Spark plug markings

Spark plug markings of domestic and foreign manufacturers informs the car owner about the size of the thread, the length of the threaded part, its glow number, the presence or absence of a resistor and the material from which the core is made. Sometimes the designation of spark plugs characterizes other information, for example, information about the manufacturer or the place (factory / country) of the manufacturer. And in order to correctly select a candle for the internal combustion engine of your car, you need to know how to decipher all the letters and numbers on it, because different companies have different markings.

Despite the fact that the numbers and letters on spark plugs from different brands will be denoted differently in marking, most of them are interchangeable. At the end of the material there will be a table with relevant information. But first, let's look at how the marking of spark plugs of the most popular manufacturers is deciphered.

Spark plug marking for RF

All spark plugs manufactured by factories in the Russian Federation fully comply with the international standard ISO MS 1919, and therefore are fully interchangeable with imported ones. However, the marking itself is adopted uniform throughout the country and is spelled out in the regulatory document - OST 37.003.081-98. In accordance with the specified document, each candle (and / or its packaging) contains encrypted information consisting of nine characters. However, in some cases there may be fewer of them, up to three for cheap candles that have a set of basic functions.

In general terms, the designation of a candle according to the Russian standard will look schematically as follows: size and thread pitch / shape of the supporting surface (saddle) / key size for installation / glow number / length of the threaded part of the body / presence of insulator protrusion / presence of a resistor / material of the central electrode / information about the modification. See below for details on each item listed.

1. Body thread, in millimeters. The letter A means a thread of size M14 × 1,25, the letter M - thread M18 × 1,5.
2. Thread form (support surface). If the letter K is in the designation, then the thread is conical, the absence of this letter will indicate that it is flat. Currently, regulations require the production of candles with flat threads only.
3. Key size (hexagon), mm. The letter U is 16 millimeters, and the M is 19 millimeters. If the second character is absent at all, then this means that you need to use a 20,8 mm hexagon for work. Please note that candles with a threaded part of the body equal to 9,5 mm are produced with a M14 × 1,25 thread for a 19 mm hexagon. And candles with a body length of 12,7 mm are also threaded M14 × 1,25, but for a hexagon 16 or 20,8 mm.
4. Heat number of spark plug. In the specified standard, the following options are possible - 8, 11, 14, 17, 20, 23, 26. The lower the corresponding value, the hotter the candle. Conversely, the higher it is, the colder it is. In addition to the glow number in the marking, cold and hot candles differ in the shape and area of ​​​​the central electrode insulator.
5. Body thread length. The letter D means that the corresponding value is 19 mm. If there is no symbol in this place, then the length will be 9,5 or 12,7 mm, this can be found from the information about the size of the hexagon for attaching the candle.
6. Presence of the thermal cone of the insulator. The letter B means that it is. If this letter does not exist, the protrusion is missing. Such a performance is necessary to accelerate the heating of the candle after starting the internal combustion engine.
7. The presence of a built-in resistor. The letter P in the designation of Russian standard spark plugs is put if there is an anti-interference resistor. In the absence of such a resistor, there is no letter either. The resistor is needed to reduce radio interference.
8. Center electrode material. The letter M means that the electrode is made of copper with a heat-resistant shell. If this letter is absent, then the electrode is made of a special heat-resistant nickel alloy.
9. Sequence number of development. It can have values ​​from 1 to 10. Two options are possible here. The first is encrypted information about the size of the thermal gap in a particular candle. The second option - this is how the manufacturer records encrypted information about design features, which, however, do not play a role in the applicability of the candle. Sometimes this means the degree of modification of the candle pattern.

Marking spark plugs NGK

Like other spark plug manufacturers, NGK labels its spark plugs with a set of letters and numbers. However, a feature of NGK spark plug markings is the fact that the company uses two standards. One uses seven parameters, and the other uses six. Let's start the description from the first.

In general, the symbols will report the following information: thread diameter / design features / presence of a resistor / glow number / thread length / candle design / electrode gap size.

