Nissan Altima L32. Instruction — part 633
EM-68
< ON-VEHICLE REPAIR >
[QR25DE]
CYLINDER HEAD
9. Install spark plug tube.
a. Remove old liquid gasket from cylinder head side mounting
hole.
b. Apply liquid gasket all around on spark plug tube with a 12 mm
(0.47 in) width from edge of spark plug tube on the press fit side.
• Use Three Bond or equivalent. Refer to
mended Chemical Products and Sealants"
c.
Press fit spark plug tube so that height is to (H) as shown.
CAUTION:
• When press fitting be careful not to deform spark plug tube.
• After press fitting, wipe off any protruding liquid gasket on top surface of cylinder head.
10. Install spark plug using suitable tool.
Inspection After Disassembly
INFOID:0000000004202132
CYLINDER HEAD DISTORTION
1. Wipe off oil and remove water scale deposits, old gasket, old
sealer, and carbon with a scraper.
CAUTION:
Use care not to allow gasket debris to enter passages for oil
or water.
2. At each of several locations on bottom surface of cylinder head,
measure distortion in six directions.
VALVE DIMENSIONS
Check dimensions of each valve. Refer to
.
VALVE GUIDE CLEARANCE
• Measure diameter of valve stem using suitable tool (A) as shown.
• Measure inner diameter of valve guide with a bore gauge as shown.
• Valve guide clearance = (Valve guide inner diameter) - (Valve stem diameter)
Press fit height (H) standard value
: 41.7 mm (1.642 in)
PBIC2713E
Limit
: 0.1 mm (0.004 in)
PBIC0075E
Standard
Intake
: 5.965 - 5.980 mm (0.2348 - 0.2354 in)
Exhaust
: 5.955 - 5.970 mm (0.2344 - 0.2350 in)
AWBIA0068ZZ
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)
CYLINDER HEAD
EM-69
< ON-VEHICLE REPAIR >
[QR25DE]
C
D
E
F
G
H
I
J
K
L
M
A
EM
N
P
O
• If it exceeds the limit, replace valve guide and/or valve. When valve guide must be replaced, follow the
"VALVE GUIDE REPLACEMENT" procedure.
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 (2.2 ton-force)
pressure] or hammer and suitable tool.
3. Ream cylinder head valve guide hole using suitable reamer.
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 shown.
Limit
Intake
: 0.08 mm (0.003 in)
Exhaust
: 0.09 mm (0.004 in)
SEM008A
SEM931C
Intake and exhaust valve guide
hole diameter (Service)
: 10.175 - 10.196 mm
(0.4006 - 0.4014 in)
SEM932C
PBIC0078E
EM-70
< ON-VEHICLE REPAIR >
[QR25DE]
CYLINDER HEAD
6. Apply finish to valve guide using suitable reamer.
VALVE SEAT CONTACT
NOTE:
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 seat sur-
face.
• 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 NG conditions even after the re-check, replace the
valve seat.
VALVE SEAT REPLACEMENT
NOTE:
When valve seat is removed, replace with an 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 the cylinder head. Set the machine depth stop to ensure this.
2. Ream cylinder head recess diameter for service valve seat.
• Be sure to ream in circles concentric to the valve guide center.
This will enable the valve seat to fit correctly.
3. Heat cylinder head to 110
° to 130°C (230° to 266°F) by soaking
in heated oil.
4. Use valve seats cooled well with dry ice. Force fit valve seat into cylinder head.
CAUTION:
Avoid directly touching the cold valve seats.
Intake and exhaust
: 6.000 - 6.018 mm (0.2362 -
0.2369 in)
SEM932C
SBIA0322E
Intake
: 37.000 - 37.016 mm (1.4567 - 1.4573 in)
Exhaust
: 32.000 - 32.016 mm (1.2598 - 1.2605 in)
SEM795A
SEM008A
CYLINDER HEAD
EM-71
< ON-VEHICLE REPAIR >
[QR25DE]
C
D
E
F
G
H
I
J
K
L
M
A
EM
N
P
O
5. Finish the seat to the specified dimensions using suitable tool.
.
CAUTION:
When using valve seat cutter, firmly grip the cutter handle
with both hands. Then, press on the contacting surface all
around the circumference to cut in a single drive. Improper
pressure on the cutter or cutting many different times may
result in a defective 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 the valve spring and rotate the
spring. Measure the maximum clearance between the top face of the
spring and the try square.
VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD
Check valve spring pressure with valve spring seat installed at spec-
ified spring height. Replace if not within specifications.
CAUTION:
Do not remove the valve spring seat.
SEM934C
Limit
: 1.9 mm (0.0748 in)
PBIC0080E
SEM113
STANDARD
INTAKE
EXHAUST
Free height
43.72 - 43.92 mm (1.7213 - 1.7291 in)
45.29 - 45.49 mm (1.7831 - 1.7909 in)
Installation height
35.30 mm (1.390 in)
35.30 mm (1.390 in)
Installation load
151 - 175 N (15.4 - 17.8 kg-f, 34 - 39 lb-f)
151 - 175 N (15.4 - 17.8 kg-f, 34 - 39 lb-f)
Height during valve
open
25.30 mm (0.9961 in)
26.76 mm (1.0535 in)
Load with valve open
351 - 394 N (35.8 - 40.2 kg-f, 79 - 89 lb-f)
318 - 362 N (32.4 - 37.8 kg-f, 72 - 81 lb-f)
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст