timing belt LEXUS SC400 1991 Service Repair Manual

TORQUE SPECIFICATIONS
Part tightenedNVmkgf Vcmft Vlbf
Engine drain plug X Cylinder block1818013
Coolant filler plug X Water inlet housing44450 33
Water pump X Cylinder block18185 13
Water inlet housing X Water pump18185 13
Water inlet X Water inlet housing18185 13
Radiator fan shroud X Radiator4.950 43 in. Vlbf
Radiator X Body12120 9
Cooling fan reservoir tank X Radiator fan shroud4.950 43 in. Vlbf
Cooling fan inlet pipe X Radiator fan shroud4.950 43 in. Vlbf
Cooling fan pressure hose X Hydraulic motor64650 47
Radiator reservoir tank X Upper radiator support4.950 43 in. Vlbf
Radiator reservoir tank X Radiator reservoir tank support4.950 43 in. Vlbf
Hydraulic pump rear housing X End plug (for spool valve)19200 14
Hydraulic pump front housing X Rear housing21210 15
Hydraulic pump pulley X Drive shaft59600 43
Solenoid valve X Hydraulic pump rear housing39400 28
Hydraulic pump suction port union X Rear housing13135 10
 Hydraulic pump X Cylinder block 12 mm head 16 160 12
  14 mm head 20 310 22
\
 \
Cooling fan pressure hose X Hydraulic pump 64 650 47
\
 \
RH No.2 timing belt cover X Cylinder block 16 160 12
\
 \
Drive belt idler pulley X Hydraulic pump 37 380 27
\
 \
A/C compressor X Hydraulic pump 49 500 36
\
 \
A/C compressor X Cylinder block 49 500 36\
 \
A/C compressor stay X Oil filter bracket 29 300 22\
 \
Hydraulic motor cover X Motor housing 28 290 21\
 
