2.2.15.17. Piston check

ATTENTION The piston, piston ring and rod do not understand usual practice. At piston replacement the piston finger, a piston ring and a rod are replaced together, as a uniform element.

Fig. 2.162. Measurement of diameter of the piston

Measure external diameter of each piston at right angle 90 ° to a piston finger on 10,0 mm above the piston (fig. 2.162).

If diameter of the piston – is less than norm, replace the piston, a piston finger, a piston ring and a rod assembled.

Diameter of the L8 piston:

82,965–82,995 mm;

LF, L3, L3 (with the mechanism of change of phases of a gazoraspredeleniye):

87,465–87,495 mm.

Measure a gap between the piston and the cylinder.

If value does not correspond to norm, replace the piston, a piston finger, a piston ring and a rod assembled.

Normal gap: 0,025–0,045 mm.

Maximum gap: 0,11 mm.

Fig. 2.163. Gap measurement between a piston ring and a ring flute

Measure a gap between a piston ring and a ring flute on all circle of the piston (fig. 2.163).

If the gap exceeds maximum, replace the piston, a piston finger, a piston ring and a rod assembled.

Normal gap:

- the top: 0,03–0,08 mm;

- the second: on 0,03–0.07 mm;

- maslosjemny: 0,03–0.07 mm.

Maximum gap:

- the top: 0,17 mm;

- the second, maslosjemny: 0,15 mm.

Fig. 2.164. Measurement of a gap of a piston ring

Insert a piston ring into the cylinder and, pressing a ring the piston, displace it in the bottom point. Measure a gap in the lock of each piston ring shchupy (fig. 2.164).

If the gap exceeds maximum, replace the piston, a piston finger, a piston ring and a rod assembled.

Standard gap:

- the top: 0,16–0,31 mm;

- the second: 0,33–0,48 mm;

- maslosjemny: 0,20–0,70 mm;

- maximum gap: 1,0 mm.