Contents: Spark plugs from BOSH ⇓ BERU candles ⇓
The spark plug consists of a central electrode, an insulator with a housing, and a ground electrode. The central electrode is installed in the insulator in a gas-tight manner. The insulator is firmly connected to the housing. An ignition spark jumps between the central and side electrodes, igniting the fuel-air mixture. The starting properties of the engine, the nature of idling, the throttle response of the car and its maximum speed depend on the spark plug. Therefore, it is not recommended to switch from the spark plugs recommended by the manufacturer to spark plugs of a different type without special reasons.
Thermal characteristics (heat rating) spark plug heat rating is an indicator of the degree of heat load of the spark plug in the engine under certain operating conditions. The lower the glow number of the spark plug, the higher its ability to withstand the heat load. The spark plug can better dissipate heat, thereby preventing damage due to pre-ignition (engine detonation). A spark plug with a high thermal load capacity has the disadvantage that its self-cleaning temperature is correspondingly higher. Such a spark plug is more prone to sooting, especially if the engine often does not reach its operating temperature during operation (urban cycle, short-distance driving in winter). As a rule, "cold" candles (with heat ratings starting from 06) are installed on "hot" engines, i.e. on power units that require more power.
The heat rating is contained in the spark plug designation. The spark plug designation is deciphered as follows:
Spark plugs from BOSH
Example:
W R 7 D C
1 2 3 4 5
1 - W = thread M 14x1.25 with flat sealing surface, SW 21;
F = thread M 14x1.25 with flat sealing surface, SW 16;
M = thread M 18x1.5 with flat sealing surface, SW 25;
H = thread M 14x1.25 with conical sealing surface, SW 16;
D = thread M 18x1.5 with conical sealing surface, SW 21;
SW = key size.
2 — R = with radio interference suppression resistor. Does not affect the operation of the ignition system.
3 — Heat rating. The heat rating scale is from 06 "cold" to 13 "warm". The heat rating value of 7 corresponds to 175 on the old scale, 6 — 200; 5 - 225 etc.
4 - A = thread length 12.7 mm, normal spark;
B = 12.7mm thread length, spark extended;
C = thread length 19 mm, normal spark;
D = thread length 19mm, stretched spark.
5 — Central electrode material: No designation = chromium-nickel alloy;
C = nickel-copper compound,
S = silver,
P = platinum,
O = standard spark plug with reinforced central electrode.
Due to the copper core in the central electrode, and to an even greater extent due to the silver central electrode, thermal conductivity is significantly increased.
BERU candles
Example:
14 R 7 D U
1 2 3 4 5
1 — thread diameter in mm, here M14 x 1.25
2 - design feature, for example, K for flat sealing surface, K for radio interference suppression resistor
3 — heat rating (like BOSH)
4 — thread length (like BOSH)
5 - electrode material, eg U for copper core
MAZDA models are usually equipped with NGK or Nippondenso spark plugs as standard. Standards vary among manufacturers. When replacing, BOSH and BERU spark plugs can be installed.