Infiniti G35 (V35). Manual - part 493

CYLINDER HEAD

EM-127

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VALVE GUIDE CLEARANCE
Valve Stem Diameter

Measure the diameter of valve stem with micrometer.

Valve Guide Inner Diameter

Measure the inner diameter of valve guide with bore gauge.

Valve Guide Clearance

(Valve guide clearance) = (Valve guide inner diameter) – (Valve stem diameter)

●

If it exceeds the limit, replace valve and/or valve guide. When valve guide must be replaced. Refer to 

EM-

127, "VALVE GUIDE REPLACEMENT"

 .

VALVE GUIDE REPLACEMENT

When valve guide is removed, replace with oversized [0.2 mm (0.008 in)] valve guide.

1.

To remove valve guide, heat cylinder head to 110 to 130

°

C (230

to 266

°

F) by soaking in heated oil.

2.

Drive out valve guide with a press [under a 20 kN (2 ton, 2.2 US
ton, 2.0 lmp ton) pressure] or hammer and suitable tool.

WARNING:

Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.

Standard

Intake

: 5.965 - 5.980 mm (0.2348 - 0.2354 in)

Exhaust

: 5.955 - 5.970 mm (0.2344 - 0.2350 in)

SEM938C

Standard

Intake and Exhaust

: 6.000 - 6.018 mm (0.2362 - 0.2369 in)

Valve guide clearance:

Standard

Intake

: 0.020 - 0.053 mm (0.0008 - 0.0021 in)

Exhaust

: 0.030 - 0.063 mm (0.0012 - 0.0025 in)

Limit

Intake

: 0.08 mm (0.003 in)

Exhaust

: 0.09 mm (0.004 in)

SEM008A

SEM931C

EM-128

CYLINDER HEAD

3.

Using valve guide reamer (commercial service tool), ream cylin-
der head valve guide hole.

4.

Heat cylinder head to 110 to 130

°

C (230 to 266

°

F) by soaking in

heated oil.

5.

Press valve guide from camshaft side to dimensions as in the
figure.

WARNING:

Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.

6.

Using valve guide reamer (commercial service tool), apply
reamer finish to valve guide.

Valve guide hole diameter (for service parts):

Intake and exhaust

: 10.175 - 10.196 mm (0.4006 - 0.4014 in)

SEM932C

SEM008A

Projection “L”

Intake and exhaust

: 12.6 - 12.8 mm (0.496 - 0.504 in)

SEM950E

Standard:

Intake and exhaust

: 6.000 - 6.018 mm (0.2362 - 0.2369 in)

SEM932C

CYLINDER HEAD

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VALVE SEAT CONTACT

●

After confirming that the dimensions of valve guides and valves
are within specifications, perform this procedure.

●

Apply prussian blue (or white lead) onto contacting surface of
valve seat to check the condition of the valve contact on the sur-
face.

●

Check if the contact area band is continuous all around the cir-
cumference.

●

If not, grind to adjust valve fitting and check again. If the contact-
ing surface still has NG conditions even after the re-check,
replace valve seat. Refer to 

EM-129, "VALVE SEAT REPLACE-

MENT"

 .

VALVE SEAT REPLACEMENT

When valve seat is removed, replace with oversized (0.5 mm, 0.020 in) valve seat.
1.

Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess
in cylinder head. Set the machine depth stop to ensure this. Refer to 

EM-173, "Valve Seat"

 .

CAUTION:

prevent to scratch cylinder head by excessive boring.

2.

Ream cylinder head recess diameter for service valve seat.

●

Be sure to ream in circles concentric to valve guide center.
This will enable valve to fit correctly.

3.

Heat cylinder head to 110 to 130

°

C (230 to 266

°

F) by soaking in

heated oil.

4.

Provide valve seats cooled well with dry ice. Force fit valve seat into cylinder head.

WARNING:

Cylinder head contains heat. When working, wear protective equipment to avoid getting burned.

CAUTION:

Avoid directly touching cold valve seats.

SBIA0322E

Oversize [0.5 mm (0.020 in)]

Intake

: 38.500 - 38.516 mm (1.5157 - 1.5164 in)

Exhaust

: 32.700 - 32.716 mm (1.2874 - 1.2880 in)

SEM795A

SEM008A

EM-130

CYLINDER HEAD

5.

Using valve seat cutter set (commercial service tool) or valve
seat grinder, finish seat to the specified dimensions. Refer to

EM-173, "Valve Seat"

 .

CAUTION:

When using valve seat cutter, firmly grip cutter handle with
both hands. Then, press on the contacting surface all
around the circumference to cut in a single drive. Improper
pressure on with cutter or cutting many different times may
result in stage valve seat. 

6.

Using compound, grind to adjust valve fitting. 

7.

Check again for normal contact.

VALVE SPRING SQUARENESS

●

Set try square along the side of valve spring and rotate spring.
Measure the maximum clearance between the top face of spring
and try square.

●

If it exceeds the limit, replace valve spring.

VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD

●

Check valve spring pressure at specified spring height.

Standard:

●

If the installation load or load with valve open is out of the standard, replace valve spring.

SEM934C

Limit:

M/T models

: 2.0 mm (0.079 in)

A/T models

: 2.1 mm (0.083 in)

PBIC0080E

SEM113

Items

M/T models

A/T models

Free height

45.43 mm (1.7886 in)

47.07 mm (1.8531 in)

Installation height

37.00 mm (1.4567 in)

37.00 mm (1.4567 in)

Installation load

166 - 188 N (16.9 - 19.2 kg, 37 - 42 lb)

166 - 188 N (16.9 - 19.2 kg, 37 - 42 lb)

Height during valve open

26.8 mm (1.0551 in)

27.2 mm (1.0709 in)

Load with valve open

434 - 490 N (44.3 - 50.0 kg, 97.6 - 110.2 lb)

373 - 421 N (38.0 - 42.9 kg, 84 - 95 lb)

Identification color

Purple

Blue