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4-9-3-2-1-podbor-porshnya-k-gilze-cilindrov.html
4.9.3.2.1. Selection of the piston to a sleeve of cylindersThe piston and the sleeve corresponding to it have to concern to one dimensional group (to have the same alphabetic index).
On outer diameter pistons are broken into five dimensional groups (And, B, In, E) through 0,01 mm.
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Group
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Color index
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Diameter of a sleeve, mm
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fashion. 331
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fashion. 3317 and 3313
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And
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Green
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81,95 – 81,94
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84,95 – 84,94
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B
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Yellow
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81,96 – 81,95
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84,96 – 84,95
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In
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Red
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81,97 – 81,96
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84,97 – 84,96
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Blue
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81,98 – 81,97
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84,98 – 84,97
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Д
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Black
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81,99 – 81,98
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84,99 – 84,98
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Alphabetic marking is applied on piston bottom surfaces.
The main thing at selection of the piston – to provide a necessary assembly gap between the piston and a sleeve.
At selection of new pistons to the worn-out cylinder the gap between a skirt of the piston and a mirror of a sleeve should be checked in the lower, least worn-out part of the cylinder. It is impossible to allow reduction of a gap in this part of the cylinder to value less than 0,02 mm. On weight pistons of one engine should not differ from each other more than on 3 g. Pistons are sorted at manufacturer by weight on four weight groups which marking (1, 2, 3, 4) is applied on the piston bottom. All pistons installed on one engine have to concern to one weight group.
After selection of pistons to sleeves is finished, it is necessary to pick up piston fingers to pistons and plugs of small heads of rods.
Landing of a piston finger in lugs of the piston can be ranging from 0,0025 mm of a tightness to 0,0025 mm of a gap. The gap between a piston finger and an opening of the plug of a head of a rod has to be within 0,0045–0,0095 mm.
Prevention
For simplification of selection of the corresponding sizes piston fingers, pistons and plugs of small heads of rods are sorted on four dimensional groups which diameters differ on 0,0025 mm. Each group has the color designation. Marking paint is applied: at the piston – on the lower surface of one of lugs, at a piston finger – on an internal surface since one end, on a rod – at a small head.
Interface of a piston finger and the plug of the top head of a rod check, implanting the finger which is previously oiled engine into a plug opening. It is necessary for the correct interface that the rod was turned on a finger from horizontal position under the influence of a body weight, but at the same time the finger implanted into the plug should not drop out of it under the influence of a body weight if to put a finger in vertical position. At the same time it is allowed to complete rods with fingers of adjacent group (towards reduction of a gap) on condition of observance of above-mentioned requirements.
In all cases selection of piston fingers to rods needs to be made indoors with the air temperature (20±3) °C.
Prevention
In case of replacement of one of rods it has to be picked up not only for the size of the plug of a small head, but also for weight. A difference in the mass of the heaviest and easiest rods in the set installed on one engine should not exceed 8 g. The rod belonging to one group on weight is marked its cover, risky on inflow.
To oil the picked-up finger engine. To heat the piston, having lowered it in a vessel with the water having temperature of 45-75 °C to implant a finger into openings of lugs of the piston and plug of a small head of a rod. To insert lock rings of a piston finger into flutes of lugs of the piston.
Prevention
The rod is processed assembled with a cover and therefore covers of rods are not interchanged.
The sets of pistons with fingers, lock and piston rings delivered in spare parts
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Designation of a set for the engine
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Name
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Outer diameter of a skirt of the piston, mm
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mod.331
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mod.3317
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mod.3313
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mod.331
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mod.3317 and 3313
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| 331.1004950 | 3317.1004950 | 3313.1004950 | The piston, finger, lock and piston rings (a set on 1 cylinder of the nominal size) | 81.94 – 81.99 | 84.94 – 84.99 |
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331.1004951
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3317.1004951
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3313.1004951
| The piston, finger, lock and piston rings (a set on 1 engine increased by 0,5 mm) | 82.44 – 82.49 | 85.44 – 85.49 |
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331.1004951 – 10
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3317.1004951 – 10
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| The same, increased by 1,0 mm | 82.94 – 82.99 | 85.94 – 85.99 |
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