In the article, we will consider the preparation of the cylinder block, crankshaft and piston for engine assembly

Not allowed: cracks, breaks, dents, nicks, crumpling of edges, damage to the thread for more than two turns, the presence of signs of wear and work hardening on the teeth of the sprockets (visual inspection).

Invalid parts: Accessory belt, Timing chain, Timing chain tensioner, Timing chain tensioner boot, Timing chain guide, Cylinder head gasket, Cylinder head bolts, Camshaft dephaser filter , crankshaft pulley bolt, exhaust manifold stud nuts, exhaust manifold studs, oil filter, flywheel bolts, connecting rod cap bolts, crankshaft main bearing cap bolts, crankshaft main bearing shells, connecting rod bearing shells, drive chain oil pump, the oil pump chain tensioner must be replaced.

All sealing parts must be replaced

Cylinder block preparation

Crankshaft main journal bore diameter classes are shown in Table 1

Main journal diameter classes are indicated on the cylinder block, figure 1

fig. 1. Marking of the class of diameters of the main journals on the cylinder block: 1 - the place of marking the class of diameters of the main journals on the cylinder block, 2 - the diameter class of the main journal No. 1 on the timing drive side, 3 - the diameter class of the main journal No. 5 on the flywheel installation side

The maximum diameter "D" of the cylinders at which the replacement of the cylinder block is required is 78.10 mm.

fig. 2. Scheme for measuring the cylinder diameter: A, B - directions of measurements; a, b, c - measurement belts

Measure the cylinder diameter along three belts in the longitudinal and transverse directions, as shown in Figure 2.

The limit size is determined by the most worn cylinder using the NI 50-100-1 bore gauge

fig. 3. Measuring the flatness of the cylinder block

Using a straight edge and a set of feelers, we measure the non-flatness of the surface of the cylinder block mating with the head

We measure as shown in Figure 3

The maximum allowable flatness of the surface of the cylinder block mating with the cylinder head is 0.1 mm per 100 mm of length

Checking the booster of the cylinder block

We measure as shown in Figure 4

fig. 4. Checking the flatness of the mating surfaces of the cylinder block booster

The maximum flatness of the mating surfaces of the cylinder block booster on the cylinder block side and on the sump side is 0.1 mm per 100 mm length.

Crankshaft

fig. 5. Marking of the classes of diameters of the connecting rod and main journals of the crankshaft: 1 - size groups according to the diameter of the bearings of the connecting rod journals of the crankshaft, 2 - diameter class of the connecting rod journal on the timing drive side, diameter class of the connecting rod journal on the flywheel side, 4 - size groups according to the diameter of the main crankshaft journals, 5 is the diameter class of the main journal on the flywheel side, 6 is the diameter class of the main journal on the timing side

The marking of the size groups of the connecting rod and main journals of the crankshaft is applied on the flange for the installation of the flywheel, Figure 5.

We measure using a micrometer type MK 75-1

Crankshaft journal bore diameter classes

Letter on block

cylinders

denoting

diameters

indigenous

bearings

crankshaft

Hole diameter

main journals

crankshaft

in a block

cylinders, mm

A

51.997 - 51.998

B

51.998 - 51.999

С

51,999 - 52,000

D

52,000 - 52,001

E

52.001 - 52.002

F

52.002 - 52.003

G

52.003 - 52.004

N

52.004 - 52.005

J

52.005 - 52.006

K

52.006 - 52.007

L

52,007 - 52,008

M

52.008 - 52.009

N

52.009 - 52.010

R

52.010 - 52.011

R

52,011 - 52,012

S

52,012 - 52,013

T

52.013 - 52.014

U

52.014 - 52.015

V

52.015 - 52.016

W

52,016 - 52,017

Crankshaft journal diameter classes are shown in Table 2:

Letter, class

diameter

conrod journals

on crank

Vale

Diameters of the connecting rod journals of the crankshaft, mm

A

39.970 - 39.971

B

39.969 - 39.970

С

39.968 - 39.969

D

39.967 - 39.968

E

39,966 - 39,967

F

39.965 - 39.966

G

39,964 - 39,965

N

39.963 - 39.964

J

39,962 - 39,963

K

39.961 - 39.962

L

39.960 - 39.961

M

39,959 - 39,960

N

39.958 - 39.959

R

39,957 - 39,958

R

39.956 - 39.957

S

39,955 - 39,956

T

39,954 - 39,955

U

39,953 - 39,954

Classes of diameters of the main journals of the crankshaft are shown in table 3

Letter, diameter class

main journals

on crank

Vale

Diameters of the connecting rod journals of the crankshaft, mm

A

47,978 - 47,979

B

47,977 - 47,978

С

47,976 - 47,977

D

47,975 - 47,976

E

47,974 - 47,975

F

47,973 - 47,974

G

47,972 - 47,973

N

47,971 - 47,972

J

47,970 - 47,971

K

47,969 - 47,970

L

47,968 - 47,969

M

47,967 - 47,968

N

47,966 - 47,967

R

47,965 - 47,966

R

47,964 - 47,965

S

47,963 - 47,964

T

47,962 - 47,963

U

47,961 - 47,962

V

47,960 - 47,961

W

47,959 - 47,960

We check the radial runout of the crankshaft main journals using a prism, an indicator of the type ICH-10, a tripod ShM-PV-8

Radial runout should not exceed 0.01 mm

Piston preparation and inspection

Pistons are not allowed to have chips and cracks of any nature, burnouts, destruction of partitions

The outer diameter D, figure 5, of the piston, measured at a distance L=10 mm, should be 77.948 - 77.958 mm (micrometer type MK 100-1).

fig. 6. Checking the piston diameter

The diameter of the hole for the piston pin should be 19.008 - 19.014 mm (caliper type NI 18-50-1).

Checking the connecting rods

Diameter D, Figure 6, holes for the piston pin in the upper head of the connecting rod should be 18.958 - 18.978 mm (caliper type NI 18-50-1).

fig. 7. Checking the diameters of the holes in the upper and lower connecting rod heads

According to the diameter of the hole D1 in the lower head, the connecting rods are divided into several classes.

The connecting rod class and cylinder number are marked on the cap and on the connecting rod body.

Letter,

hole class

at the bottom

head

connecting rod

Hole diameters

at the bottom

head

connecting rod, mm

A

43.000 - 43.001

B

43.001 - 43.002

С

43,002 - 43,003

D

43,003 - 43,004

E

43,004 - 43,005

F

43.005 - 43.00b

G

43,006 - 43,007

N

43,007- 43,008

J

43,008 - 43,009

K

43,009 - 43,010

L

43,010 - 43,011

M

43,011 - 43,012

N

43.012 - 43.013

Classes of hole diameters in the lower head of the connecting rod are shown in Table 4 (bore gauge type NI 18-50-1)

Checking the thickness of the lower connecting rod head

The thickness of the lower head of the connecting rod must be within 18.748 - 18.800 mm (micrometer type MK 25-1).

Checking piston pins

Traces of wear and scuffing on the piston pins after pressing out (visual inspection) are not allowed.

Check the outside diameter of the piston pin.

The outer diameter of the piston pin must be between 18.996 - 18.998 mm (micrometer type MK 25-1).

Check piston pin length.

The length of the piston pin must be within 53.4 mm (caliper type ШЦ-1-125-0.1).

We covered the preparation of the cylinder head in a previous article