Spark plugs (BMW 3 Series E36)

The spark plug consists of a central electrode, an insulator with a housing, and a ground electrode. The ground electrode is hermetically secured in the insulator, and the insulator is rigidly connected to the housing. A spark jumps between the central electrode and the ground electrode, which ignites the air-fuel mixture. The ease of starting the engine, its behavior in idle mode, acceleration, and maximum speed of the car depend on the spark plugs. Therefore, you should not deviate from the type of spark plugs recommended by the manufacturer without good reason, which is characterized by a heat rating. The heat rating is the degree of resistance of the spark plug to thermal loads in the engine under various operating conditions. Spark plugs are selected for the engine in such a way that their self-cleaning temperature is achieved under all conditions. The lower the heat rating of the spark plug, the higher the resistance to glow ignition and the less its resistance to contamination. The higher the heat rating of the spark plug, the lower the resistance to glow ignition and the greater its resistance to contamination.

The heat rating is contained in the spark plug designation. The designation is deciphered as follows:

Spark plugs BOSCH

Example



1 W = thread M14x1.25 with flat sealing surface, key size 21 mm; F = thread M14x1.25 with flat sealing surface, key size 16 mm; M = thread M18x1.5 with flat sealing surface, key size 25 mm; H = thread M14x1.25 with conical sealing surface, key size 16 mm; D = thread M18x1.5 with conical sealing surface, key size 21 mm;



2 Heat rating. The heat rating scale ranges from 06 ("cold") to 13 ("hot"). The number 7 corresponds to the previous designation 175, 6 - 200.5-225, etc.

3A = thread length 12.7mm, normal spark position; B = thread length 12.7 mm, extended spark position; C = thread length 19 mm, normal spark position; D = thread length 19 mm, extended spark position; DT = thread length 19 mm, extended spark position, 3 earth electrodes; L = thread length 19 mm, significantly advanced spark position;

4 = Center Electrode Material. Cr-Ni alloy (Cr-Ni = chromium-nickel), C = Ni-Cu alloy (Ni-Cu = nickel-copper), S = Silver center electrode, P = Platinum center electrode - Standard spark plug with reinforced center electrode.

5 R = 1 kOhm, quenching resistance.

BERU spark plugs

Example



1 Thread diameter, here M14x1.25

2 F= flat fit, K – conical fit.

3 Heat rating, the decoding is the same as for Bosch spark plugs.

4 Thread length, decoding is the same as for Bosch spark plugs.

5 Central electrode material: U = ultra (Ni-Cu alloy), S = silver center electrode, P = platinum center electrode, O = reinforced center electrode.



6 R = 1 kOhm, quenching resistance

Recommended spark plugs for BMW 3-series vehicles produced since September 1990.

¹Non-adjustable triangular ground electrode.

Note: Due to constant technical progress, it may be that other types of spark plugs can be installed on older vehicles. Therefore, it is recommended to obtain information about the admissibility of installing a particular type of spark plug at a service station.