1996 TOYOTA LAND CRUISER Workshop Manual

EM1Q7−01
EM−40
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ENGINE MECHANICAL CYLINDER HEAD
1996 LAND CRUISER (RM451U)
INSPECTION
1. CLE AN TO P SURFACE S OF PIS TO NS AND CY L- INDER BLOCK
(a) Turn the crankshaft, and bring each piston to top dead center (TDC). Using a gasket scraper, remove all the car-
bon from the piston top surface.
(b) Using a gasket scraper, remove all the gasket material from the cylinder block surface.
(c) Using compressed air, blow carbon and oil from the bolt holes.
CAUTION:
Protect your eyes when using high −compressed air.
2. CLEAN CYLINDER HEAD
(a) Using a gasket scraper, remove all the gasket material from the cylinder block contact surface.
NOTICE:
Be careful not to scratch the cylinder block contact sur-
face.
(b) Using a wire brush, remove all the carbon from the com- bustion chambers.
NOTICE:
Be careful not to scratch the cylinder block contact sur-
face.
(c) Using a valve guide bushing brush and solvent, clean all the guide bushings.
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EM0580
−
ENGINE MECHANICAL CYLINDER HEAD
EM−41
1996 LAND CRUISER (RM451U)
(d) Using a soft brush and solvent, thoroughly clean the cylin-
der head.
3. INSPECT CYLINDER HEAD
(a) Inspect for flatness. Using a precision straight edge and thickness gauge,
measure the surfaces contacting the cylinder block and
the manifolds for warpage.
Maximum warpage:
Cylinder block side0.15 mm (0.0059 in)
Manifold side0.10 mm (0.0039 in)
If warpage is greater than maximum, replace the cylinder head.
(b) Inspect for cracks.Using a dye penetrant, check the combustion chambers,
intake ports, exhaust ports and cylinder block surface for
cracks.
If cracked, replace the cylinder head.
4. CLEAN VALVES
(a) Using a gasket scraper, chip off any carbon from the valve head.
(b) Using a wire brush, thoroughly clean the valve.
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Z00054
44.5°
EM0181
Margin Thickness
EM−42
−
ENGINE MECHANICAL CYLINDER HEAD
1996 LAND CRUISER (RM451U)
5. INSPECT VALVE STEMS AND GUIDE BUSHINGS
(a) Using a cali per gauge, measure the inside diameter of the
guide bushing.
Bushing inside diameter:
7.010 − 7.030 mm (0.2760 − 0.2768 in.)
(b) Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter:
Intake6.970 − 6.985 mm (0.2744 − 0.2750 in.)
Exhaust6.965 − 6.980 mm (0.2742 − 0.2748 in.)
(c) Subtract the valve stem diameter measurement from the
guide bushing inside diameter measurement.
Standard oil clearance:
Intake0.025 − 0.060 mm (0.0010 − 0.0024 in.)
Exhaust0.030 − 0.065 mm (0.0012 − 0.0026 in.)
Maximum oil clearance:
Intake0.08 mm (0.0031 in.)
Exhaust0.10 mm (0.0039 in.)
If the clearance is greater than maximum, replace the valve and
guide bushing (See page EM−49).
6. INSPECT AND GRIND VALVES
(a) Grind the valve enough to remove pits and carbon.
(b) Check that the valve is ground to the correct valve face angle.
Valve face angle: 44.5°
(c) Check the valve head margin thickness. Margin thickness:
Standard1.2 mm (0.047 in.)
Minimum1.0 mm (0.039 in.)
If the margin thickness is less than minimum, replace the valve.
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P03849
Overall Length
EM0255
P04415
−
ENGINE MECHANICAL CYLINDER HEAD
EM−43
1996 LAND CRUISER (RM451U)
(d) Check the valve overall length.
Standard overall length:
Intake98.4 mm (3.874 in.)
Exhaust97.4 mm (3.854 in.)
Minimum overall length:
Intake97.9 mm (3.854 in.)
Exhaust97.4 mm (3.835 in.)
If the overall length is less than minimum, replace the valve.
(e) Check the surface of the valve stem tip for wear.
If the valve stem tip is worn, resurface the tip with a grinder or
replace the valve.
NOTICE:
Do not grind off more than minimum.
7. INSPECT AND CLEAN VALVE SEATS
(a) Using a 45° carbide cutter, resurface the valve seats.
Remove only enough metal to clean the seats.
(b) Check the valve seating position. Apply a light coat of prussian blue (or white lead) to the
valve face. Lightly press the valve against the seat. Do not
rotate valve.
(c) Check the valve face and seat for the following:
If blue appears 360 ° around the face, the valve is
concentric. If not, replace the valve.
If blue appears 360 ° around the valve seat, the
guide and face are concentric. If not, resurface the
seat.
Check that the seat contact is in the middle of the
valve face with these width:
Intake1.2 − 1.6 mm (0.047 − 0.063 in.)
Exhaust1.0 − 1.4 mm (0.039 − 0.055 in.)
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EM0988
Deviation
EM0801
EM−44
−
ENGINE MECHANICAL CYLINDER HEAD
1996 LAND CRUISER (RM451U)
If not, correct the valve seats as follows: (1) Intake:If the seating is too high on the valve face, use 30 °
and 45 ° cutters to correct the seat.
