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

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).

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

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

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

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

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.

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).