3.8.8. Assembly of conrod and piston group
As the finger is implanted into the top head of a rod with a tightness, heat a rod to 240 °C for expansion of its head. For this purpose place rods in the electric furnace, directing the top heads of rods in the furnace.
Place in the furnace which is already heated to 240 °C, rods for 15 min.
For the correct connection of a finger with a rod, press a finger as soon as possible as the rod is cooled quickly and after cooling it will be impossible to change position of a finger.
Fig. 3-31. Installation of a piston finger on the A.60325 device for its press fitting in the piston and a head of a rod: 1 — adaptation roller; 2 — a piston finger; 3 — a guide; 4 — the persistent screw
In advance prepare a finger for assembly, having put on it the roller 1 (fig. 3-31) of A.60325 adaptation, having established on the end of this roller a guide 3 and having fixed it by the screw 4. Tighten the screw leaky that there was no jamming at expansion of a finger from contact with a heated rod.
Fig. 3-32. A press fitting of a piston finger in the top head of a rod: 1 — A.60325 adaptation; 2 — a piston finger. The piston has to lean on a rod head in the direction specified by an arrow
Quickly clamp the rod taken from the furnace in a vice. Put on the piston a rod, watching that the opening under a finger coincided with an opening of the top head of a rod. A.60325 adaptation, push the fixed piston finger in an opening of the piston and in the top head of a rod (fig. 3-32) so that the zaplechik of adaptation adjoined to the piston.
During this operation the piston has to nestle a lug on the top head of a rod in the direction of a finger press fitting (it is shown by an arrow in fig. 3-32). Thus the finger will reach the correct position.
After cooling of a rod oil a finger for the engine through openings in piston lugs.
If on the lower head of a rod there is an opening for an oil exit, then the piston has to connect to a rod so that the tag "П" on the piston and an opening on a rod were on the one hand.
Oil engine flutes on the piston and piston rings. Focus piston rings so that the lock of the top compression ring settled down at an angle about 45 ° to an axis of a piston finger, the lock of the lower compression ring — at an angle about 180 ° to an axis of the lock of the top compression ring, and the lock of an oil scraper ring — at an angle about 90 ° to an axis of the lock of the top compression ring.
Establish the lower compression ring by bore down (see fig. 3-25). If on a ring the tag "Top" or "TOP" is put, then establish a ring by a tag up (to the piston bottom).
Before installation of an oil scraper ring check that the joint of a spring dilator settled down from outside, opposite to the ring lock.
The rod is processed together with a cover and therefore covers of rods are not interchanged. That not to mix them at assembly, on a rod and the cover corresponding to it number of the cylinder in which they are established is branded. At assembly of figure on a rod and a cover have to be on the one hand.