1991 LEXUS SC400 engine oil

10. INSPECT CAMSHAFTS AND BEARINGS
A. Inspect camshaft for runout
(a) Place the camshaft on V±blocks.
(b) Using a dial indicator, measure the circle runout at the centerjournal.
Maximum circle runout:
0.08 mm (0.0031 in.)
If the circle runout is greater than maximum, replace the cam-
shaft.
B. Inspect cam lobes Using a micrometer, measure the cam lobe height.
Standard cam lobe height:
Intake41.710 ± 41.810 mm (1.6421 ± 1.6461 in.)
Exhaust 41.910 ± 42.010 mm (1.6500 ± 1.6539 in.)
Minimum cam lobe height: Intake41.56 mm (1.6362 in.)
Exhaust
41.76 mm (1.6441 in.)
If the cam lobe height is less than minimum, replace the cam-
shaft.
C. Inspect camshaft journals Using a micrometer, measure the journal diameter.
Journal diameter:
Exhaust camshaft thrust portion (A)23.959 ± 23.975 mm (0.9433 ± 0.9439 in.)
Others 26.954 ± 26.970 mm (1.0612 ± 1.0618 in.)
If the journal diameter is not as specified, check the oil clear-
ance.
EG±102
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D. Inspect camshaft bearingsCheck that bearings for flaking and scoring.
If the bearings are damaged, replace the bearing caps and
cylinder head a set.
E. Inspect camshaft gear spring Using a vernier caliper measure the free distance between
the spring ends.
Free distance:
18.2 ± 18.8 mm (0.712 ± 0.740 in.)
If the free distance is not as specified, replace the gear
spring.
F. Inspect camshaft journal oil clearance
(a) Clean the bearing caps and camshaft journals.
(b) Place the camshafts on the cylinder head.
(c) Lay a strip of Plasti gage across each of the camshaft
journals.
(d) Install the bearing caps. (See step 7 on pages EG±114 to 120)
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
NOTICE: Do not turn the camshaft.
(e) Remove the bearing caps.
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(f) Measure the Plastigage at its widest point.
Standard oil clearance:Exhaust camshaft thrust portion
0.025 ± 0.061 mm (0.0010 ± 0.0024 in.)
Others 0.030 ± 0.067 mm (0.0012 ± 0.0026 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.
(g) Completely remove the Plastigage.
(h) Remove the camshafts.
G. Inspect camshaft thrust clearance
(a) Install the camshaft. (See step 7 on pages EG±114 to 120)
(b) Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance:
0.040 ± 0.090 mm (0.0016 ± 0.0035 in.)
Maximum thrust clearance: 0.12 mm (0.0047 in.)
If the thrust clearance is greater than maximum, replace the
camshaft. If necessary, replace the bearing caps and cylin-
der head as a set.
(c) Remove the camshafts.
EG±104
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H. Inspect camshaft gear backlash
(a) Install the camshafts without installing the exhaust camsub±gear.
(See step 7 on pages EG±114 to 120)
(b) 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 then maximum, replace the cam-
shafts.
(c) Remove the camshafts.
11. INSPECT VALVE LIFTERS AND LIFTER BORES
(a) Using a caliper gauge, measure the ufter bore diameter of the
clinder head.
Lifter bore diameter:
31.000±31.016 mm (1.2205±1.2211 in.)
(b) Using a micrometer, measure the lifter diameter.
Lifter diameter:30.966 ± 30.976 mm (1.2191 ± 1.2195 in.)
(c) Subtract the lifter diameter measurement from the lifter borediameter measurement.
Standard oil clearance:
0.024 ± 0.050 mm (0.0009 ± 0.0020 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.
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16. IF NECESSARY, REPLACE SPARK PLUG TUBEGASKETS
(a) Bend the ventilation case claw installed on the cylinder head
cover to an angle of 90
or more.
(b) Using SST and a hammer, tap out the gasket. SST 09550±10012 (09552±10010, 09560±10010)
(c) Using SST and a hammer, tap in a new gasket until its surface
is flush with the upper edge of the cylinder head cover.
SST 09550±10012 (09552±10010, 09560±10010)
(d) Apply a light coat of MP grease to the gasket lip.
(e) Return the ventilation case claw to its original position.
CYLINDER HEAD ASSEMBLY
EG1KN±02
(See Components for Removal and Installation) HINT:
wThoroughly clean all parts to be assembled.
w Before installing the parts, apply new engine oil to all
sliding and rotating surfaces.
w Replace all gaskets and oil seals with new ones.
1. INSTALL SPARK PLUG TUBES HINT: When using a new cylinder head, spark plug tubes
must be installed.
(a) Apply adhesive to the end of the spark plug tube.
Adhesive:
Part No. 08833±00070, THREE BOND 1324 or equivalent
(b) Using a wooden block and hammer, tap in a new spark tubeuntil there is 48.7 ± 49.3 mm (1.917 ± 1.941) protruding from
the camshaft bearing cap installation surface of the cylinder
head.
NOTICE: Avoid tapping a new spark plug tube in too far
by measuring the amount of the protrusion while tap-
ping.
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2. INSTALL VALVES
(a) Using SST, push in a new oil seal.SST 09201±41020
(b) Install the following parts: (1) Valve
(2) Spring seat
(3) Valve spring
(4) Spring retainer
(c) Using SST, compress the valve spring and place the 2 keepers around the valve stem.
SST 09202±70010
(d) Using a plastic±faced hammer, lightly tap the valve stem tip to assure proper fit.
3. INSTALL VALVE LIFTERS AND SHIMS
(a) Install the valve lifter and shim.
(b) Check that the valve lifter rotates smoothly by hand.
EG±108
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B. Install cylinder head boltsHINT:
wThe cylinder head bolts are tightened in 2 progressive
steps (steps (c) and (e)).
w If any cylinder head bolt is broken or deformed, replace
it.
(a) Apply a light coat of engine oil on the threads and under the
heads of the cylinder head bolts.
(b) Install the plate washer to the cylinder head bolt.
(c) Install and uniformly tig hten the 10 cylinder head bolts on one
side of the cylinder head in several passes in the sequence
shown, then do the other side as shown.
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
If any one of the cylinder head bolts does not meet the torque
specification, replace the cylinder head bolt.
NOTICE: Do not drop the plate washer for cylinder head bolt
into portion A of the cylinder head. If dropped into portion A,
the plate washer will pass through the cylinder head and cylin-
der block into the oil pan.
(d) Mark the front of the cylinder head bolt head with paint.
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(d) RH Cylinder Head:Install the bearing cap (mark ª11º) in position with the arrow
mark facing rearward.
(e) LH Cylinder Head: Install the bearing cap (mark ª16º) in position with the arrow
mark facing forward.
(f) Install a new seal washer to the bearing cap bolt.
(g) Apply a light coat of engine oil on the threads of the bearing
cap bolt.
(h) Install the 4 bearing cap bolts. Alternately tighten bearing cap bolts.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
HINT: Use silver colored bolts 38 mm (1.50 in.) in length.
6. ASSEMBLE EXHAUST CAMSHAFT
(a) Install the following parts: (1) Camshaft gear spring
(2) Camshaft sub±gear
(3) Wave washer
HINT: Align the pins on the gears with the spring ends.
(b) Using snap ring pliers, install the snap ring.
(c) Mount the hexagon wrench head portion of the camshaft in a vise.
NOTICE: Be careful not to damage the camshaft.
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