3.8.4. Check of a gap between the piston and a finger

The finger is pressed in the top head of a rod with a tightness and freely rotates in piston lugs.

On outer diameter fingers are injured into three categories through 0,004 mm. The category is specified by a color tag at a finger end face: a blue tag — the first category, green — the second, red — the third.

Fig. 3-26. The piston finger has to be established by simple pressing of a thumb of a hand

Fig. 3-27. Check of landing of a piston finger

Interface of a piston finger and the piston check, implanting the finger which is previously oiled engine into a piston lug opening. It is necessary for the correct interface that the piston finger entered an opening from simple pressing of a thumb of a hand (fig. 3-26) and did not drop out of a lug (fig. 3-27) if to keep the piston with a piston finger in vertical position.
Replace the finger which is dropping out of a lug with another, the following category. If in the piston a finger of the third category, then the piston with a finger is replaced.