Note.
- On rings that have been in use, the marking may not be visible. Place the removed rings in the sequence of numbering of cylinders and positions.
- Install new pistons only with new piston rings.
Replacing piston rings must be carried out in the order given for the engine «M54», the following must be taken into account.
The axial clearance of the compression rings should be 0.020–0.070 mm for the first ring, and 0.020–0.060 mm for the second ring; measurements are not made for the oil scraper ring.
The gap in the lock of the compression rings, for all engines, should be 0.10–0.30, the oil scraper ring - 0.20–0.90 mm.
The oil scraper ring consists of two flat steel discs (1, fig.89) and one spring (2).
Insert spring (2) into the ring groove and then install the steel discs (1). Separate the locks of the rings in different directions at an angle of 120°relative to each other, while the joints of the rings should not be above the bosses of the piston pins.