Laying the crankshaft D-245

Before assembly, each crankshaft must be checked using a magnetic or ultrasonic flaw detector for the absence of micro and macro cracks; as well as the compliance of the selected set of main bearing shells with the size of the main journals

Mechanical damage (risks, dents, nicks, etc.) on the crankshaft journals and main bearing shells is not allowed.

Crank mechanism: 1 - bolt; 2 - crankshaft pulley; 3 - oil pump drive gear; 4 - drive gear; 5 - crankshaft; 6 - main journal liners; 7 - counterweight; 8 - connecting rod; 9 - connecting rod bushing; 10 - piston rings; 11 - piston; 12 - finger; 13 - retaining ring; 14 - half rings; 15 - flywheel; 16 - connecting rod journal liners

The main journals, shells and bearing seats should be wiped with a cloth and blown with compressed air.

The main bearing caps must fit tightly into the block sockets.

Rearranging or turning over the main bearing caps is not permitted.

Disassembly of the main bearing shells is not permitted.

Inserts must be installed in the corresponding sockets of the cylinder block.

The main journals and bearings must be lubricated with engine oil before installing the crankshaft.

The thrust half rings installed on the bed walls of the fifth main bearing and the bearing cap must be selected so that the longitudinal play of the crankshaft after tightening the main bearing bolts is 0.14-0.37 mm.

The valve mechanism crackers should protrude 0.5-2.0 mm above the plane of the washer;

In a set for one diesel engine, you must select pistons, connecting rods and piston pins of the same weight group; the weight of the connecting rods complete with pistons should not exceed 30 g.

Main and connecting rod journals and crankshaft bearing shells are manufactured in two nominal sizes.

Nominal dimensions of crankshaft journals:

  • Diameter of the shaft journal 1H - main journal - 75.25-0.083; connecting rod journal - 68.25-0.077;
  • Diameter of the shaft journal 2H - main journal - 75.00-0.083; connecting rod journal - 68.00-0.077

Nominal dimensions of crankshaft bearing shells:

  • The internal diameter of the BN1 liner - the main neck - 75.25-0.033 mm; connecting rod journal - 68.25+0.025 mm;
  • The internal diameter of the BN2 liner - the main neck - 75.00-0.033 mm; connecting rod journal - 68.00+0.025 mm

Crankshafts, the connecting rod and main journals of which are made according to the second nominal size, have an additional designation on the first cheek:

  • 2K - main journals of the second denomination;
  • 2Ш - connecting rod journals of the second rating;
  • 2КШ - connecting rod and main journals of the second rating.

Repair dimensions of crankshaft journals

The diameter of the shaft journal D1 - the main journal - 74.75-0.083 mm; connecting rod journal - 67.75-0.077 mm;

The diameter of the shaft journal P1 - the main journal - 74.50-0.083 mm; connecting rod journal - 67.50-0.077 mm;

Diameter of the shaft journal D2 - main journal - 74.25-0.083 mm; connecting rod journal - 67.25-0.077 mm;

The diameter of the shaft journal P2 - the main journal - 74.00-0.083 mm; connecting rod journal - 67.00-0.077 mm;

Diameter of the shaft journal D3 - main journal - 73.75-0.083 mm; connecting rod journal - 66.75-0.077 mm;

The diameter of the shaft journal P3 - the main journal - 73.50-0.083 mm; connecting rod journal - 66.50-0.077 mm;

Diameter of the shaft journal D4 - main journal - 73.25-0.083 mm; connecting rod journal - 66.25-0.077 mm;

The diameter of the shaft journal P4 - the main journal - 73.00-0.083 mm; connecting rod journal - 66.00-0.077 mm;

When checking the tightening of the main bearing cap bolts for additional tightening, the torque value should not exceed 240 Nm.

The tightening torque of the main bearing bolts should be 200-220 Nm.

In this case, the crankshaft should rotate smoothly, without jamming, with a torque of no more than 3 Nm.

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