5.16.2. Removal, repair and installation of conrod and piston group

It will be required to you: keys "on 10", "on 12", "on 14", heads "on 15", "on 19", the hammer.
1. Remove a head of the block of cylinders (see. "Replacement of laying of a head of the block of cylinders").
2. Remove an oil case of the engine and laying of a case (see. "Replacement of consolidation of an oil case").
3. Remove the oil pump (see. "Removal, repair and installation of the oil pump").
4. Turn off nuts of 1 conrod bolts and uncover 2 rods. If the cover sits densely, bring down it weak blows of the hammer. Take out an insert from a cover.
5. Push the piston that it went out of the cylinder, and take out it together with a rod. Take out an insert from a rod.

Notes
If you are going to establish former inserts, mark them with number of the cylinder.
It is necessary to take out the piston with a rod from the cylinder carefully not to damage a cylinder mirror. Check tags on a rod and a cover of a rod. If tags are not visible, mark a rod and a cover with number of the cylinder.

6. Take out other pistons with rods.
7. By means of a stripper remove piston rings, in the absence of a stripper carefully unbend rings at locks.

Prevention
Do not unbend a ring more, than it is required for their removal, otherwise violation of a form of rings or their breakage is possible.

8. Remove lock rings from two parties of the piston.
9. Vypressuyte special adaptation piston fingers. If there is no adaptation, it is possible to beat out piston fingers easy blows of the hammer through a mandrel 1, it needs to be done on weight not to damage the piston. Take out a rod 2 of the piston 3.
10. Remove other pistons from rods.
11. Wash out all details in gasoline. Clear pistons of a deposit. Clear of a flute deposit under piston rings a fragment of an old piston ring.
12. Examine pistons. If on them there are teases, traces of a progar, replace pistons. Measure diameter of the piston. If it is less than 95,4 mm, replace the piston. Diameter of the piston is measured in the plane, a perpendicular axis of a piston finger, its axes are 8,0 mm lower. The piston is installed in the cylinder with a gap of 0,036-0,060 mm. Pistons are broken on diameter into five dimensional groups: And, B, In. Alphabetic marking is beaten out on the piston bottom. At selection of the piston to the cylinder it is necessary to provide the gap stated above. A maximum permissible gap between the piston and the cylinder of 0,25 mm. The gap between the piston and the cylinder can be determined by measurement of the piston and cylinder. In spare parts deliver pistons of two repair sizes: with increased on 0,5 and with a diameter of 1,0 mm. On one of lugs under a piston finger the inscription is cast: "409" (the piston of nominal diameter), "409AP" (diameter increased by 0,5 mm) or "409BR" (diameter increased by 1,0 mm).
13. Measure a gap between a piston ring and a flute on the piston in several places on a piston circle. The gap has to be within 0,096–0,060 mm for compression rings and 0,115–0,365 mm for an oil scraper ring. If gaps exceed the specified values, rings or pistons need to be replaced.
14. Measure gaps in locks of piston rings. For this purpose insert a ring into the cylinder and advance the piston as a mandrel that the ring rose in the cylinder exactly, without distortions. Measure by the probe the gap in the lock (in the socket) rings, it has to be within 0,3–0,6 mm for compression rings and 0,5–1,0 mm for oil scraper disks. If the gap exceeds specified, replace a ring. If the gap is less, it is possible to saw round the ends of a ring the file clamped in a vice. At the same time move a ring on a file up-down.
15. Check landing of a piston finger in the top head of a rod. The gap between a finger and the plug of the top head of a rod has to be within 0,0045–0,0095 mm. Fingers, pistons and rods are injured into four dimensional groups and marked by paint. The finger is marked on an internal surface since one end, a rod — on a core, the piston — on the lower surface of one of lugs or beat out the Roman figure on the piston bottom. Dimensional groups of pistons, rods and fingers are brought in tab. 5.3.
Slightly oil a piston finger pure engine and insert into the top head of a rod. The finger has to enter a head from effort of a hand exactly, without jammings. The rod has to be turned on a piston finger under the influence of a body weight from horizontal position. In vertical position the finger should not move forward or drop out of a rod head under the influence of a body weight. The piston finger and a rod have to be one or next dimensional groups.

