Mazda 323

since 1985 release

Repair and operation of the car

Spark plugs

The spark plug consists of the central electrode, the insulator with the case and a weight electrode. The central electrode is installed in the insulator gas-tightly. The insulator is strongly connected with the case. Between the central and side electrode the ignition spark igniting fuel-air mix slips. Starting properties of the engine, kind of work idling, acceleration performance of the car and its maximum speed depend on a spark plug. Therefore it is not recommended without the special reasons to pass from the candles recommended by manufacturer to candles of other type.

The thermal characteristic (kalilny number) of a candle is an exponent of thermal loading of a candle in the engine under certain conditions of operation. The kalilny number of a candle, the higher it ability to maintain thermal loading is lower. The candle can take away better heat at the expense of what damages because of kalilny ignition (an engine detonation) are prevented. The candle with high ability to maintain thermal loading has that shortcoming that its temperature of self-cleaning lies respectively above. Such candle is more inclined to a zakopcheniye, especially if the engine often does not reach the working temperature during the work (a city cycle, the movement by short pieces in the winter). As a rule, "cold" candles (with kalilny numbers since 06) are established on "hot" engines, i.e. on power units from which big power is required.

The Kalilny number contains in designation of a candle. Designation of a candle is deciphered as follows:

Spark plugs of BOSH

Example

W R 7 D C

1 2 3 4 5

1 — W = a carving of M 14x1,25 with a flat sealing surface, SW 21;

F = a carving of M 14x1,25 with a flat sealing surface, SW 16;

M = a carving of M 18x1,5 with a flat sealing surface, SW 25;

N = a carving of M 14x1,25 with a conic sealing surface, SW 16;

D = a carving of M 18x1,5 with a conic sealing surface, SW 21;

SW = key size.

2 — R = with the resistor of suppression of a radio noise. Does not exert impact on work of system of ignition.

3 — Kalilny number. A scale of kalilny numbers from 06 "cold" to 13 "warm". At the same time value of kalilny number 7 corresponds to value 175 on an old scale, 6 — 200; 5 — 225 etc.

4 — And = length of a carving is 12,7 mm, a normal spark;
In = length of a carving of 12,7 mm, the stretched spark;
With = length of a carving is 19 mm, a normal spark;
D = length of a carving of 19 mm, the stretched spark.

5 — material of the central electrode: Without designation = alloy of chrome and nickel;
With = compound of nickel and copper,
S = silver,
Р = platinum,
About = a standard candle with the strengthened central electrode.

At the expense of the copper core in the central electrode, and still more at the expense of a silver central electrode, heat conductivity considerably increases.

BERU candles

Example:

14 R 7 of D U

1 2 3 4 5

1 — diameter of a carving in mm, here M14 x 1,25

2 — a constructive sign, for example, To for a flat sealing surface, To for the resistor of suppression of a radio noise

3 — kalilny number (as at BOSH)

4 — carving length (as at BOSH)

5 — electrode material, for example U for the copper core

Serially the MAZDA models are in most cases equipped with the NGK or Nippondenso spark plugs. Norms at different producers differ. When replacing it is possible to establish candles of BOSH and BERU.