Dimensions thread and hexagon diameters

The corresponding sizes are encrypted as one of nine letter designations. further they are given in the form: candle thread diameter / hexagon size. So:

• A - 18 mm / 25,4 mm;
• B - 14 mm / 20,8 mm;
• C - 10 mm / 16,0 mm;
• D - 12 mm / 18,0 mm;
• E - 8 mm / 13,0 mm;
• AB — 18 mm / 20,8 mm;
• BC - 14 mm / 16,0 mm;
• BK - 14 mm / 16,0 mm;
• DC - 12mm / 16,0mm.

Design features of the spark plug

There are three types of letters here:

• P - the candle has a protruding insulator;
• M - the candle has a compact size (the thread length is 9,5 mm);
• U - candles with this designation have either a surface discharge or an additional spark gap.

The presence of a resistor

Three design options are possible:

• this field is empty - there is no resistor from radio interference;
• R - the resistor is located in the design of the candle;
• Z - an inductive resistor is used instead of the usual one.

Heat number

The value of the glow number is determined by NGK as integers from 2 to 10. At the same time, candles marked with the number 2 are the hottest candles (they give off heat poorly, have hot electrodes). Conversely, the number 10 is a sign of cold candles (they give off heat well, their electrodes and insulators heat up less).

Thread length

The following letter designations are used to designate the thread length on a spark plug:

• E - 19 mm;
• EH - total thread length - 19 mm, and partially cut thread - 12,7 mm;
• H — 12,7 mm;
• L - 11,2 mm;
• F - the letter means a conical tight fit (private options: AF - 10,9 mm; BF - 11,2 mm; B-EF - 17,5 mm; BM-F - 7,8 mm);
• the field is empty, or the designations BM, BPM, CM are a compact candle with a thread length of 9,5 mm.

Design features of NGK spark plugs

This parameter contains many different design features of both the candle itself and its electrodes.

• B - in the design of the candle there is a fixed contact nut;
• CM, CS - the side electrode is made inclined, the candle has a compact type (the length of the insulator is 18,5 mm);
• G - racing spark plug;
• GV - spark plug for sports cars (the central electrode is of a special V-shaped type and is made of an alloy of gold and palladium);
• I, IX - the electrode is made of iridium;
• J - firstly, there are two side electrodes, and secondly, they have a special shape - elongated and inclined;
• K - there are two side electrodes in the standard version;
• L - the symbol reports the intermediate glow number of the candle;
• LM - compact type of candle, the length of its insulator is 14,5 mm (used in ICE lawn mowers and similar equipment);
• N - there is a special side electrode;
• P - the central electrode is made of platinum;
• Q - the candle has four side electrodes;
• S - standard type of candle, size of the central electrode - 2,5 mm;
• T - the candle has three side electrodes;
• U - candle with a semi-surface discharge;
• VX - platinum spark plug;
• Y - the central electrode has a V-shaped notch;
• Z - a special design of the candle, the size of the central electrode is 2,9 mm.

Interelectrode gap and features

The value of the interelectrode gap is indicated by numbers, and the features by letters. If there is no number, then the gap is standard for a passenger car - about 0,8 ... 0,9 mm. Otherwise it is:

• 8 - 0,8 mm;
• 9 - 0,9 mm
• 10 - 1,0 mm
• 11 - 1,1 mm
• 13 - 1,3 mm
• 14 - 1,4 mm
• 15 - 1,5 mm.

Sometimes the following additional designations are found:

• S - the symbol means that there is a special sealing ring in the candle;
• E - the candle has a special resistance.

further information is provided on the standard for marking ngk spark plugs by designation with six-row characters in the marking. In general terms, it looks like this: type of candle / information about the diameter and length of the thread, type of seal, key size / presence of a resistor / glow rating / design features / gap size and features of the electrodes.

spark plug type

There are five typical letter designations and one additional, which will be discussed below. So:

• D - the candle has a particularly thin central electrode, positioned by the manufacturer as a product with increased ignition reliability;
• I - designation of an iridium candle;
• P - this letter denotes a platinum candle;
• S - the candle has a square platinum insert, the purpose of which is to provide increased ignition reliability;
• Z - the candle has a protruding spark gap.

