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The connecting rod-piston group
The pistons are made of aluminum alloy, have a flat bottom and three grooves for rings. According to the diameter of the pistons are divided into three groups for a nominal size and two groups for the repair size (Table 2.2.).
Table 2.2 Dimensional groups of pistons Bore mm | Engine model | GA14DE | GA16DE | SR20DE | 1 th group of nominal size | 73,575-73,585 | 75,975-75,985 | 86,00-86,01 | Group 2 nominal size | 73,585-73,595 | 75,985-75,995 | 86,01-86,02 | Group 3 nominal size | 73,595-73,605 | 75,995-76,005 | 86,02-86,03 | Repair group -t-0,5 | 74,075-74,105 | 76,475-76,505 | - | Repair Group 0.1 | 74,575-74,605 | 76,975-77,005 | - | Repair Group 0.2 | - | - | 86,18-86,21 |
Dimensional groups of numbers labeled on the bottom of the piston. Pistons repair sizes are intended for installation in the engine block after boring. The label on the bottom of the piston should be facing toward the timing. The diameter of the holes in the lugs of a piston pin, mm: Engine GA 18,987-18,999 Engine SR 21,987-21,999 The clearance between the cylinder bore and the piston is in mm: Engine GA 0,015-0,035 Engine SR 0,01-0,03 Piston fingers hollow, steel, hardened and ground, rotate freely in the sleeve of a rod and a little effort are pressed in a cold state in the hole of the piston bosses. From the axial movement of the finger is held by two snap rings. The diameter of the piston pin, mm: GF 18,989-19,001 engines Engine SR 21,989-22,001 Interference in the bore of the piston boss 0-0,004 mm. The clearance between the piston pin and connecting rod sleeve top 0,005-0,017 mm.
| Fig. 2.4. Installation of the piston rings: I - how to install the piston rings; II - the location of the piston rings; 1 - label on the piston directed towards the timing; 2 - joint expander oil ring; 3 - lock the upper compression and oil scraper ring of the upper; 4 - Castle oil ring; 5 - lock lower compression ring
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Each piston set of three rings (Fig. 2.4): upper compression chrome, with a barrel surface; lower compression scraped; scraper with a speculum, the upper and lower rings. The clearance between the piston rings and the piston grooves is: - To the top of the ring - 0.04-0.08 mm, the maximum allowable 0.2 mm; - To lower the rings - 0,03-0,07 mm, the maximum allowable 0.2 mm. The gap in the castle: - To the top of the ring - 0.2-0.35 mm; maximum permissible engine GA - 1 mm; maximum permissible engine SR - 0,49 mm; - To lower the rings - 0,37-0,52 mm; maximum permissible engine GA - 1 mm; maximum permissible engine SR - 0,64 mm; - For the oil scraper ring - 0.2-0.6 mm; maximum permissible engine GA - 1 mm; maximum permissible engine SR - 1,09 mm. Connecting rods Steel forged, I-section, the bottom head of a rod with a straight connector. When you install the label on the cover of the bottom head of a rod located opposite the mark on the connecting rod; lubrication hole is oriented toward the starter. The distance between the centers of the holes of the upper and lower heads, connecting rod engines GA is 140,45-140,55 mm. The hole diameter of the bottom head of a rod, mm: GA 43,000-43,012 engines SR 51,000-51,013 engines The diameter of the sleeve hole upper crosshead, mm: GA 19,000-19,012 engines SR 22,000-22,012 engines
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