Table 5.3 Dimensional groups of pistons, rods and fingers of engines of fashion. ZMZ-409.10

16. Pistons with piston rings, fingers and rods assembled select for weight. The difference on weight for one engine has to be no more than 10 g.
17. Examine connecting rods. If on them there are teases, a vykrashivaniye and other defects, replace inserts.
18. Establish on rods of a cover and measure diameter of an opening in the lower head of a rod. Nominal diameter of an opening is 60+0,019 mm, maximum permissible – 60,03 mm. If the measured diameter exceeds maximum permissible, replace a rod with a cover. Measure diameter of an opening in the plug of the top head of a rod. Nominal diameter of an opening is 22+0,007 - 0,003 mm, maximum permissible – 22,01 mm. If the measured diameter exceeds maximum permissible, replace a rod. The sizes of conrod and piston group are specified in tab. 5.4.

Table 5.4 the Nominal and maximum permissible sizes and landing of the interfaced details of conrod and piston group of the engine of fashion. ZMZ-409.10
* The admission of 0,06 mm is broken into five groups (through 0,012 mm).

19. Collect the piston 4 with a rod 3. Previously heat the piston to temperature of 60-80 °C. Then quickly insert a rod into the piston so that the inscription "Before" on the piston and a ledge And on a rod were on the one hand, and press a piston finger 6 with the maximum tightness of 0,0025 mm. Establish lock rings 5. Put on by means of a stripper piston rings the piston.

Note
On the top compression ring there is an inscription "Top". The ring needs to be installed on the piston by this inscription to the piston bottom. On the lower compression ring from the inside there is a pro-point, the ring should be established by this pro-point to the piston bottom up.

Insert an insert 7 into the lower head of a rod, at the same time the fixing ledge ("lock") on an insert has to enter dredging in the lower head of the piston. Insert an insert 1 into a cover 2 rods, at the same time the fixing ledge ("lock") of an insert has to enter dredging in a cover. Grease the cylinder, the piston 4, a conrod neck of a bent shaft and inserts with 1 and 7 pure engine oil. Turn piston rings so that locks of compression rings settled down at an angle 180 ° to each other, locks of disks of an oil scraper ring — at an angle 180 ° to each other and at an angle 90 ° to locks of compression rings, the lock of a dilator of an oil scraper ring at an angle 45 ° to the lock of one of disks of an oil scraper ring. Turn a bent shaft so that the conrod neck of the cylinder in which install the piston was in the lower dead point (LDP). Insert the piston with a rod into the cylinder so that the inscription "Before" on a lug of the piston was turned to a forward part of the engine (to the drive of camshafts).

Good advice
Not to damage a cylinder mirror, it is recommended to put on conrod bolts of the plug from soft material (for example, scraps of rubber or plastic hoses).

By means of a special mandrel press out piston rings and easy blows by the handle of the hammer push the piston in the cylinder, at the same time the mandrel has to be densely pressed to the block, otherwise piston rings can be broken. Advance the piston down that the lower head of a rod sat down on a conrod neck of a bent shaft, and remove from conrod bolts of cutting of hoses. Establish a cover 2 rods on conrod bolts, the ledge of B on a cover of a rod has to be from the same party, as a ledge And on the lower head of a rod, numbers of cylinders which are beaten out on a rod and a cover have to be located on the one hand, and "locks" of inserts — against each other.
20. Wrap nuts of conrod bolts and tighten the moment 68–75 N · m (6,8–7,5 kgfs · м).
21. Similarly install other pistons with rods.
22. Several times turn a bent shaft, it has to rotate easily, without jammings.
23. Install the oil pump, an oil case and a head of the block of cylinders.