Infiniti G37 Coupe. Manual - part 637

 

  Index      Infiniti     Infiniti G37 Coupe - service repair manual 2008 year

 

Search            

 

 

 

 

 

 

 

 

 

Content   ..  635  636  637  638   ..

 

 

Infiniti G37 Coupe. Manual - part 637

 

 

CYLINDER BLOCK

EM-123

< DISASSEMBLY AND ASSEMBLY >

C

D

E

F

G

H

I

J

K

L

M

A

EM

N

P

O

Measure the outer diameter of piston pin with a micrometer (A).

Connecting Rod Bushing Oil Clearance

(Connecting rod bushing oil clearance) = (Connecting rod bushing inner diameter) – (Piston pin outer diame-
ter)

• If the calculated value exceeds the limit, replace connecting rod assembly and/or piston and piston pin

assembly.

• If replacing piston and piston pin assembly, refer to 

EM-131, "Description"

.

• If replacing connecting rod assembly, refer to 

EM-132,

"Connecting Rod Bearing"

 to select the connecting rod bearing.

Factory installed parts grading:

• Service parts apply only to grade “0”.

Unit: mm (in)

*: After installing in connecting rod

CYLINDER BLOCK DISTORTION

Standard

: Refer to 

EM-143, "Cylinder Block"

.

JPBIA0218ZZ

Standard and limit

: Refer to 

EM-143, "Cylinder Block"

.

A

:  Sample  codes

B

: Bearing stopper groove

C

: Small-end diameter grade

D

: Big-end diameter grade

E

: Weight grade

F

: Cylinder No.

G

: Management code

H

: Front mark

I

: Management code

JPBIA0208ZZ

A

:  RH

B

:  LH

C

: Piston pin grade number

D

: Piston grade number

E

: Front mark

F

: Identification code

               Grade

                    0

                    1

Connecting rod bushing 
inner diameter *

         22.000 - 22.006          
       (0.8661 - 0.8664)

         22.006 - 22.012
        (0.8664 - 0.8666)

Piston pin hole diameter

        21.993 - 21.999
       (0.8659 - 0.8661)

         21.999 - 22. 005
        (0.8661 - 0.8663)

Piston pin outer diameter

        21.989 - 21.995
       (0.8657 - 0.8659)

         21.995 - 22.001
        (0.8659 - 0.8662)

JPBIA1212ZZ

EM-124

< DISASSEMBLY AND ASSEMBLY >

CYLINDER BLOCK

• Using a scraper, remove gasket on the cylinder block surface, and also remove engine oil, scale, carbon, or

other contamination. 

CAUTION:

Be careful not to allow gasket flakes to enter engine oil or engine coolant passages.

• Measure the distortion on the cylinder block upper face at some

different points in six directions (C, D, E, F, G and H) with a
straightedge (A) and a feeler gauge (B).

• If it exceeds the limit, replace cylinder block.

MAIN BEARING HOUSING INNER DIAMETER

• Install lower cylinder block (2) without installing main bearings, and

tighten lower cylinder block bolts to the specified torque. Refer to

EM-111, "Disassembly and Assembly"

 for the tightening proce-

dure.

• Measure the inner diameter of main bearing housing with a bore

gauge.

• If out of the standard, replace cylinder block (1) and lower cylinder

block as assembly.
NOTE:
Cylinder block cannot be replaced as a single part, because it is
machined together with lower cylinder block.

PISTON TO CYLINDER BORE CLEARANCE

Cylinder Bore inner Diameter 

• Using a bore gauge, measure cylinder bore for wear, out-of-round

and taper at six different points on each cylinder. [(A) and (B) direc-
tions at (C), (D) and (E)] is in longitudinal direction of engine.

• If the measured value exceeds the limit, or if there are scratches

and/or seizure on the cylinder inner wall, hone or re-bore the inner
wall. 

• Oversize piston is provided. When using oversize piston, re-bore

cylinder so that the clearance of the piston-to-cylinder bore satis-
fies the standard.

CAUTION:

When using oversize piston, use oversize pistons for all cylin-
ders with oversize piston rings.

Piston Skirt Diameter

Limit

: Refer to 

EM-143, "Cylinder Block"

.

JPBIA0224ZZ

Standard

: Refer to 

EM-143, "Cylinder Block"

.

JPBIA0225ZZ

f

: 10 mm (0.39 in)

g

: 60 mm (2.36 in)

h

: 125 mm (4.92 in)

Standard and limit

: Refer to 

EM-143, "Cylinder Block"

.

JPBIA0226ZZ

Oversize (O/S)

: 0.2 mm (0.008 in)

SEM843E

CYLINDER BLOCK

EM-125

< DISASSEMBLY AND ASSEMBLY >

C

D

E

F

G

H

I

J

K

L

M

A

EM

N

P

O

Measure the outer diameter of piston skirt with a micrometer (A).