\

\
Hydraulic motor X Radiator fan shroud
 

4.9
 

50
 

43 in.
Vlbf
\
 \
Cooling fan X Hydraulic motor 15 150 11
\
 \
Cooling fan oil cooler X Body 18 180 13
\
 \
Water temperature sensor X Radiator 7.4 75 65 in. Vlbf
±
COOLIING SYSTEM Service SpecificationsCO±65
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Coolant which is heated in the water jacket is pumped to the radiator, through which a cooling fan blows
air to cool the coolant as it passes through. Coolant which has been coo\
led is then sent back to the engine by
the water pump, where it cools the engine. The water jacket is a network of channels in the shell of the cylinder bloc\
k and cylinderhead through which
coolant passes. It is designed to provide adequate cooling through the cylinders and combus\
tion chambers
which become heated during engine operation.
RADIATOR The radiator performs the function of cooling the coolant which has pass\
ed through the waterjacket and
become hot, and it is mounted in the front of the vehicle. The radiator consis\
ts of an upper tank and lower tank,
and a core which connects the two tanks. The upper tank contains the inlet \
for coolant from the water jacket
and the filler inlet. It also has a hose attached through which excess cool\
ant or steam can flow. The lower tank
contains the outlet for coolant and drain plug. The core contains many t\
ubes through which coolant flows from
the upper tank to the lower tank as well as cooling fins which radiate heat\
away from the coolant in the tubes.
The air sucked through the radiator by the cooling fan, as well as the wind generated by the ve\
hicle's travel,
passes through the radiator, cooling the coolant. Models with automatic transmission include an aut\
omatic
transmission fluid cooler built into the lower tank of the radiator. A cooling fan is mounted behind radiator to assist
the flow of air through the radiator. When the coolant temperature is low, the fan operates slowly to help the warm
up, and when the coolant temperature becomes high, the fan speed is increas\
ed to provide the air flow required
for cooling.
RADIATOR CAP (on Reservoir Tank)
The radiator cap is a pressure type cap which seals the radiator, resulting in pressurization of the radiator
as the coolant expands. The pressurization prevents the coolant from boi\
ling even when the coolant tempera-
ture exceeds 100 5C (212 5F). A relief valve (pressurization valve) and a vacuum valve (negati\
ve pressure valve)
are built into the radiator cap. The relief valve opens and lets steam esca\
pe through the overflow pipe when
the pressure generated inside the cooling system exceeds the limit (coolant temperature: 110±120 5C
(230±248 5F) pressure; 29.4±98.1 kPa (0.3±1.0 kgf/cm2, 4.3±14.2 psi)). The vacuum v\
alve opens to alleviate
the vacuum which develops in the coolant system after the engine is stopped\
and the coolant temperature
drops.
RESERVOIR TANK The purpose of the reservoir tank is to catch coolant overflows created by \
volumetrix expansion when the
coolant temperature increases. The cap of the reservoir tank is a pressure type\
which prevents deterioration
of the LLC (Long Life Coolant) caused by contact with atmospheric air, increases vaporization performance and
reduces loss of the coolant volume.
WATER PUMP The water pump is mounted on the front of the cylinder block and driven by t\
he reverse side of the timing
belt.
THERMOSTAT The thermostat has a wax type by±pass valve and is mounted in the wat\
er inlet housing. The thermostat
begins to open at the temperature of 80 5C (180 5F). When the coolant temperature is low, the valve closes to
prevent coolant flow to the radiator, thus permitting the engine to warm up rapidly. When the by±pass valve
opens the by±pass circuit, the engine coolant continues to circulate \
inside the engine, quickly and uniformly
warming up to the appropriate temperature. When the coolant temperature is high\
, the valve opens and coolant
flows to the radiator where it is cooled. When the wax inside the thermostat \
is heated, it expands and thus
creates pressure which overpowers the force of the spring which keeps the valve\
closed. When the wax cools,
its contraction causes the force of the spring to take effect once more, closing the valve.
ELECTRONICALLY CONTROLLED HYDRAULIC COOLING FAN (See page CO±22)
±
COOLIING SYSTEM DescriptionCO±3
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WATER PUMP
COMPONENTS FOR REMOVAL AND
INSTALLATION
REMOVAL OF WATER PUMP
1. REMOVE TIMING BELT(See steps 1 to 35 on pages EM±35 to 43)
2. REMOVE RH IGNITION COIL (a) Disconnect the ignition coil connector.
(b) Remove the two bolts and ignition coil.
3. REMOVE WATER INLET AND INLET HOUSING (a) Disconnect the water by±pass hose from the water inlethousing.
CO±8
±
COOLIING SYSTEM Water Pump
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(b) Apply seal packing to the sealing groove of the waterinlet housing as shown in the illustration.
Seal packing: Part No. 08826±00100 or equivalent
w Install a nozzle that has been cut to a 2±3 mm
(0.08±0.12 in.) opening.
HINT: Avoid applying an excessive amount to the surface. w Parts must be assembled within 5 minutes of
application. Otherwise the material must be
removed and reapplied.
w Immediately remove nozzle from the tube and
reinstall cap.
(c) Install a new O±ring to the water inlet housing.
(d) Apply soapy water to the O±ring.
(e) Push the water inlet housing end into water pump hole.
(f) Install the water inlet and inlet housing assembly with the two bolts. alternately tighten the bolts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT: Use bolts 25 mm (0.98 in.) in length.
(g) Connect the water by±pass hose to the water inlet
housing.
3. INSTALL RH IGNITION COIL (a) Install the ignition coil with the two bolts.
(b) Connect the ignition coil connector.
4. INSTALL TIMING BELT (See steps 4 to 43 on pages EM±47 to 57)
±
COOLIING SYSTEM Water PumpCO±11
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10. REMOVE LH ENGINE WIRE COVERRemove the two bolts and engine wire cover.
11. REMOVE VSV FOR EVAP SYSTEM Remove the two bolts, and disconnect the VSV from cylinder
head and timing belt cover.
12. REMOVE RH NO.3 TIMING BELT COVER Remove the three bolts and timing belt cover.
13. REMOVE LH NO.3 TIMING BELT COVER (a) Remove the four mounting bolts.
(b) Disconnect the cord grommet from the timing belt cover,
and remove the timing belt cover.
(c) Remove the cord grommet from the high±tension cord.
14. DISCONNECT RADIATOR HOSE FROM WATER INLET
15. REMOVE DRIVE BELT IDLER PULLEY Remove the pulley bolt, cover plate and idler pulley.
±
COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)CO±29
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15. REMOVE RH NO.2 TIMING BELT COVER(a) Disconnect the cam position sensor connector from theignition coil bracket.
(b) Disconnect the cam position sensor wire from the clamp
on the timing belt cover.
(c) Remove the five mounting bolts.
(d) Disconnect the wire clamp from the timing belt cover,
and remove the timing belt cover and four gasket.
16. REMOVE LH NO.2 TIMING BELT COVER (a) Disconnect the cam position sensor wire from the clamp
on the timing belt cover.
(b) Disconnect the cam position sensor connector.
(c) Remove the three mounting bolts.
(d) Disconnect the connector grommet from the timing belt cover, and remove the timing belt cover and two
gaskets.
17. DISCONNECT PRESSURE AND SUCTION HOSES FROM HYDRAULIC PUMP
18. REMOVE HYDRAULIC PUMP (a) Disconnect the solenoid valve connector.
(b) Remove the two mounting bolts and two nuts.
(c) Disconnect the engine speed sensor wire clamp.
(d) Remove the hydraulic pump.
CO±30
±
COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)
WhereEverybodyKnowsYourName

