Infiniti I35 (A33). Manual — part 491

SEM861E

Inspection

NHEM0046

CYLINDER HEAD DISTORTION

NHEM0046S01

Clean surface of cylinder head.
Use a reliable straightedge and feeler gauge to check the flatness
of cylinder head surface.
Check along six positions shown in the figure.

Head surface flatness: Limit 0.1 mm (0.004 in)

If beyond the specified limit, resurface or replace it.
The limit for cylinder head resurfacing is determined by the
cylinder block resurfacing.

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)

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

Nominal cylinder head height:

126.3 - 126.5 mm (4.972 - 4.980 in)

PBIC0929E

CAMSHAFT VISUAL CHECK

NHEM0046S02

Check camshaft for scratches, seizure and wear.

CAMSHAFT RUNOUT

NHEM0046S03

1.

Put V block on precise flat bed, and support No. 2 and No. 4
journal of camshaft.

2.

Set dial gauge vertically to No. 3 journal.

3.

Turn camshaft to one direction with hands, and measure cam-
shaft runout on dial gauge. (Total indicator reading)

Runout:

Limit (Total indicator reading) 0.05 mm (0.0020 in)

4.

If it exceeds the limit, replace camshaft.

SEM549A

CAMSHAFT CAM HEIGHT

NHEM0046S04

1.

Measure camshaft cam height.

Standard cam height:

Intake and exhaust

44.865 - 45.055 mm (1.7763 - 1.7738 in)

Cam wear limit:

0.2 mm (0.008 in)

2.

If wear is beyond the limit, replace camshaft.

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CYLINDER HEAD

Inspection

EM-55

SEM862E

CAMSHAFT JOURNAL CLEARANCE

NHEM0046S05

1.

Install camshaft bracket and tighten bolts to the specified
torque.

2.

Measure inner diameter “A” of camshaft bearing.

Standard inner diameter:

No. 1: 26.000 - 26.021 mm (1.0236 - 1.0244 in)
No. 2, 3, 4: 23.500 - 23.521 mm (0.9252 - 0.9260 in)

SEM012A

3.

Measure outer diameter of camshaft journal.

Standard outer diameter:

No. 1: 25.935 - 25.955 mm (1.0211 - 1.0218 in)
No. 2, 3, 4: 23.445 - 23.465 mm (0.9230 - 0.9238 in)

4.

If clearance exceeds the limit, replace camshaft and/or cylin-
der head.

Camshaft journal clearance:

Standard

No. 1: 0.045 - 0.086 mm (0.0018 - 0.0034 in)
No. 2, 3, 4: 0.035 - 0.076 mm (0.0014 - 0.0030 in)

Limit

0.15 mm (0.0059 in)

SEM864E

CAMSHAFT END PLAY

NHEM0046S06

1.

Install camshaft in cylinder head. Then install dial gauge in
thrust direction on front end of camshaft.

2.

Measure end play of dial gauge when camshaft is moved
forward/backward (in direction to axis).

Camshaft end play:

Standard

0.115 - 0.188 mm (0.0045 - 0.0074 in)

Limit

0.24 mm (0.0094 in)

I

When out of the limit, replace with new camshaft and measure
again.

I

When out of the limit again, replace with new cylinder head.

CYLINDER HEAD

Inspection (Cont’d)

EM-56

PBIC0930E

CAMSHAFT SPROCKET RUNOUT

NHEM0046S07

1.

Put V block on precise flat bed, and support No. 2 and No. 4
journal of camshaft.

2.

Install sprocket on camshaft.

3.

Measure camshaft sprocket runout.

Runout (Total indicator reading):

Less than 0.15 mm (0.0059 in)

4.

If it exceeds the limit, replace camshaft sprocket.

SEM178F

VALVE GUIDE CLEARANCE

NHEM0046S08

1.

Measure valve deflection as shown in the figure. (Valve and
valve guide mostly wear in this direction.)

Valve deflection limit (Dial gauge reading):

Intake 0.24 mm (0.0094 in)
Exhaust 0.28 mm (0.0110 in)

SEM938C

2.

If it exceeds the limit, check valve to valve guide clearance.

a.

Measure valve stem diameter and valve guide inner diameter.

b.

Check that clearance is within specification.

Valve to valve guide clearance limit:

Intake 0.08 mm (0.0031 in)
Exhaust 0.1 mm (0.004 in)

c.

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

SEM008A

VALVE GUIDE REPLACEMENT

NHEM0046S09

1.

To remove valve guide, heat cylinder head to 110 to 130°C
(230 to 266°F) by soaking in heated oil.

SEM931C

2.

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

CAUTION:

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

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CYLINDER HEAD

Inspection (Cont’d)

EM-57

SEM932C

3.

Ream cylinder head valve guide hole.

Valve guide hole diameter (for service parts):

10.175 - 10.196 mm (0.4006 - 0.4014 in)

SEM950E

4.

Heat cylinder head to 110 to 130°C (230 to 266°F) and press
service valve guide onto cylinder head.

Projection “L”:

12.6 - 12.8 mm (0.496 - 0.504 in)

CAUTION:

Cylinder head contains heat. When working, wear protective
equipment to avoid getting burned.
5.

Ream valve guide.

Finished size:

6.000 - 6.018 mm (0.2362 - 0.2369 in)

SEM934C

VALVE SEATS

NHEM0046S10

Check valve seats for any evidence of pitting at valve contact
surface, and reseat or replace if it has worn out excessively.

I

Before repairing valve seats, check valve and valve guide
for wear. If they have worn, replace them. Then correct
valve seat.

I

Use both hands to cut uniformly.

SEM795A

REPLACING VALVE SEAT FOR SERVICE PARTS

NHEM0046S11

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.

2.

Ream cylinder head recess for service valve seat.

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)

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

SEM892B

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.

CAUTION:

Cylinder head contains heat. When working, wear protective
equipment to avoid getting burned.
5.

Cut or grind valve seat using suitable tool to the specified
dimensions as shown in SDS (EM-91).

6.

After cutting, lap valve seat with abrasive compound.

7.

Check valve seating condition.

Seat face angle “

α

”: 45°15

′

- 45°45

′

CYLINDER HEAD

Inspection (Cont’d)

EM-58