Press out piston pin by hand.
Remove piston.
Carefully remove piston rings with piston ring pliers.
Remove combustion residues from piston crown and clean piston.
Caution! Do not mix up pistons, piston pins and piston rings.
Checking pistons and cylinders
Reference temperature for measurements: 20°C (68°F)
![](https://motoinstruction.ru/img/bmw/6/113864.jpg)
Measure cylinder bore with internal probe at 20 mm (0.79 in) and 100 mm (3.94 in) from the top in direction of piston pin, and again at a right angle to the first measurement. See Technical Data.
![](https://motoinstruction.ru/img/bmw/6/113865.jpg)
Measuring plane A: 6 mm (0.236 in). See Technical Data.
Install piston rings in cylinder.
![](https://motoinstruction.ru/img/bmw/6/113867.jpg)
Measure ring gap using feeler gauge. See Technical Data.
Assembling pistons
![](https://motoinstruction.ru/img/bmw/6/113866.jpg)
Carefully fit piston rings to piston in the following sequence, using piston ring pliers:
- 3rd groove - coiled-spring ring
- 2nd groove - micro-chamfer ring
- 1st groove - asymmetric piston ring, oval section. See Technical Data
Note: Make sure that the gap of the spring is offset approximately 180° from the gap of the oil control ring. Install with «TOP» uppermost.