2.8.16. Conrod and piston group

Fig. 2.374. Components of the piston and rod: 1 – a bolt of fastening of a cover of a rod – 30 N · + to tighten m on +90 ° (1/4 about.); 2 – rod cover; 3 – bearing insert; 4 – rod; 5 – piston finger; 6 – lock ring; 7 – piston; 8 – piston rings



Check of a thermal gap of piston rings

Fig. 2.133. Check of a thermal gap of a piston ring


Insert a ring from above, at right angle to a cylinder wall, to the lower opening of the cylinder, at distance about 15 mm from its edge. For this purpose use the piston without rings (fig. 2.133).


Check of a gap of piston rings on height

Fig. 2.375. Check of a gap of piston rings on height


Before check clear a ring flute of the piston (fig. 2.375).


Check of pistons
Measure by means of a micrometer for external measurements 75–100 mm approximately in 10 mm from bottom edge, at right angle to an axis of a piston finger.
The maximum deviation from the nominal size: 0,04 mm

Check of diameter of the cylinder
By means of a precision nutromer of 50-100 mm measure in 3 places cross-wise in the cross direction A and the longitudinal direction B

Fig. 2.135. Scheme of check of diameter of the cylinder

(fig. 2.135).
The maximum deviation from the nominal size: 0,08 mm

Provision of installation and compatibility piston / cylinder

Fig. 2.376. Tags on the piston bottom


Mark adjusting situation and belonging to the cylinder with chalk or a waterproof felt-tip pen on the bottom of the piston (fig. 2.376).

NOTE
Do not use a center punch or a chertilka not to damage a piston bottom covering.

Adjusting situation: the arrow indicates the bottom of the piston towards belt pulleys.

Fig. 2.377. Adjusting tags on rods


Mark rods (fig. 2.377).

NOTE
Replace rods only with a set.
Do not interchange the position of conrod bearings.
Before removal mark with paint rods and conrod covers on the relation to each other and to the cylinder.

Adjusting provision of rods

Fig. 2.378. The direction of toes on the ground surfaces of couples of rods


Toes on the ground surfaces of couples of rods 1 and 2, 3 and 4. and also has to be 5 and 6 are turned at each other (fig. 2.378).

Sizes of pistons and cylinders
* The sizes with a covering (thickness of 0,02 mm). The covering wears out.