(2) If the seating is too low on the valve face, use 75° and 45 ° cutters to correct the seat.
(d) Hand−lap the valve and valve seat with an abrasive com- pound.
(e) After hand−lapping, clean the valve and valve seat.
8. INSPECT VALVE SPRINGS
(a) Using a steel square, measure the deviation of the valve spring.
Maximum deviation: 2.0 mm (0.079 in.)
If the deviation is greater than maximum, replace the valve
spring.
(b) Using vernier calipers, measure the free length of the valve spring.
Free length: 43.94 − 45.06 mm (1.7299 − 1.7740 in.)
If the free length is not as specified, replace the valve spring.
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EM0281
P03976
P03977
−
ENGINE MECHANICAL CYLINDER HEAD
EM−45
1996 LAND CRUISER (RM451U)
(c) Using a spring tester, measure the tension of the valve
spring at the specified installed length.
Installed tension:
214 − 238 N (21.8 − 24.2 kgf, 48.1 − 53.4 lbf)
at 36.5 mm (1.437 in.)
If the installed tension is not as specified, replace the valve
spring.
9. INSPECT CAMSHAFTS
(a) Inspect for runout. (1) Place the camshaft on V−blocks.
(2) Using a dial indicator, measure the circle runout atthe center journal.
Maximum circle runout: 0.06 mm (0.0024 in.)
If the circle runout is greater than maximum, replace the cam-
shaft.
(b) Inspect the cam lobes. Using a micrometer, measure the cam lobe height.
Standard cam lobe height:
50.61 − 50.71 mm (1.9925 − 1.9965 in.)
Minimum cam lobe height: 50.51 mm (1.9886 in.)
If the cam lobe height is less than minimum, replace the cam-
shaft.
(c) Inspect the journals. Using a micrometer, measure the journal diameter.
Journal diameter:
26.959 − 26.975 mm (1.0614 − 1.0620 in.)
If the journal diameter is not as specified, check the oil clear-
ance.
(d) Inspect the camshaft bearings. Check that bearings for flaking and scoring.
If the bearings are damaged, replace the bearing caps and cyl-
inder head as a set.
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EM3322
EM−46
−
ENGINE MECHANICAL CYLINDER HEAD
1996 LAND CRUISER (RM451U)
(e) Inspect the gear spring
Using vernier calipers, measure the free distance be-
tween the spring ends.
Free distance: 18.2 − 18.8 mm (0.717 − 0.740 in.)
If the free distance is not as specified, replace the gear spring.
(f) Inspect the journal oil clearance. (1) Clean the bearing caps and camshaft journals.
(2) Place the camshafts on the cylinder head.
(3) Lay a strip of Plastigage across each of the cam-
shaft journals.
(4) Install the bearing caps (See page EM−54).
NOTICE:
Do not turn the camshaft. (5) Remove the bearing caps.
(6) Measure the Plastigage at its widest point.
Standard oil clearance:
0.025 − 0.062 mm (0.0010 − 0.0024 in.)
Maximum oil clearance: 0.10 mm (0.0039 in.)
If the oil clearance is greater than maximum, replace the cam-
shaft. If necessary, replace the bearing caps and cylinder head
as a set. (7) Completely remove the Plastigage.
(g) Inspect the thrust clearance. (1) Install the camshaft (See page EM−54 ).
(2) Using a dial indicator, measure the thrust clearance
while moving the camshaft back and forth.
Standard thrust clearance:
0.030 − 0.080 mm (0.0012 − 0.0031 in.)
Maximum thrust clearance: 0.10 mm (0.0039 in.)
If the thrust clearance is greater than maximum, replace the
camshaft. If necessary, replace the bearing caps and cylinder
head as a set.
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EM2196
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ENGINE MECHANICAL CYLINDER HEAD
EM−47
1996 LAND CRUISER (RM451U)
(h) Inspect the gear backlash.
(1) Install the camshafts without installing the exhaustcam sub−gear (See page EM−54).
(2) Using a dial indicator, measure the backlash.
Standard backlash:
0.020 − 0.200 mm (0.0008 − 0.0079 in.)
Maximum backlash: 0.30 mm (0.0188 in.)
If the backlash is greater than maximum, replace the cam-
shafts.
10. INSPECT VALVE LIFTER OIL CLEARANCE
(a) Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Lifter bore diameter:
34.000 − 34.021 mm (1.3386 − 1.3394 in.)
(b) Using a micrometer, measure the lifter diameter. Lifter diameter:
33.966 − 33.976 mm (1.3372 − 1.3376 in.)
(c) Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance:
0.024 − 0.055 mm (0.0009 − 0.0022 in.)
Maximum oil clearance: 0.07 mm (0.0028 in.)
If the oil clearance is greater than maximum, replace the lifter.
If necessary, replace the cylinder head.
11. INSPECT AIR INTAKE CHAMBER
Using a precision straight edge and thickness gauge, measure
the surface contacting the intake manifold for warpage. Maximum warpage: 0.30 mm (0.0118 in.)
If warpage is greater than maximum, replace the air intake
chamber.
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