Nissan Silvia. Instruction — part 233
SEM929C
CAMSHAFT SPROCKET RUNOUT
NMEM0019S07
1.
Install sprocket on camshaft.
2.
Measure camshaft sprocket runout.
Runout (Total indicator reading):
Limit 0.25 mm (0.0098 in)
3.
If it exceeds the limit, replace camshaft sprocket.
SEM003D
VALVE GUIDE CLEARANCE
NMEM0019S08
1.
Measure valve deflection as shown in illustration. (Valve and
valve guide mostly wear in this direction.)
Valve deflection limit (Dial gauge reading):
Intake & Exhaust
0.2 mm (0.008 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.
Calculate valve to valve guide clearance.
Valve to valve guide clearance = valve guide inner
diameter − valve stem diameter:
Standard
Intake 0.020 - 0.053 mm (0.0008 - 0.0021 in)
Exhaust 0.040 - 0.073 mm (0.0016 - 0.0029 in)
Limit
Intake 0.08 mm (0.0031 in)
Exhaust 0.1 mm (0.004 in)
c.
If it exceeds the limit, replace valve and remeasure clearance.
I
If clearance still exceeds the limit after replacing valve, replace
valve guide.
SEM008A
VALVE GUIDE REPLACEMENT
NMEM0019S09
1.
To remove valve guide, heat cylinder head to 110 to 130°C
(230 to 266°F).
GI
MA
LC
EC
FE
CL
MT
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
CYLINDER HEAD
Inspection (Cont’d)
EM-45
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.
SEM932C
3.
Ream cylinder head valve guide hole.
Valve guide hole diameter
(for service parts):
Intake
10.175 - 10.196 mm (0.4006 - 0.4014 in)
Exhaust
11.175 - 11.196 mm (0.4400 - 0.4408 in)
SEM083D
4.
Heat cylinder head to 110 to 130°C (230 to 266°F) and press
service valve guide into cylinder head.
Projection “L”:
14.0 - 14.2 mm (0.551 - 0.559 in)
SEM932C
5.
Ream valve guide.
Finished size:
Intake
6.000 - 6.018 mm (0.2362 - 0.2369 in)
Exhaust
7.000 - 7.018 mm (0.2756 - 0.2763 in)
SEM934C
VALVE SEATS
NMEM0019S10
Check valve seats for pitting at contact surface. Resurface or
replace if excessively worn.
I
Before repairing valve seats, check valve and valve guide
for wear. If they are worn, replace them. Then correct valve
seat.
I
Use both hands to cut uniformly.
CYLINDER HEAD
Inspection (Cont’d)
EM-46
SEM795A
REPLACING VALVE SEAT FOR SERVICE PARTS
NMEM0019S11
1.
Bore out old seat until it collapses. Set machine depth stop so
that boring cannot contact bottom face of seat recess in cylin-
der head.
2.
Ream cylinder head recess.
Reaming bore for service valve seat
Oversize [0.5 mm (0.020 in)]:
Intake 35.500 - 35.516 mm (1.3976 - 1.3983 in)
Exhaust 31.500 - 31.516 mm (1.2402 - 1.2408 in)
Use the valve guide center for reaming to ensure valve seat
will have the correct fit.
SEM008A
3.
Heat cylinder head to 110 to 130°C (230 to 266°F).
4.
Press fit valve seat until it seats on the bottom.
SEM892B
5.
Cut or grind valve seat to the specified dimensions using a
suitable tool. Refer to SDS, EM-87.
6.
After cutting, lap valve seat with abrasive compound.
7.
Check valve seating condition.
Seat face angle “
α
”:
44°53
′
- 45°07
′
Contacting width “W”:
Intake
1.4 - 1.7 mm (0.055 - 0.067 in)
Exhaust
1.7 - 2.0 mm (0.067 - 0.079 in)
GI
MA
LC
EC
FE
CL
MT
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
CYLINDER HEAD
Inspection (Cont’d)
EM-47
AEM343
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 the specified valve, repeat step 5
above to adjust it.
If it is longer, replace the valve seat with a new one.
Valve seat resurface limit:
42.74 - 43.26 mm (1.6827 - 1.7031 in)
SEM188A
VALVE DIMENSIONS
NMEM0019S12
Check dimensions of each valve. Refer to SDS, EM-84.
When valve head has been worn down to 0.5 mm (0.020 in) in
margin thickness, replace valve.
Grinding allowance for valve stem tip is 0.2 mm (0.008 in) or
less.
SEM288A
VALVE SPRING
NMEM0019S13
Squareness
NMEM0019S1301
1.
Measure dimension “S”.
Out-of-square “S”:
Less than 2.2 mm (0.087 in)
2.
If it exceeds the limit, replace spring.
EM113
Pressure
NMEM0019S1302
Check valve spring pressure at specified spring height.
Pressure:
Standard
578.0 - 641.6 N (59.0 - 65.4 kg, 129.9 - 144.2 lb) at
30.0 mm (1.181 in)
Limit
549.2 N (56.0 kg, 123.5 lb) at 30.0 mm (1.181 in)
If it exceeds the limit, replace spring.
SEM935C
HYDRAULIC LASH ADJUSTER
NMEM0019S14
1.
Check contact and sliding surfaces for wear or score.
CYLINDER HEAD
Inspection (Cont’d)
EM-48
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