Page 1945 of 3371

EM-62Revision: August 2007
CYLINDER HEAD
2004 QX56
Disassembly and AssemblyEBS00ILU
* Refer to GI-45, "Recommended Chemical Products and Sealants" .
DISASSEMBLY
1. Remove spark plug. Refer to EM-27, "REMOVAL" .
2. Remove valve lifter.
Identify installation positions, and store them without mixing them up.
3. Remove valve collet using Tool.
CAUTION:
When working, take care not to damage valve lifter holes.
4. Remove valve spring retainer, valve spring and valve spring
seat.
5. Inspect valve guide clearance. Refer to EM-66, "
Valve Guide
Clearance" .
6. Push valve stem to combustion chamber side, and remove valve.
Identify installation positions, and store them without mixing them up.
1. Spark plug 2. Valve lifter 3. Valve collet
4. Valve spring retainer 5. Valve spring 6. Valve spring seat
7. Valve oil seal 8. Valve guide 9. Valve seat
10. Valve (INT) 11. Valve (EXH) 12. Cylinder head (left bank)
13. Spark plug tube 14. Cylinder head (right bank)
WBIA0470E
Tool number : KV10116200 (J-26336-B)
: KV10115900 (J-26336-20)
: KV10109220 ( — )
WBIA0578E
Page 1946 of 3371

CYLINDER HEAD
EM-63
C
D
E
F
G
H
I
J
K
L
MA
EM
Revision: August 20072004 QX56
7. Remove valve oil seal using Tool.
8. Replace valve seat if necessary. Refer to EM-68, "
VALVE SEAT REPLACEMENT" .
9. Replace valve guide if necessary. Refer to EM-68, "
VALVE SEAT REPLACEMENT" .
10. Remove spark plug tube, as necessary.
Remove spark plug tube out of cylinder head using suitable tool.
CAUTION:
Take care not to damage cylinder head.
Once removed, spark plug tube will be deformed and cannot be reused. Do not remove it unless
absolutely necessary.
ASSEMBLY
1. Install the valve guide if necessary. Refer to EM-66, "VALVE GUIDE REPLACEMENT" .
2. Install the valve seat if necessary. Refer to EM-68, "
VALVE SEAT REPLACEMENT" .
3. Install valve oil seal using Tool.
Apply new engine oil on new valve oil seal joint and seal lip.
Install valve oil seal to specified height "H".
4. Install valves in their original position.
5. Install valve spring seats.
6. Install valve springs.
Install narrow pitch end (Paint mark side) to cylinder head
side.
7. Install valve spring retainers.Tool number : KV10107902 (J-38959)
WBIA0478E
Tool number : KV10115600 (J-38958)
Height "H" (Without valve spring seat installed)
Intake and exhaust : 14.3 - 14.9 mm (0.563 - 0.587 in)
WBIA0490E
SEM 08 5D
Page 1947 of 3371

EM-64Revision: August 2007
CYLINDER HEAD
2004 QX56
8. Install valve collet using Tool.
CAUTION:
When working, take care not to damage valve lifter holes.
9. Install valve lifters.
Install removed parts in there original locations.
If installing new lifters, select the correct size lifter for proper
valve clearance. Refer to EM-52, "
Valve Clearance" .
10. Install spark plug tube if necessary, following the procedure below.
a. Remove old liquid gasket adhering to cylinder-head spark plug tube hole.
b. Apply liquid gasket to area within approximately 12 mm (0.47 in) from edge of spark plug tube press-fit
side.
Use Genuine RTV Silicone Sealant or equivalent. Refer to GI-45, "
Recommended Chemical Prod-
ucts and Sealants" .
c. Press-fit spark plug tube to specified height “H” using suitable
tool.
CAUTION:
When press-fitting, take care not to deform spark plug
tube.
After press-fitting, wipe off liquid gasket protruding onto
cylinder-head upper face.
11. Install spark plugs.
Inspection After DisassemblyEBS00ILV
CYLINDER HEAD DISTORTION
1. Remove any oil, scale, gasket, sealant and carbon deposits from the cylinder head surface.
CAUTION:
Do not allow any debris to enter the oil or coolant passages.
2. Measure the bottom surface of cylinder head for distortion in six
directions as shown.
If measurement exceeds the limit, replace cylinder head.Tool number : KV10116200 (J-26336-B)
: KV10115900 (J-26336-20)
: KV10109220 ( — )
Standard press-fit height “H” :38.4 - 39.4 mm
(1.512 - 1.551 in)
WBIA0578E
KBIA1248E
Standard : 0.03 mm (0.0012 in)
Limit : 0.1mm (0.004 in)
PBIC0075E
Page 1948 of 3371
CYLINDER HEAD
EM-65
C
D
E
F
G
H
I
J
K
L
MA
EM
Revision: August 20072004 QX56
VALVE DIMENSIONS
Check dimensions of each valve. Refer to EM-65, "VA LV E
DIMENSIONS" .
If dimensions are out of the standard, replace valve.
SEM 18 8A
Page 1949 of 3371

