Infiniti FX35, FX50 (S51). Manual - part 993

EM-272

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CYLINDER BLOCK

• Remove main bearing cap and bearings, and using the scale on

the plastigage bag, measure the plastigage width. 
NOTE:
The procedure when the measured value exceeds the limit is the
same as that described in the “Method by Calculation”.

MAIN BEARING CRUSH HEIGHT

• When main bearing cap is removed after being tightened to the

specified torque with main bearings (1) installed, the tip end of
bearing must protrude. Refer to 

EM-256, "Disassembly and

Assembly"

 for the tightening procedure.

• If the standard is not met, replace main bearings.

CONNECTING ROD BEARING CRUSH HEIGHT

• When connecting rod bearing cap is removed after being tightened

to the specified torque with connecting rod bearings (1) installed,
the tip end of bearing must protrude. Refer to 

EM-256, "Disassem-

bly and Assembly"

 for the tightening procedure.

• If the standard is not met, replace connecting rod bearings.

MAIN BEARING CAP BOLT OUTER DIAMETER

• Measure the outer diameters (A), (B) at two positions as shown in

the figure.

• If reduction appears in (A) range, regard it (B).

• If it exceeds the limit (large difference in dimensions), replace main

bearing cap bolts with new one.

MAIN BEARING CAP SUB BOLT OUTER DIAMETER

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A

: Crush height

Standard

: There must be crush height.

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A

: Crush height

Standard

: There must be crush height.

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c

: 20 mm (0.79 in)

d

: 40 mm (1.57 in)

e

: 12 mm (0.47 in)

Limit [(B) – (A)]

: 0.18 mm (0.0071 in)

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CYLINDER BLOCK

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E

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• Measure the outer diameters (A), (B) at two positions as shown in

the figure.

• If reduction appears in (A) range, regard it (B).

• If it exceeds the limit (large difference in dimensions), replace main

bearing cap sub bolts with new one.

CONNECTING ROD BOLT OUTER DIAMETER

1.

Measure the outer diameters [(a), (b) and (c)] at the position
shown in the figure.

2.

Obtain a mean value (d) of (a) and (b).

3.

Subtract (c) from (d).

4.

If it exceeds the limit (large difference in dimensions), replace the bolt with new one.

DRIVE PLATE

• Check drive plate and signal plate (A) for deformation or damage.

CAUTION:

• Never disassemble drive plate.
• Never place drive plate with signal plate facing down.
• When handling signal plate, take care not to damage or

scratch it. 

• Handle signal plate in a manner that prevents it from becom-

ing magnetized.

• If damage is found, replace drive plate.

OIL JET

• Check nozzle for deformation and damage.
• Blow compressed air from nozzle, and check for clogs.
• Using a clean plastic stick, press check valve in oil jet relief valve. Check that valve moves smoothly with

proper reaction force.

• If it is not satisfied, clean or replace oil jet.

c

: 20 mm (0.79 in)

d

: 50 mm (1.97 in)

e

: 9 mm (0.35 in)

Limit [(B) – (A)]

: 0.13 mm (0.0051 in)

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a

: Value at the end of the smaller diameter of the bolt

b

: Value at the end of the smaller diameter of the bolt [opposite side of (a)]

c

: Value of the smallest diameter of the smaller of the bolt

Limit [(d) – (c)]

: 0.09 mm (0.0035 in)

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B

: Ring gear

: Engine front

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HOW TO SELECT PISTON AND BEARING

HOW TO SELECT PISTON AND BEARING

Description

INFOID:0000000005245262

• The identification grade stamped on each part is the grade for the dimension measured in new condition.

This grade cannot apply to reused parts.

• For reused or repaired parts, measure the dimension accurately. Determine the grade by comparing the

measurement with the values of each selection table.

• For details of the measurement method of each part, the reuse standards and the selection method of the

selective fitting parts, refer to the text.

Piston

INFOID:0000000005245263

WHEN NEW CYLINDER BLOCK IS USED

Check the cylinder bore grade (“1”, “2” or “3”) on rear side of cylinder
block, and select piston of the same grade.

NOTE:
Piston is available with piston pin as a set for the service part.

WHEN NEW CYLINDER BLOCK IS REUSED

1.

Measure the cylinder bore inner diameter. Refer to 

EM-287, "Cylinder Block"

.

Selection points

Selection parts

Selection items

Selection methods

Between cylinder block and 
crankshaft

Main bearing

Main bearing grade
(bearing thickness)

Determined by match of cylin-
der block bearing housing 
grade (inner diameter of hous-
ing) and crankshaft journal 
grade (outer diameter of jour-
nal)

Between crankshaft and con-
necting rod

Connecting rod bearing

Connecting rod bearing grade 
(bearing thickness)

Determined by match of con-
necting rod big end diameter 
grade (inner diameter of hous-
ing) and crankshaft pin outer di-
ameter.

Between cylinder block and pis-
ton

Piston and piston pin assembly
(Piston is available together 
with piston pin as assembly.)

Piston grade
(piston skirt diameter)

Piston grade = cylinder bore 
grade (inner diameter of bore)

A

: Bearing housing grade No. 1

B

: Bearing housing grade No. 2

C

: Bearing housing grade No. 3

D

: Bearing housing grade No. 4

E

: Bearing housing grade No. 5

F

: Cylinder bore grade No. 1

G

: Cylinder bore grade No. 2

H

: Cylinder bore grade No. 3

I

: Cylinder bore grade No. 4

J

: Cylinder bore grade No. 5

K

: Cylinder bore grade No. 6

L

: Cylinder bore grade No. 7

M

: Cylinder bore grade No. 8

: Engine front

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HOW TO SELECT PISTON AND BEARING

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2.

Determine the bore grade by comparing the measurement with
the values under the cylinder bore inner diameter of the “PIS-
TON SELECTION TABLE”.

3.

Select piston of the same grade.

PISTON SELECTION TABLE

Unit: mm (in)

NOTE:
Piston is available together with piston pin as assembly.

Connecting Rod Bearing

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WHEN NEW CONNECTING ROD AND CRANKSHAFT ARE USED

1.

Apply connecting rod big end diameter grade stamped (D) on
connecting rod side face to the row in the “CONNECTING ROD
BEARING SELECTION TABLE”.

A

:  Bank  2

B

:  Bank  1

C

: Front mark

D

: Piston grade number

E

: Piston pin grade number

F

: Identification code

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Grade

1

2

3

Cylinder bore inner diameter

95.500 - 95.510

(3.7598 - 3.7602)

95.510 - 95.520

 (3.7602 - 3.7606)

95.520 - 95.530

(3.7606 - 3.7610)

Piston skirt diameter

95.480 - 95.490

(3.7590 - 3.7594)

95.490 - 95.500

(3.7594 - 3.7598)

95.500 - 95.510

(3.7598 - 3.7602)

A

:  Sample  codes

B

: Bearing stopper groove

C

: Small-end diameter grade

E

: Weight grade

F

: Cylinder No.

G

: Management code

H

:  Front  mark

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