The disassembly of the cylinder block was discussed in the article - “Disassembly of the cylinder block”.

After disassembling the cylinder block, it is necessary to determine the possibility of further use of the cylinder block, crankshaft and piston group.

Checking the block of cylinders

The non-flatness of the seating surface of the cylinder block is allowed no more than 0.03 mm. Grinding is not allowed.

Дефектация блока цилиндров двигателя К4М

The check must be carried out according to the scheme in Figure 1.

Determining the cylinder diameter

Дефектация блока цилиндров двигателя К4М

The distance X from the axis of the holes (1) to the seating surface of the cylinder block determines the group of cylinder diameters (for more details, see the table).

Mark (2) corresponds to cylinder no. 1, and mark (3) corresponds to cylinder no. 4 (see fig. 2).

Cylinder diameters

hole position, мм

size group label

cylinder diameter,

мм

Х=17

А

От 79,500 до 79,510

Х=27

В

От 79,510 до 79,520

Х=37

С

От 79,520 до 79,530

Main bearing diameters

The size of the diameters of the main bearing supports in the cylinder block is given in table 2. The size of the main bearing shells is given in table 3.

Diameters of openings of supports of radical bearings in the block of cylinders

hole position 2 и 3, мм

class label

crankshaft bearing diameter

Х1, мм

Х2=17

1

От 51,936 до 51,942

Х2=27

2

От 51,942 до 51,949

Main bearing shell sizes

Group

by diameter

holes

in the block

Size groups according to the diameter of the main journals and the thickness of the liners, mm

A or D

B or  E

C or  F

1

yellow label

C1=1,949­—1,955

blue mark

C1=1,946­—1,952

Black label

C1=1,943­—1,949

2

red label

C4=1,953­—1,959

yellow label

C1=1,949­—1,955

blue mark

C2=1,946­—1,952

Before checking, you need to install the crankshaft main bearing caps by installing cap No. 1 on the flywheel side.

Дефектация блока цилиндров двигателя К4М

After that, tighten the crankshaft main bearing cap bolts in the order shown in Figure 3.

We measure the diameters and remove the crankshaft main bearing caps.

Дефектация блока цилиндров двигателя К4М

The diameters (X1 figure 4) of the crankshaft bearings are marked by drilling in the area above the oil filter (Fig. 4 (B) in the direction of the arrow).

The position (X2) of the holes in relation to the seating surface of the cylinder block determines the diameter of the crankshaft bearings.

The crankshaft lies in the cylinder block on five bearings. Thrust semi-rings that regulate the axial clearance are installed on support No. 3.

Permissible parameters of the crankshaft:

Axial play of the crankshaft with new thrust half rings - 0.045 - 0.252 mm;

Axial play of the crankshaft with run-in thrust half rings - 0.027 - 0.054 mm.

Diametric clearance between the main journals of the crankshaft and bearings, mm - 0.027 - 0.054 mm.

Дефектация блока цилиндров двигателя К4М

Measuring the diameters of the crankshaft journals in Figure 5.

Size groups according to the diameter of the main journals

group

diameter of main journals mm

A/D

От 47,990 до 47,997

B/E

От 47,997 до 48,003

C/F

От 48,003 до 48,010

Size groups according to the diameter of the connecting rod journals:

group

Х3, мм

group

Х3, мм

A

43,960

O

43,971

B

43,961

P

43,972

C

43,962

R

43,973

D

43,963

S

43,974

E

43,964

T

43,975

F

43,965

U

43,976

G

43,966

V

43,977

H

43,967

W

43,978

J

43,968

Y

43,979

K

43,969

Z

43,980

L

43,970

 

 

When measuring, the minimum diameter along the perimeter of the neck is taken as the result.

Crankshaft marking

Дефектация блока цилиндров двигателя К4М

The location of the factory marking and marking information in Figure 6.

Tags carry the following information:

1 - size groups according to the diameter of the root necks;

2 - size groups according to the diameter of the main journal No. 1 from the flywheel side;

3 - size groups according to the diameter of the main journal No. 5 from the flywheel side;

4 - size groups according to the diameter of the connecting rod journals;

5 - size groups according to the diameter of the connecting rod journal No. 1 from the flywheel side.