An additional letter designation, which can sometimes be found in a marking combination, is the letter L. Such candles have an elongated threaded part. For example, the designation of a candle FR5AP-11 gives the car owner information that its thread length is 19 millimeters, and for LFR5AP-11 it is already 26,5 millimeters. so, the letter L, although it does not refer to the type of candle, but has priority.

Information about diameter, thread length, seal type, hex size

there are as many as 15 different letter designations. the following information is given in the form: thread diameter [mm] / thread length [mm] / type of seal / hexagon size for installation [mm].

• KA - 12 mm / 19,0 mm / flat / 14,0 mm;
• KB - 12mm, 19,0mm flat / 14,0 type Bi-Hex bits;
• MA - 10 mm, 19,0 mm, flat / 14,0 mm;
• NA - 12 mm, 17,5 mm, tapered / 14,0 mm;
• F - 14 mm, 19,0 mm, flat / 16,0 mm;
• G - 14 mm, 19,0 mm, flat / 20,8 mm;
• J - 12 mm, 19,0 mm, flat / 18,0 mm;
• K - 12 mm, 19,0 mm, flat / 16,0 mm;
• L - 10 mm, 12,7 mm, flat / 16,0 mm;
• M - 10 mm, 19,0 mm, flat / 16,0 mm;
• T - 14 mm, 17,5 mm, tapered / 16,0 mm;
• U - 14 mm, 11,2 mm, tapered / 16,0 mm;
• W - 18 mm, 10,9 mm, tapered / 20,8 mm;
• X - 14mm, 9,5mm flat / 20,8mm;
• Y - 14 mm, 11,2 mm, tapered / 16,0 mm.

The presence of a resistor

If the letter R is in the third place in the marking, then this means that there is a resistor in the candle to suppress radio interference. If there is no specified letter, then there is no resistor either.

Heat number

Here the description of the glow number completely coincides with the first standard. Number 2 - hot candles, number 10 - cold candles. and intermediate values.

Information about design features

Information is presented in the form of the following letter designations:

• A, B, C - designation of design features that are not important for an ordinary motorist and do not affect performance;
• I - central electrode iridium;
• P - central electrode platinum;
• Z is a special design of the electrode, namely, its size is 2,9 millimeters.

Interelectrode gap and features of electrodes

The interelectrode gap is indicated by eight numerical designations:

• empty - standard clearance (for a passenger car, it is usually in the range of 0,8 ... 0,9 mm);
• 7 - 0,7 mm;
• 9 - 0,9 mm;
• 10 - 1,0 mm;
• 11 - 1,1 mm;
• 13 - 1,3 mm;
• 14 - 1,4 mm;
• 15 - 1,5 mm.

the following literal encrypted information can also be given here:

• A - electrode design without sealing ring;
• D - special coating of the metal body of the candle;
• E - special resistance of the candle;
• G - side electrode with a copper core;
• H - special candle thread;
• J - the candle has two side electrodes;
• K - there is a side electrode protected from vibration;
• N - a special side electrode on the candle;
• Q - candle design with four side electrodes;
• S - there is a special sealing ring;
• T - the candle has three side electrodes.

Marking of Denso spark plugs

Denso spark plugs are among the best and most popular on the market. That is why they are included in the rating of the best candles. the following is information about the basic points in the marking of Denso candles. The marking consists of six alphabetic and numeric characters, each of which carries certain information. The decryption is described in order from left to right.

In general terms, it looks like this: material of the central electrode / diameter and length of the thread, key size / glow number / presence of a resistor / type and features of the candle / spark gap.