EM-66Revision: August 2007
CYLINDER HEAD
2004 QX56
VALVE GUIDE CLEARANCE
Valve Stem Diameter
Measure diameter of valve stem using suitable tool.
Valve Guide Inside Diameter
Measure inside diameter of valve guide using suitable tool.
Valve Guide Clearance
(Valve guide clearance) = (Valve guide inside diameter) – (Valve stem diameter).
If the calculated value exceeds the limit, replace valve and/or valve guide. When the valve guide must be
replaced, refer to EM-66, "
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. Standard
Intake : 5.965 - 5.980 mm (0.2348 - 0.2354 in)
Exhaust : 5.955 - 5.970 mm (0.2344 - 0.2350 in)
SEM 93 8C
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 (0.0031 in)
Exhaust : 0.09 mm (0.0035 in)
SEM 00 8A
Page 1950 of 3371
CYLINDER HEAD
EM-67
C
D
E
F
G
H
I
J
K
L
MA
EM
Revision: August 20072004 QX56
2. Remove the valve guide using suitable tool.
CAUTION:
Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.
3. Ream cylinder head valve guide hole using suitable tool.
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.
CAUTION:
Cylinder head contains heat. When working, wear protec-
tive equipment to avoid getting burned.
6. Ream cylinder head valve guide hole using suitable tool.
SEM 93 1C
Valve guide hole diameter:
Standard
Intake and exhaust : 9.975 - 9.996 mm (0.3927 -
0.3935 in)
Oversize (service)
Intake and exhaust : 10.175 - 10.196 mm
(0.4006 - 0.4014 in)
SEM 93 2C
SEM 00 8A
KBIA2530E
Valve guide hole diameter:
Intake and exhaust : 6.000 - 6.018 mm
(0.2362 - 0.2369 in)
SEM 93 2C
Page 1951 of 3371

EM-68Revision: August 2007
CYLINDER HEAD
2004 QX56
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.
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.
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 valve seat 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.
CAUTION:
Avoid directly touching cold valve seats.
Cylinder head contains heat. When working, wear protective equipment to avoid getting burned.
5. Finish seat to the specified dimensions using suitable tool. Refer
to EM-103, "
Valve Seat" .
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 stage valve seat.
SBIA0322E
Oversize [0.5 mm (0.020 in)] (Service):
Intake : 38.500 - 38.516 mm (1.5157 - 1.5164 in)
Exhaust : 32.700 - 32.716 mm (1.2874 - 1.2880 in)
SEM 79 5A
SEM 00 8A
SEM 93 4C
Page 1952 of 3371

CYLINDER HEAD
EM-69
C
D
E
F
G
H
I
J
K
L
MA
EM
Revision: August 20072004 QX56
6. Grind to obtain the dimensions indicated as shown.
Using compound, grind to adjust valve fitting.
7. Check again for normal contact. Refer to EM-68, "
VALVE SEAT CONTACT" .
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.
If it is not within specifications, replace valve spring.
VALVE SPRING DIMENSIONS AND VALVE SPRING PRESSURE LOAD
Check valve spring pressure at specified spring height.
If measurement is not within specifications, replace the valve spring.
KBIA2531E
KBIA2544E
Limit : Less than 2.2 mm (0.087 in)
PBIC0080E
Standard:
Intake and exhaust
Free height: 50.58 mm (1.9913 in)
Installation height: 37.0 mm (1.457 in)
Installation load: 165.8 - 187.0 N (16.9 -
19.1 kg, 37- 42 lb)
Height during valve open: 28.2 mm (1.110 in)
Load with valve open: 314.8 - 355.0 N (32.1 -
36.2 kg, 71 - 80 lb)
SEM 113