Piston-to-Cylinder Bore Clearance

Calculate by piston skirt diameter and cylinder bore inner diameter [direction (B), position (D)].
(Clearance) = (Cylinder bore inner diameter) – (Piston skirt diameter).

• If the calculated value exceeds the limit, replace piston and piston pin assembly. Refer to 

EM-143,

"Cylinder Block"

.

Re-boring Cylinder Bore

1.

Cylinder bore size is determined by adding piston to cylinder bore clearance to piston skirt diameter.

2.

Install lower cylinder block, and tighten to the specified torque. Otherwise, cylinder bores may be distorted
in final assembly.

3.

Cut cylinder bores.
NOTE:
• When any cylinder needs boring, all other cylinders must also be bored.
• Do not cut too much out of cylinder bore at a time. Cut only 0.05 mm (0.0020 in) or so in diameter at a

time.

4.

Hone cylinders to obtain the specified piston to cylinder bore clearance.

5.

Measure finished cylinder bore for the out-of-round and taper.
NOTE:
Perform measurement after cylinder bore cools down.

CRANKSHAFT MAIN JOURNAL DIAMETER

• Measure the outer diameter of crankshaft main journals with a micrometer.

• If out of the standard, measure the main bearing oil clearance. Then use undersize bearing. Refer to 

EM-

135, "Main Bearing"

.

CRANKSHAFT PIN JOURNAL DIAMETER

Measure point 

: Refer to 

EM-143, "Cylinder Block"

.

Standard

JPBIA0227ZZ

Standard and limit

: Refer to 

EM-143, "Cylinder Block"

.

Re-bored size calculation: D = A + B – C

where,

D: Bored diameter

A: Piston skirt diameter as measured

B: Piston to cylinder bore clearance (standard value)

C: Honing allowance 0.02 mm (0.0008 in)

Standard

: Refer to 

EM-143, "Cylinder Block"

.

EM-126

< DISASSEMBLY AND ASSEMBLY >

CYLINDER BLOCK

• Measure the outer diameter of crankshaft pin journal with a

micrometer (A).

• If out of the standard, measure the connecting rod bearing oil

clearance. Then use undersize bearing. Refer to 

EM-132,

"Connecting Rod Bearing"

.

CRANKSHAFT OUT-OF-ROUND AND TAPER

• Measure the dimensions at four different points as shown in the

figure on each main journal and pin journal with a micrometer. 

• Out-of-round is indicated by the difference in the dimensions

between (d) and (C) at (a) and (b).

• Taper is indicated by the difference in the dimensions between.

• If the measured value exceeds the limit, correct or replace crank-

shaft.

• If corrected, measure the bearing oil clearance of the corrected

main journal and/or pin journal. Then select the main bearing and/
or connecting rod bearing. Refer to 

EM-135, "Main Bearing"

 and/

or 

EM-132, "Connecting Rod Bearing"

.

CRANKSHAFT RUNOUT 

• Place V-block on precise flat table, and support the journals on

both ends of crankshaft.

• Place a dial indicator straight up on the No. 3 journal.
• While rotating crankshaft, read the movement of the pointer on a

dial indicator. (Total indicator reading)

• If it exceeds the limit, replace crankshaft.

CONNECTING ROD BEARING OIL CLEARANCE

Method by Calculation

• Install connecting rod bearings (1) to connecting rod (2) and con-

necting rod cap, and tighten connecting rod bolts to the specified
torque. Refer to 

EM-111, "Disassembly and Assembly"

 for the

tightening procedure.

• Measure the inner diameter of connecting rod bearing with an

inside micrometer.

(Oil clearance) = (Connecting rod bearing inner diameter) – (Crank-
shaft pin journal diameter)

• If the calculated value exceeds the limit, select proper connecting

rod bearing according to connecting rod big end diameter and
crankshaft pin journal diameter to obtain the specified bearing oil clearance. Refer to 

EM-131, "Description"

.

Method of Using Plastigage

• Remove oil and dust on crankshaft pin journal and the surfaces of each bearing completely. 
• Cut a plastigage slightly shorter than the bearing width, and place it in crankshaft axial direction, avoiding oil

holes.

Standard

: Refer to 

EM-143, "Cylinder Block"

.

JPBIA0228ZZ

Limit

: Refer to 

EM-143, "Cylinder Block"

.

JPBIA0229ZZ

Standard and limit

: Refer to 

EM-143, "Cylinder Block"

.

SEM346D

Standard and limit

: Refer to 

EM-147, "Main Bearing"

.

JPBIA0230ZZ

 

 

 

 

 

 

 

Content   ..  635  636  637  638   ..