The glow number of the candle is available in its alphanumeric code. The code is decrypted as follows.
Example: Bosch spark plug
- W - M14x1.25 thread with a flat sealing surface, 21 mm hexagon;
- F - M14x1.25 thread with a flat sealing surface, 16 mm hexagon;
- H thread M14x1.25 with a conical sealing surface, hexagon 16mm.
- Heat number - the scale of heat numbers changes from Ob («cold») up to 13 («hot»). In this case, the designation 8 corresponds to the old heat number 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 a strong protrusion. The thread length is indicated on plugs with a flat sealing surface.
- Additional letter T (for example, DT) indicates the three ground ground electrodes.
- The structure of the electrodes. Material of the central electrode: without designation - electrode with Cr-Ni alloying, C - central electrode made of Ni-Cu alloy, S - central electrode with silver coating, P - central electrode with platinum coating.
- R - with resistance to suppress interference. This does not affect the operation of the ignition system.
Type of spark plugs for BMW 7 series cars
Attention: Technological progress is ongoing. It may be that you can use candles of other brands. In this regard, it is recommended to consult a workshop about the applicability of a particular type of candle.
Technical data of the ignition system (DME)