INSTALLATION OF HYDRAULIC PUMP
(See Components on page CO±26)
1. INSTALL HYDRAULIC PUMP (a) Install the hydraulic pump, solenoid valve connector
clamp and engine speed sensor wire clamp with the two
bolts and two nuts.
Torque:
12 mm head 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
14 mm head 20 N Vm (310 kgf Vcm, 22 ft Vlbf)
HINT: Each bolt length is indicated in the illustration.
Bolt length:
A 106 mm (4.17 in.) for 12 mm head
B 114 mm (4.49 in.) for 14 mm head
(b) Connect the solenoid valve connector.
2. CONNECT PRESSURE AND SUCTION HOSES TO HYDRAULIC PUMP
(a) Connect the pressure hose with new gasket and unionbolt.
Torque: 64 N Vm (650 kgf Vcm, 47 ft Vlbf)
(b) Connect suction hose.
3. INSTALL RH NO.2 TIMING BELT COVER
(a) Install the four gaskets to the timing belt cover.
(b) Install the connector grommet to the timing belt cover.
(c) Install the timing belt cover with the five bolts.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
HINT (12 mm head bolt): Use bolts 106 mm (4.17 in.) in
length.
(d) Install the wire clamp to the timing belt cover.
(e) Install the cam position sensor wire to the wire clamp on
the timing belt cover.
(f) Install the cam position sensor connector to the ignition coil bracket.
4. INSTALL LH NO.2 TIMING BELT COVER (a) Install the two gaskets to the timing belt cover.
(b) Run the cam po sition sensor wire through the timing belt
cover hole.
(c) Install the timing belt cover and connector bracket with the three bolts.
(d) Connect the cam position sensor connector.
(e) In sta ll th e ca m po sitio n se n so r c onnector to the
connector bracket.
(f) Install the cam position sensor wire to the wire clamp on
the timing belt cover.
(g) Install the connector grommet to the timing belt cover.
CO±42
±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Pump)
WhereEverybodyKnowsYourName

