Clear the piston of a deposit and remove all deposits from lubricant channels of the piston and a rod. Carefully examine all details. Cracks of any character on the piston, piston rings, a finger, on a rod and its cover are not allowed. If on them there are teases, scratches or wear tracks, these details it is necessary to replace. At piston survey:

Fig. 62. Gap measurement between piston rings and ring flutes in a piston head

- measure a gap between piston rings and ring flutes in a piston head by means of a set щупов (fig. 62) . The nominal gap for the top and bottom kompressionny rings makes 1 (fig. 63) 0,02 — 0,07 mm, and for maslosjemny 2 rings — 0,02 — 0,06 mm. Maximum permissible gaps at wear — 0,15 mm. If there is a gap, are worn-out either a ring, or a ring flute of the piston;

Fig. 63. Details of piston group: 1 — kompressionny piston rings; 2 — a maslosjemny ring; 3 — the piston; 4 — a rod cover; 5 — a bolt of fastening of a rod; 6 — rod loose leaves; 7 — a rod; 8 — the block of cylinders; 9 — a lock ring; 10 — a piston finger; the arrow A specifies the direction to a forward part of the engine

- in turn insert all piston rings, since bottom concerning a case into a cylinder opening. Having overturned one of pistons a reverse side, press through rings approximately on 15 mm down. After that they will appear directly in a cylinder opening;

Fig. 64. Measurement of a gap of locks of piston rings in a cylinder opening

- insert into cut of a piston ring — in the lock, measuring щуп to define a gap (fig. 64) . Kompressionny piston rings in the lock should have a gap 0,2 — 0,40 mm, and at a maslosjemny ring — 0,25 — 0,50 mm. A maximum permissible gap at wear at all rings — 1,0 mm;

- if the gap in the lock is too small (for example, at new piston rings which also should be measured), it needs to be increased. Rings are very fragile, therefore such work should be carried out carefully. It is best of all to clamp a file in a vice and to grind off the ring end;

- check on wear and teases piston fingers and plugs of rods. Even if only one rod has damages, it is necessary to replace all knot assembled;

- bolts of fastening of a rod on the VR6 engine are screwed up directly in rods (it is not used any nuts) and represent so-called «pliable screws» which it is necessary to replace after each untwisting;

- check rods by means of the measuring device on twisting and a bend.