Material for the manufacture of the central electrode

The information has an alphabetic type. namely:

• F - the central electrode is made of iridium;
• P is the platinum coating of the central electrode;
• I - iridium electrode with a diameter of 0,4 mm with improved characteristics;
• V - iridium electrode with a diameter of 0,4 mm with a platinum overlay;
• VF - iridium electrode with a diameter of 0,4 with a platinum needle also on the side electrode.

Diameter, thread length and hex size

followed by letter information indicating both the thread diameter / thread length / hexagon size, in millimeters. There may be the following options:

• CH - M12 / 26,5 mm / 14,0;
• K — M14 / 19,0 / 16,0;
• KA - M14 / 19,0 / 16,0 (screened candle, has new triple electrodes);
• KB - M14 / 19,0 / 16,0 (there are triple electrodes);
• KBH - M14 / 26,5 / 16,0 (there are new triple electrodes);
• KD - M14 / 19,0 / 16,0 (shielded candle);
• KH — М14 / 26,5 / 16,0;
• NH - M10 / 19,0 / 16,0 (half-length thread on the candle);
• T - M14 / 17,5 / 16,0 (conical socket);
• TF - M14 / 11,2 / 16,0 (conical socket);
• TL - M14 / 25,0 / 16,0 (conical socket);
• TV - M14 / 25,0 / 16,0 (conical socket);
• Q — M14 / 19,0 / 16,0;
• U — M10 / 19,0 / 16,0;
• UF — М10 / 12,7 / 16,0;
• UH - M10 / 19,0 / 16,0 (thread for half the length of the candle);
• W - М14 / 19,0 / 20,6;
• WF — М14 / 12,7 / 20,6;
• WM - M14 / 19,0 / 20,6 (there is a compact insulator);
• X — M12 / 19,0 / 16,0;
• XEN - M12 / 26,5 / 14,0 (screen with a diameter of 2,0 mm);
• XG - M12 / 19,0 / 18,0 (screen with a diameter of 3,0 mm);
• COINS — М12 / 19,0 / 16,0;
• XUH — М12 / 26,5 / 16,0;
• Y - M8 / 19,0 / 13,0 (half-length thread).

Heat number

This indicator at Denso is presented in digital form. It can be: 16, 20, 22, 24, 27, 29, 31, 32, 34, 35. Accordingly, the lower the number, the hotter the candles. Conversely, the higher the number, the colder the candles.

It is also worth noting here that sometimes the letter P is placed after the glow number in the designation. This means that not only the central electrode, but also the ground electrode is covered with platinum.

The presence of a resistor

If the letter R has a row indication of symbols, it means that the resistor is provided for by the design of the candle. If there is no specified letter, the resistor is not provided. However, according to statistics, resistors are installed on most Denso spark plugs.

Type of candle and its features

also often (but not always) additional information about its type is indicated in the marking. So, it could be:

• A - inclined electrode, without U-shaped groove, the shape is not cone-shaped;
• B - an insulator protruding to a distance equal to 15 mm;
• C - a candle without a U-shaped notch;
• D - a candle without a U-shaped notch, while the electrode is made of inconel (a special heat-resistant alloy);
• E - screen with a diameter of 2 mm;
• ES - the candle has a stainless steel gasket;
• F - special technical characteristic;
• G - stainless steel gasket;
• I - the electrodes protrude by 4 mm, and the insulator - by 1,5 mm;
• J - electrodes protrude by 5 mm;
• K - the electrodes protrude 4 mm, and the insulator protrudes 2,5 mm;
• L - electrodes protrude by 5 mm;
• T - the candle is designed for use in gas combustion engines (with HBO);
• Y - electrode gap is 0,8 mm;
• Z is a conical shape.

Spark gap size

Denoted by numbers. namely:

• if there are no numbers, then the gap is standard for a car;
• 7 - 0,7 mm;
• 8 - 0,8 mm;
• 9 - 0,9 mm;
• 10 - 1,0 mm;
• 11 - 1,1 mm;
• 13 - 1,3 mm;
• 14 - 1,4 mm;
• 15 - 1,5 mm.

