Distributor
Every 12,000 km, apply a thin film of Bosch 1 V 4 grease to the fiber pad (on the surface from the side of the axis) movable breaker contact. Remove the slider and put two drops of engine oil on the drive roller felt. With more oil, interruptions in ignition are possible.
The working surface of the breaker contacts must be completely clean. Adjust the gap between the contacts of the breaker, which should be within 0.35-0.40 mm on BMW «525», «528» and is equal to 0.40 mm on BMW «518», «520», «520i».
Setting the ignition timing
Every 15,000 km of run and after each adjustment of the gap between the contacts of the breaker, check the ignition timing.
Spark plug
Replace the spark plugs with new ones every 15,000 km.
Before installing new spark plugs, check the gap between the spark plug electrodes, which should be within 0.6 + 0.1 mm. It can only be adjusted by bending the side electrode.
It is allowed to unscrew the spark plugs from the cylinder head only with a special key.
Before installing spark plugs, lubricate their threaded part with a thin layer of graphite grease.