5. INSTALL DRIVE BELT IDLER PULLEYInstall the idler pulley and cover plate with the pulley bolt.
Torque: 37 N Vm (380 kgf Vcm, 27 ft Vlbf)
6. CONNECT RADIATOR HOSE TO WATER INLET
7. INSTALL RH NO.3 TIMING BELT COVER
(a) Install the three gaskets to the timing belt cover.
(b) Fit portion A of the timing belt cover, matching it with the
lower high±tension cord cover.
(c) Install the timing belt cover with the three bolts.
8. INSTALL VSV FOR EVAP SYSTEM Install the VSV with the two bolts.
9. INSTALL LH NO.3 TIMING BELT COVER (a) Install the three gaskets to the timing belt cover.
(b) Install the cord grommet to the high±tension cord.
(c) Install the cord grommet to the timing belt cover.
(d) Fit portion A of the timing belt cover, matching it with the
lower high±tension cord cover.
(e) Install the timing belt cover with the four bolts.
10. INSTALL RH ENGINE WIRE COVER (a) Fit portions A and B of the engine wire cover, matchingthem with the lower high±tension cord cover and No.3
timing belt cover.
(d) Install the engine wire cover with the bolt.
±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Pump)CO±43
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11. INSTALL LH ENGINE WIRE COVER(a) Connect portions A and B engine wire cover to the wirebrackets.
(b) Set the VSV (for fuel pressure control system) wire in
original position.
(c) Fit portions C and D of the engine wire cover, matching them with the lower high±tension cord cover and No.3
timing belt cover.
(d) Install the engine wire cover with the two bolts.
12. INSTALL UPPER HIGH±TENSION CORD COVER (a) Fit portion A of the upper high±tension cover, matchingit with the top of the lower high±tension cord cover.
(b) Push the front side of the high±tension cord cover, and connect the front side claw groove of the upper
high±tension cord cover to the claw of the lower
high±tension cord cover.
(c) Install the upper high±tension cord cover with the two bolts.
13. INSTALL INTAKE AIR CONNECTOR (a) Connect the end portions of the intake air connector tothe throttle body and air cleaner hose.
(b) Tighten the two hose clamps.
(c) Install the bolt holding the intake air connector to the cylinder head cover.
(d) Connect the following hoses: (1) Air hose to ISC valve
(2) Air hose (from PS air control valve) to intake air con- nector
CO±44
±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Pump)
WhereEverybodyKnowsYourName

 
Compression at 250 rpm STD 1,226 kPa (12.5 kgf/cm2, 178 psi) or
more
 pressureLimit 981 kPa (10.0 kgf/cm2, 142 psi)  Difference of pressure between each cylinder  98 kPa (1.0 kgf/cm2, 14 psi) or less 

Timing belt
tensionerProtrusion from housing end10.5±11.5 mm (0.413±0.453 in.)
 Cylinder head Warpage Limit 0.10 mm (0.039 in.)
  Valve seat  
  Refacing angle  30
5, 45 5, 75 5
  Contacting angle  455
  Contacting width  1.0±1.4 mm (0.039±0.055 in.)
  Cylinder head bolt thread inside diameter STD 9.770±9.960 mm (0.3846±0.3921 in.)
   Limit 9.60 mm (0.3780 in.)
 Valve guideInside diameter6.010±6.030 mm (0.2366±0.2374 in.)
 bushing Outside diameter (for repair part) STD 11.048±11.059 mm (0.4350±0.4354
in.)
 O/S 0.05 11.098±11.109 mm (0.4369±0.4374 in.) ValveValve overall lengthSTD (Intake)94.95 mm (3.7382 in.)   (Exhaust) 96.90 mm (3.8150 in.)   Limit (Intake) 94.45 mm (3.7185 in.)   (Exhaust) 96.40 mm (3.7953 in.)
  Vale face angle  44.55
  Stem diameter Intake 5.970±5.985 mm (0.2350±0.2356 in.)
   Exhaust 5.965±5.980 mm (0.2348±0.2354 in.)
  Stem oil clearance STD (Intake) 0.025±0.060 mm (0.0010±0.0024 in.)
   (Exhaust) 0.030±0.065 mm (0.0012±0.0026 in.)
   Limit (Intake) 0.08 mm (0.0031 in.)
   (Exhaust) 0.10 mm (0.0039 in.)
  Margin thickness STD 1.0 mm (0.039 in.)
   Limit 0.5 mm (0.020 in.)
 Valve spring Squareness Limit 2.0 mm (0.079 in.)
  Free length  43.6 mm (1.717 in.)
  Installed tension at 32.9 mm (1.295 in.)  186±206 N (19.0±21.0 kgf, 41.9±46.3
lbf)
 

Valve lifter 

Lifter diameter 


 

30.966±30.976 mm (1.2191±2.2195
in.)
 


 


Lifter bore diameter 


 


31.000±31.016 mm (1.2205±1.2211
in.)
  Oil clearance STD 0.024±0.050 mm (0.0009±0.0020 in.)
   Limit 0.07 mm (0.0028 in.)
EG±206±
1UZ ± FE ENGINE ENGINE MECHANICAL
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