Bosch spark plug marking

The Bosch company produces a huge variety of spark plugs, and therefore their marking is complex. However, in most cases, there are candles on sale, the marking of which consists of eight characters (as usual, there are less, namely seven for single-electrode candles).

Schematically, the marking looks like this: the shape of the support (saddle), diameter, thread pitch / modification and properties of the plug / glow number / thread length and the presence of electrode protrusion / number of grounding electrodes / material of the central electrode / features of the plug and electrodes.

Bearing surface shape and thread size

There are five lettering options:

• D - candles with a thread of size M18 × 1,5 and with a conical thread are indicated. For them, 21 mm hexagons are used.
• F - thread size M14 × 1,5. Has a flat sealing seat (standard).
• H - thread with size M14 × 1,25. Conical seal.
• M - the candle has a M18 × 1,5 thread with a flat seal seat.
• W - thread size M14 × 1,25. The sealing seat is flat. It is one of the most common types.

Modification and additional properties

It has five letter designations, among which:

• L - this letter means that the candle has a semi-surface spark gap;
• M - candles with this designation are designed for use in sports (racing) cars, have enhanced performance, but are expensive;
• Q - candles at the start of the internal combustion engine quickly gain operating temperature;
• R - in the design of the candle there is a resistor to suppress radio interference;
• S - candles marked with this letter are intended for use in low-power internal combustion engines (information on this must be specified in the vehicle documentation and other characteristics of the candle).

Heat number

Bosch produces candles with 16 different glow numbers - 13, 12,11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 09, 08, 07, 06. The number 13 corresponds to the "hottest" candle. And accordingly, their warmth is waning, and the number 06 corresponds to the “coldest” candle.

Thread length / presence of electrode protrusion

There are six options in this category:

• A - the thread length of such Bosch spark plugs is 12,7 mm, and the spark position is normal (there is no electrode protrusion);
• B - will show that the thread length is the same 12,7 millimeters, however, the position of the spark is advanced (there is an electrode protrusion);
• C - the thread length of such candles is 19 mm, the spark position is normal;
• D - thread length is also 19 mm, but with the spark extended;
• DT - similar to the previous one, the thread length is 19 mm with the spark extended, but the difference is the presence of three mass electrodes (the more mass electrodes, the longer the spark plug life);
• L - at the candle, the thread length is 19 mm, and the spark position is far advanced.

Number of mass electrodes

This designation is only available if the number of electrodes is from two to four. If the candle is an ordinary single-electrode, then there will be no designation.

• without designations - one electrode;
• D - two negative electrodes;
• T - three electrodes;
• Q - four electrodes.

Material of the middle (central) electrode

There are five lettering options, including:

• C - the electrode is made of copper (heat-resistant nickel alloy can be coated with copper);
• E - nickel-yttrium alloy;
• S - silver;
• P - platinum (sometimes the designation PP is found, which means that a layer of platinum is deposited on the nickel-yttrium material of the electrode to increase its durability);
• I - platinum-iridium.

Features of the candle and electrodes

Information is encoded digitally:

• 0 — the candle has a deviation from the main type;
• 1 — the side electrode is made of nickel;
• 2 - the side electrode is bimetallic;
• 4 - the candle has an elongated thermal cone;
• 9 - the candle has a special design.

Brisk spark plug markings

Candles from the Brisk company are very popular with motorists due to their good price-quality ratio. Let us dwell in more detail on the features of decoding the marking of Brisk spark plugs. For designation, there are eight numeric and alphabetic characters in the row.

They are arranged from left to right in the following sequence: body size / plug shape / type of high voltage connection / presence of a resistor / glow rating / design features of the arrester / material of the main electrode / gap between the electrodes.

Candle body dimensions

Deciphered in one or two letters. further values ​​are given in the form: thread diameter / thread pitch / thread length / nut (hex) diameter / type of seal (seat).

