Nissan Maxima. Manual - part 552

EM-96

< REMOVAL AND INSTALLATION >

CYLINDER HEAD

Check along six positions as shown.

CAUTION:

If it exceeds the limit, replace the cylinder head.

• The limit for cylinder head resurfacing is determined by the

cylinder block resurfacing.

• After resurfacing cylinder head, check that camshaft rotates freely by hand. If resistance is felt, cylinder head

must be replaced.

VALVE GUIDE CLEARANCE

1. Measure valve deflection as shown. (Valve and valve guide

mostly wear in this direction.)

2. If it exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.

Refer to 

EM-132, "Cylinder Head"

.

b. Check that clearance is within specification.

(Valve guide clearance) = (Valve guide inner diameter) - (Valve

stem diameter)

c.

If it exceeds the limit, replace valve or valve guide.

VALVE GUIDE REPLACEMENT

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

Head surface distortion
Limit

: 0.1 mm (0.004 in)

Standard

: Less than 0.03 mm 
(0.0012 in)

Resurfacing Limit
Amount of cylinder head resurfacing is “A”.
Amount of cylinder block resurfacing is “B”.
The maximum limit 

: A + B = 0.2 mm (0.008 in)

Nominal cylinder head height

: 126.3 - 126.5 mm (4.972 - 4.980 in)

SEM861E

Valve deflection limit (dial gauge reading)
Intake

: 0.24 mm (0.0094 in)

Exhaust

: 0.28 mm (0.0110 in)

SEM178F

Valve to valve guide clearance standard
Intake

: 0.020 - 0.053 mm (0.0008 - 0.0021 in)

Exhaust

: 0.040 - 0.073 mm (0.0016 - 0.0029 in)

Valve to valve guide clearance limit
Intake

: 0.08 mm (0.0031 in)

Exhaust

: 0.1 mm (0.004 in)

SEM938C

CYLINDER HEAD

EM-97

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1. To remove valve guide, heat cylinder head to 110

° to 130°C

(230

° to 266°F) by soaking in heated oil.

WARNING:

Cylinder head contains heat. When working, wear protec-

tive equipment to avoid getting burned.

2. Drive out the valve guide with a press [under a 20 kN (2.2 US

ton) pressure] or hammer and suitable tool.

3. Ream cylinder head valve guide hole.

4. Heat cylinder head to 110

° to 130°C (230° to 266°F) by soaking

in heated oil and press new valve guide from camshaft side into

the cylinder head to the dimensions as shown.

WARNING:

Cylinder head contains heat. When working, wear protec-

tive equipment to avoid getting burned.

SEM008A

SEM931C

Valve guide hole diameter 
(for service parts), intake 
and exhaust

: 10.175 - 10.196 mm 
(0.4006 - 0.4014 in)

SEM932C

Projection "L"

: 12.6 - 12.8 mm (0.496 - 0.504 in)

SEM950E

EM-98

< REMOVAL AND INSTALLATION >

CYLINDER HEAD

5. Using a valve guide reamer, apply a reamer finish to the valve

guide.

VALVE SEAT CONTACT

• After confirming that the dimensions of valve guides and valves are

within specifications, perform this procedure. 

• Apply prussian blue onto contacting surface of valve seat to check

the condition of the valve contact on the surface.

• Check if the contact area band is continuous all around the circum-

ference.

• If not, grind to adjust valve fitting and check again. If the contacting

surface still has N.G conditions even after the re-check, replace

valve seat.

VALVE SEAT REPLACEMENT

1. Bore out old valve seat until it collapses. Boring should not con-

tinue beyond the bottom face of the valve seat recess in cylinder

head. Set the machine depth stop to ensure this.

2. Ream cylinder head recess for service valve seat.

Be sure to ream in circles concentric to the valve guide cen-

ter.

This will enable valve seat to fit correctly.

3. Heat cylinder head to 110

° to 130°C (230° to 266°F) by soaking in heated oil.

4. Press fit valve seat until it seats on the bottom.
5. Cut or grind valve seat using suitable tool to the specified dimensions. Refer to 

EM-132, "Cylinder Head"

.

6. After cutting, lap valve seat with abrasive compound.
7. Check valve seating condition.

Intake and exhaust 
finished size

: 6.000 - 6.018 mm
(0.2362 - 0.2369 in)

SEM932C

SBIA0322E

Oversize

: 0.5 mm (0.020 in)

Intake

: 38.500 - 38.516 mm 
(1.5157 - 1.5164 in)

Exhaust

: 32.100 - 32.116 mm 
(1.2638 - 1.2644 in)

Seat face angle “

α”

:  45

° 15' - 45° 45' de-

grees/minutes

Contacting width “W” for intake

: 1.18 - 1.22 mm 
(0.0465 - 0.0480 in)

Contacting width “W” for exhaust

: 1.38 - 1.42 mm 
(0.0543 - 0.0559 in)

SEM795A

SEM892B

CYLINDER HEAD

EM-99

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8. Use a depth gauge to measure the distance between the mount-

ing surface of the cylinder head spring seat and the valve stem

end. If the distance is shorter than specified, repeat step 5 to

adjust it. If it is longer, replace the valve seat with a new one.

VALVE SPRING SQUARENESS

Set try square along the side of valve spring and rotate the spring.

Measure the maximum clearance between the top face of spring and

try square.

VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD

Check valve spring pressure at specified spring height.

If it is not within specifications, replace the spring.

Valve seat resurface limit “L” in-
take

: 41.16 - 41.76 mm 
(1.6205 - 1.6441 in)

Valve seat resurface limit “L” ex-
haust

: 41.09 - 41.69 mm 
(1.6177 - 1.6413 in)

SEM621F

Out-of-square limit

: Less than 2.0 mm (0.079 in)

PBIC0080E

Standard

: 166 - 188 N (16.9 - 19.2 kg, 37.3 - 42.3 lb) at 
height 37.0 mm (1.457 in)

Limit

: 373 - 421 N (38.0 - 42.9 kg, 84 - 95 lb) at 
height 27.2 mm (1.071 in)

SEM113