Boring and honing cylinder bores

AR01.40-B-9291C

Boring and honing cylinder bores

07.02.2020

Engine

924.9 in model 368.0/1, 384.06/07, 685.282/284/289/290, 979.2

Engine

924.929 in model 384.3

Engine

926.9 in model 368.0/1, 382.1, 384.06/07, 634.0

1

Engine block

2

Cylinder

A

Engine block height

a

Chamfer on cylinder top edge



Remove

1

Remove the crankshaft

.

AR03.20-B-4351A

2

Remove the oil injectors from the pistons

.

AR18.00-B-4000E

Machining

3

Secure the engine block (1) in the boring machine

4

Centralize the cylinder (2) to be machined, with regard to the grinding machine

 Observe the work sequence to avoid overheating damage: 4-cylinder engines; 2-4-1-3 and 6-cylinder engines; 1-3-5-2-4-6.

5

Set the tool and carry out the machining of the cylinder

 The machining must be carried out in various stages until reaching a diameter of 0,05 mm smaller than the final diameter.

 Boring machine setting values:
Rotation; 250 - 280 / min (rpm)
Tool drive; 0,04 - 0,06 mm / turn.

.Cylinder's internal diameter, finishing

*BE01.40-B-1001-02C

6

Rectify the block surface at a height corresponding to the degree of the cylinders diameter

AR01.40-B-9133C

 The block height (A) must meet the tolerance degree of the cylinder's diameter (normal, repair I, repair II or repair III).

7

Polish the cylinder (2) until obtaining the desired diameter (finishing)

 Honing machine setting values:
Work pressure; 2.5 - 3.0bar.
Rotation; 60 - 100/min (rpm).
Honing angle; 40°- 60°.
Double stroke; 30 - 40 / min.

.Cylinder's internal diameter, finishing

*BE01.40-B-1001-02C

.Out of round and taper in the cylinder/deviation from the cylinder's travel (with liner and without liner)

*BE01.40-B-1002-02C

.Maximum admissible wear at the sliding surface of the cylinders (with and without liners)

*BE01.40-B-1003-02C

.Roughness (R3Z) cylinder barrel

*BE01.40-B-1004-02C



Clean

8

Clean the engine block



Install

9

Install the piston's oil injectors

.

AR18.00-B-4000E

10

Install the crankshaft

.

AR03.20-B-4351A

Engine block test values

Number

Designation

Engine 924.9, 926.9

BE01.40-B-1001-02C

Cylinder's internal diameter, finishing

Normal

Tolerance A

mm

105,985...105,991

Tolerance B

mm

105,992...106,008

Tolerance C

mm

106,009...106,015

Repair I

Tolerance A

mm

106,285...106,291

Tolerance B

mm

106,292...106,308

Tolerance C

mm

106,309...106,315

Repair II

Tolerance A

mm

106,585...106,591

Tolerance B

mm

106,592...106,608

Tolerance C

mm

106,609...106,615

Repair III

Tolerance A

mm

106,885...106,891

Tolerance B

mm

106,892...106,908

Tolerance C

mm

106,909...106,915

Engine block test values

Number

Designation

Engine 924.9, 926.9

BE01.40-B-1002-02C

Out of round and taper in the cylinder/deviation from the cylinder's travel (with liner and without liner)

contact surface

mm

0,012

Engine block test values

Number

Designation

Engine 924.9, 926.9

BE01.40-B-1003-02C

Maximum admissible wear at the sliding surface of the cylinders (with and without liners)

At the reversion point of the first piston ring

mm

0,1

At the center of the cylinder

mm

0,05

Engine block test values

Number

Designation

Engine 924.9, 926.9

BE01.40-B-1004-02C

Roughness (R3Z) cylinder barrel

micron

2,5...4,0