Spark plugs (BMW 7 Series E32)

The spark plug consists of a middle electrode, an insulator with a housing and a ground electrode. Middle (central) the electrode is hermetically sealed in the insulator, and the insulator is tightly connected to the housing. The spark for igniting the fuel-air mixture jumps between the central and ground electrodes. Engine starting, idling, acceleration quality and engine power depend on spark plugs. Therefore, you should not deviate from the manufacturer's recommendations for choosing spark plugs. One of the main characteristics of spark plugs is the heat rating. The heat rating of a spark plug characterizes the thermal properties of the spark plug in an engine under certain operating conditions. Spark plugs for an engine are selected so that they reach the self-cleaning temperature under almost all engine operating conditions. The lower the heat rating of a spark plug, the higher its resistance to glow ignition and the lower its resistance to contamination. The higher the heat rating of a spark plug, the lower its resistance to glow ignition and the higher its resistance to contamination.

The glow plug's heat rating is contained in its alphanumeric code. The code is deciphered as follows.

Example: bosch spark plug

• W — thread M14x1.25 with flat sealing surface, 21 mm hexagon;
• F — thread M14x1.25 with flat sealing surface, 16 mm hexagon;
• H thread M14x1.25 with a conical sealing surface, hexagon 16 mm.
• Heat rating — the heat rating scale varies from 0.001 (cold) to 13 (hot). The designation 8 corresponds to the old heat rating of 150 (former designation), 7-175, 6-200, etc.
• B — thread length 12.7, spark trajectory with protrusion;
• C - thread length 19 mm, normal trajectory;
• D — thread length 19 mm, spark trajectory with protrusion;
• L — thread length 19 mm, spark trajectory with strong protrusion. Thread length value is indicated on spark plugs with a flat sealing surface.
• Additional letter T (for example, DT) indicates three side ground electrodes.
• Electrode design. Central electrode material: no designation — Cr-Ni alloyed electrode, C — Ni-Cu alloy central electrode, S — silver-coated central electrode, P — platinum-coated central electrode.
• R — with resistance for interference suppression. This does not affect the operation of the ignition system.

Spark plug type for BMW 7 series cars

Note: Technical progress is constant. It may be possible to use spark plugs of other brands. In this regard, it is recommended to consult with the workshop about the applicability of a particular type of spark plug.

Technical data of the ignition system (DME)