, BKR6EK get the last place in the ranking.

One point is interesting - despite the maximum similarity of the BKR6EK in terms of the parameters to the original Renault candles, the NGK catalog indicates for the K7M motor only one-electrode applicability of the BKR6E. In principle, this option is more reasonable for financial reasons: these candles cost around 100 rubles with the same quality of manufacture.

NGK iridium plugs are noticeably superior in performance to their conventional design, but the parameters still do not coincide with the requirements of Renault: here the interelectrode gap is only 0.8 mm. It makes sense to install such candles on a new engine that does not have a perceptible oil consumption — in this case, the reduced clearance combined with the sparking stability provided by the central electrode with a diameter of less than a millimeter guarantee starting even on a well-discharged battery.

With careful selection of gas stations, iridium candles have a decent resource that can go up to 50,000 kilometers. People who often drive far in different directions, it is better to think about buying two sets of ordinary candles for the same money - to deactivate an expensive set of candles with random refueling is not the best option.