• A - M10 / 1,0 / 19 / 16 / flat;
• B - M12 / 1,25 / 19 / 16 / flat;
• BB - M12 / 1,25 / 19 / 18 / flat;
• C - M10 / 1,0 / 26,5 / 14,0 / flat;
• D - M14 / 1,25 / 19 / 16 / flat;
• E - M14 / 1,25 / 26,5 / 16 / flat;
• F - M18 / 1,50 / 11,2 / 21,0 / cone;
• G — M14 / 1,25 / 17,5 / 16 / conical;
• H — M14 / 1,25 / 11,2 / 16 / conical;
• J - M14 / 1,25 / 9,5 / 21 / flat;
• K - M14 / 1,25 / 9,5 / 21 / flat;
• L - M14 / 1,25 / 19 / 21 / flat;
• M - M12 / 1,25 / 26,5 / 14 / flat;
• N - M14 / 1,25 / 12,7 / 21 / flat;
• NA - M10 / 1,00 / 12,7 / 16,0 / flat;
• P - M14 / 1,25 / 9 / 19 / flat;
• Q - M12 / 1,25 / 26,5 / 16 / flat;
• R — M14 / 1,25 / 25 / 16 / conical;
• S - M10 / 1,00 / 9,5 / 16 / flat;
• T - M10 / 1,00 / 12,7 / 16 / flat;
• U — M14 / 1,25 / 16,0 / 16 / conical;
• 3V — M16 / 1,50 / 14,2 / 14,2 / conical;
• X - M12 / 1,25 / 14,0 / 14 / cone.

Form of issue

There are three lettering options:

• the field is empty (absent) — the standard form of issue;
• O - elongated shape;
• P - thread from the middle of the body.

High voltage connection

There are two options:

• the field is empty — the connection is standard, made according to ISO 28741;
• E - special connection, made according to the standard for the VW Group.

The presence of a resistor

This information is encrypted in the following form:

• the field is empty - the design does not provide for a resistor from radio interference;
• R - the resistor is in the candle;
• X - in addition to the resistor, there is also additional protection against burnout of the electrodes on the candle.

Heat number

On Brisk candles, it can be as follows: 19, 18, 17, 16, 15, 14, 12, 11, 10, 09, 08. The number 19 corresponds to the hottest spark plugs. Accordingly, the number 08 corresponds to the coldest.

Arrester design

The information is encrypted in literal form as follows:

• empty field - not removed insulator;
• Y - remote insulator;
• L - specially made insulator;
• B - thickened tip of the insulator;
• D - there are two side electrodes;
• T - there are three side electrodes;
• Q - four side electrodes;
• F - five side electrodes;
• S - six side electrodes;
• G - one continuous side electrode around the perimeter;
• X - there is one auxiliary electrode at the tip of the insulator;
• Z - there are two auxiliary electrodes on the insulator and one solid around the perimeter;
• M is a special version of the arrester.

Center electrode material

There can be six lettering options. namely:

• the field is empty — the central electrode is made of nickel (standard);
• C - the core of the electrode is made of copper;
• E - the core is also made of copper, but it is alloyed with yttrium, the side electrode is similar;
• S - silver core;
• P - platinum core;
• IR - on the central electrode, the contact is made of iridium.

Interelectrode distance

The designation can be both in numbers and in alphabetical form:

• empty field - a standard gap of about 0,4 ... 0,8 mm;
• 1 - 1,0 ... 1,1 mm;
• 3 - 1,3 mm;
• 5 - 1,5 mm;
• T - special spark plug design;
• 6 - 0,6 mm;
• 8 - 0,8 mm;
• 9 - 0,9 mm.

Champion Spark Plug Marking

Spark plugs "Champion" have a type marking consisting of five characters. The designation in this case is not entirely obvious to an ordinary person, therefore, when selecting, it is necessary to be guided by the reference information below. Characters are listed traditionally, from left to right.

In general terms, they are presented as follows: candle features / dimensions of the diameter and length of the thread / glow number / design features of the electrodes / gap between the electrodes.

