Crankshaft
The crankshaft is steel, forged, five-bearing, with four counterweights. The upper main bearing shells have oil grooves.
Main journals diameter, mm:
- nominal: 54.00-0,042-0,022;
- 1st repair size: 53.75-0,042-0,022;
- 2nd repair size: 53.50-0,042-0,022;
- 3rd repair size: 53.25-0,042-0,022.
Axial clearance of the crankshaft, mm:
- nominal: 0.07-0.18;
- maximum allowable: 0.20.
Gap between liners and main journals of the crankshaft, mm:
- nominal: 0.03-0.08;
- maximum allowable (during wear in operation): 0,17.
Diameter of connecting rod journals, mm:
- - nominal: 42.00-0,045-0,030;
- - 1st repair size: 41.75-0,045-0,030;
- - 2nd repair size: 41.50-0,045-0,030;
- - 3rd repair size: 41.25-0,045-0,030.
From September 1986, crankshafts with a modified nose were supplied as spare parts, with a groove for installing a toothed pulley. Accordingly, the segment key is abolished. When installing a new crankshaft, it is necessary to install a crankshaft sprocket with a locking pin and a redesigned oil pump, which, when installed, provides an increased clearance between its housing and the crankshaft sprocket. After applying engine oil to the thread, tighten the toothed pulley bolt in two steps:
- 1st reception: 9.0 kgf;
- Step 2: turn 180°.
It is recommended to press in the crankshaft front oil seal using the VW 3083 mandrel.
Pistons
Pistons are made of aluminum alloy with steel inserts. Each piston has two compression rings and one oil scraper ring. To install the piston in the cylinder, there is an arrow on the bottom of the piston, which must be directed towards the camshaft drive. The piston diameter is measured at a distance of 15 mm from the lower edge of the piston skirt at an angle of 90°relative to the axis of the piston pin. The deviation of the piston diameter from the nominal size in operation should not exceed 0.04 mm.
External diameter of pistons, mm:
- nominal: 74.98;
- 1st repair size: 75.23;
- 2nd repair size: 75.48;
- 3rd repair size: 75.98.
Piston pins
The piston pin is floating. From axial displacement, it is held by two retaining rings.
Piston pin length, mm: 58.
Piston rings
Three rings are installed on each piston: two compression and one oil scraper.
Gap in the lock, mm:
- compression rings: 0.3-0.45;
- oil scraper ring: 0.25-0.40.
Maximum allowable wear gap, mm: 1.0.
Gap between compression ring and piston groove, mm:
- nominal: 0.02-0.05;
- maximum allowable wear: 0.15.
Connecting rods
Connecting rods are steel, forged, with an I-section rod, with thin-walled liners. A bushing is pressed into the upper head of the connecting rod.
Clearance between liners and connecting rod journals of the crankshaft, mm:
- nominal: 0.02-0.076;
- maximum allowable wear: 0.095.
Axial clearance of the connecting rod on the neck of the crankshaft, mm:
- nominal: 0.05-0.31;
- maximum allowable wear: 0.40.
The diameter of the hole in the bushing of the upper head of the connecting rod, mm: 22.017-22.023.
Gap between piston pin and bushing, mm: 0.003-0.007.
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