Candle Features

Character options number one:

• B - candle has a conical seat;
• E - shielded candle with a size of 5/8 inch by 24;
• O - the design of the candle provides for the use of a wire resistor;
• Q - there is an inductive suppressor of radio interference;
• R - there is a conventional radio interference suppression resistor in the candle;
• U - the candle has an auxiliary spark gap;
• X - there is a resistor in the candle;
• C - the candle belongs to the so-called "bows" type;
• D - candle with a conical seat and "bow" type;
• T is a special "bantam" type (that is, a special compact type).

Thread size

The diameter and length of the thread on the candles "Champion" is encrypted in alphabetic characters, and at the same time it is divided into candles with a flat and conical seat. For convenience, this information is summarized in a table.

Index	Thread diameter, mm	Thread length, mm
flat seat
A	12	19
C	14	19,0
D	18	12,7
G	10	19,0
H	14	11,1
J	14	9,5
K	18	11,1
L	14	12,7
N	14	19,0
P	14	12,5
R	12	19,0
Y	10	6,3 ... 7,9
Z	10	12,5
Conical seat
F	18	11,7
S, aka BN	14	18,0
V, aka BL	14	11,7

Heat number

Under the Champion trademark, spark plugs are produced for a wide variety of vehicles. However, widely used plugs have a glow number ranging from 1 to 25. One is the coldest plug, and accordingly, 25 is the hottest plug. For racing cars, candles are produced with a glow number in the range from 51 to 75. The gradation of cold and hot is the same for them.

Features of the electrodes

The design features of the electrodes of the "Champion" candles are encrypted in the form of alphabetic characters. They are decoded as follows:

• A - electrodes of normal design;
• B - the candle has several side electrodes;
• C - the central electrode has a copper core;
• G - the central electrode is made of heat-resistant material;
• V - the design of the candle provides for a surface spark gap;
• X - the candle has a special design;
• CC - the side electrode has a copper core;
• BYC - the central electrode has a copper core, and in addition, the candle has two side electrodes;
• BMC - the ground electrode has a copper core, and the spark plug has three ground electrodes.

Spark gap

The gap between the electrodes in the labeling of Champion spark plugs is indicated by a number. namely:

• 4 - 1 mm;
• 5 - 1,3 mm;
• 6 - 1,5 mm;
• 8 - 2 mm.

Beru spark plug markings

Under the Beru brand, both premium and budget spark plugs are produced. However, in most cases, the manufacturer provides information about them in a standardized form - an alphanumeric code. It consists of seven characters. They are listed from right to left and tell the car owner the following information: candle diameter and thread pitch / candle design features / glow number / thread length / electrode design / main electrode material / candle body design features.

Thread diameter and pitch

The manufacturer provides this information in digital form.

• 10 - thread M10 × 1,0;
• 12 - thread M12 × 1,25;
• 14 - thread M14 × 1,25;
• 18 - thread M18 × 1,5.

Design features

What kind of spark plug has I take the design the manufacturer indicates in the form of letter codes:

• B - there is shielding, moisture protection and resistance to fading, and in addition, such candles have an electrode protrusion equal to 7 mm;
• C - similarly, they are shielded, waterproof, burn out for a long time and their electrode protrusion is 5 mm;
• F - this symbol indicates that the seat of the candle is larger than the nut;
• G - the candle has a sliding spark;
• GH - the candle has a sliding spark, and besides this, an increased surface of the central electrode;
• K - the candle has an o-ring for a conical mount;
• R - the design implies the use of a resistor to protect against radio interference;
• S - such candles are used for low-power internal combustion engines (additional information must be specified in the manual);
• T - also a candle for low-power internal combustion engines, but has an o-ring;
• Z - candles for two-stroke internal combustion engines.

Heat number

The manufacturer of Beru candles, the glow number of his products can be as follows: 13, 12,11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 09, 08, 07. The number 13 corresponds to a hot candle, and 07 - cold.

Thread length

The manufacturer indicates the length of the thread in literal form:

• A - thread is 12,7 mm;
• B - 12,7 mm regular or 11,2 mm with an o-ring for a cone mount;
• C — 19 mm;
• D - 19 mm regular or 17,5 mm with a cone seal;
• E - 9,5 mm;
• F - 9,5 mm.

Execution of the electrode design

Possible options:

• A - the ground electrode has a triangular shape on the ground;
• T is a multi-band ground electrode;
• D - the candle has two ground electrodes.

The material from which the central electrode is made

There are three options:

• U - the electrode is made of a copper-nickel alloy;
• S - made of silver;
• P - platinum.

Information about the special version of the spark plug

The manufacturer also provides the following information:

• O - the central electrode of the candle is reinforced (thickened);
• R - the candle has an increased resistance to burnout and will have a long service life;
• X - the maximum gap of the candle is 1,1 mm;
• 4 - This symbol means the spark plug has an air gap around its center electrode.

Spark Plug Interchange Chart

As mentioned above, all candles produced by domestic manufacturers are unified with imported ones. the following is a table that summarizes information on what products can replace popular domestic spark plugs for different cars.

Russia / USSR	Beru	BOSCH batteries and motors	BRISK	CHAMPION	MARELLI MAGNETS	NGK	NIPPON DENSO
А11, А11-1, А11-3	14-9A	W9A	N19	L86	FL4N	B4H	W14F
A11R	14R-9A	WR9A	NR19	RL86	FL4NR	BR4H	W14FR
A14B, A14B-2	14-8B	W8B	N17Y	L92Y	FL5NR	BP5H	W16FP
A14VM	14-8BU	W8BC	N17YC	L92YC	F5NC	BP5HS	W16FP-U
A14VR	14R-7B	WR8B	NR17Y	-	FL5NPR	BPR5H	W14FPR
A14D	14-8C	W8C	L17	N5	FL5L	B5EB	W17E
A14DV	14-8D	W8D	L17Y	N11Y	FL5LP	BP5E	W16EX
A14DVR	14R-8D	WR8D	LR17Y	NR11Y	FL5LPR	BPR5E	W16EXR
A14DVRM	14R-8DU	WR8DC	LR17YC	RN11YC	F5LCR	BPRX NUMXES	W16EXR-U
A17B	14-7B	W7B	N15Y	L87Y	FL6NP	BP6H	W20FP
A17D	14-7C	W7C	L15	N4	FL6L	B6EM	W20EA
А17ДВ, А17ДВ-1, А17ДВ-10	14-7D	W7D	L15Y	N9Y	FL7LP	BP6E	W20EP
A17DVM	14-7DU	W7DC	L15YC	N9YC	F7LC	BP6ES	W20EP-U
A17DVR	14R-7D	WR7D	LR15Y	RN9Y	FL7LPR	BPR6E	W20EXR
A17DVRM	14R-7DU	WR7DC	LR15YC	RN9YC	F7LPR	BPRX NUMXES	W20EPR-U
AU17DVRM	14FR-7DU	FR7DCU	DR15YC	RC9YC	7LPR	BCPR6ES	Q20PR-U
A20D, A20D-1	14-6C	W6C	L14	N3	FL7L	B7E	W22ES
A23-2	14-5A	W5A	N12	L82	FL8N	B8H	W24FS
A23B	14-5B	W5B	N12Y	L82Y	FL8NP	BP8H	W24FP
A23DM	14-5CU	W5CC	L82C	N3C	CW8L	B8ES	W24ES-U
A23DVM	14-5DU	W5DC	L12YC	N6YC	F8LC	BP8ES	W24EP-U

Hack and predictor Aviator

Deciphering the marking of spark plugs is a simple matter, but laborious. The above material will allow you to easily determine the technical parameters of products from most popular manufacturers. However, there are also many other brands in the world. in order to decipher them, it is enough to contact the official representative or ask for the relevant information on the official website of the manufacturer. If the trademark has neither an official representative nor an official website and there is little information about it in general, it is better to refrain from buying such candles altogether.