1991 LEXUS SC300 timing belt

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)
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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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Crankshaft Thrust clearance STD 0.020±0.220 mm (0.0008±0.0087 in.)
   Limit 0.30 mm (0.0118 in.)
  Thrust washer thickness  2.440±2.490 mm (0.0961±0.0980 in.)
  Main journal bore diameter on cylinder block  67.026±67.033 mm (2.8388±2.6391 in.)  
(with main bearing)
  
  
Main journal oil clearance
 
STD
 
0.026±0.045 mm (0.0010±0.0018 in.)   Limit 0.055 mm (0.0022 in.)  Main journal diameter  66.988±67.000 mm (2.6373±2.6378 in.) \
 \
Main bearing center wall thickness (Reference) 
   Mark 1 2.486±2.489 mm (0.0979±0.0980 in.)   Mark 2 2.489±2.492 mm (0.0980±0.0981 in.)   Mark 3 2.492±2.495 mm (0.0981±0.0982 in.)   Mark 4 2.495±2.498 mm (0.0982±0.0983 in.)
   Mark 5 2.498±2.501 mm (0.0983±0.0985 in.)
  Crank pin diameter  51.982±52.000 mm (2.0465±2.0472 in.)
  Circle runout Limit 0.08mm (0.0031 in.)
  Main journal taper and out±of±round Limit 0.02mm (0.0008 in.)
  Crank pin taper and out±of±round Limit 0.02mm (0.0008.in)
EGOC6±0C
TORQUE SPECIFICATION
 Part tightened  NVm kgf Vcm ft Vlbf
 No.1 idler pulley x Cylinder Block  34 350 25
 No.2 idler pulley x Cylinder block3435025
 Hydraulic pump x Cylinder block for 12 mm head 16 160 12

yy
for 14 mm head3031022 Crankshaft pulley x Crankshaft  245 2,500 181 Camshaft timing pulley x Camshaft  108 1,100 80 Timing belt tensioner x Oil pump  26 270 20 Spark plug x Cylinder head  18 180 13
 Drive belt tensioner x Cylinder block  16 160 12
 Generator x Generator bracket  37 380 27
 Generator x Cylinder block3738027
 Distributor housing x Cylinder head1818513
 Distributor rotor x Camshaft timing pulley3.83934 in.
lbf
 Distributor cap x Distributor housing3.83934 in.
lbf
 RH No.2 timing belt cover x Cylinder blockfor 12 mm head1818513
Drive belt idler pulley x Fan bracket3738027 
A/C compressor x Cylinder block4950036 A/C compressor x Fan bracket  49 500 36 A/C compressor stay x Oil filter bracket  29 300 22 Upper radiator support x Body  12 120 9 Exhaust manifold x Cylinder head  44 450 33
 Cylinder head x Cylinder block 1st 39 400 29
  2nd Turn 90 5  
 Camshaft bearing cap x Cylinder head  16 160 12
 Cylinder head cover x Cylinder head  5.9 60 52 in.Vlbf
Engine hanger x Cylinder head3738027 EGR pipe x RH exhaust pipe  18 185 13 Rear water bypass joint x Cylinder head  18 185 13
±
1UZ ± FE ENGINE ENGINE MECHANICALEG±209
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Front water bypass joint x Cylinder head  18 185 13
 Intake manifold x Cylinder head1818513
Delivery pipe x Intake manifold1818513 
Fuel return pipe x Fuel pressure regulator
  
35
 
360
 
26 Fuel inlet hose x Delivery pipe  39 400 29  for SST 33 340 24 Cold start injector x Air intake chamber  7.8 80 69 in.Vlbf Air intake chamber x Intake manifold  18 185 13 EGR pipe x Air intake chamber  18 185 13
 EGR pipe x RH cylinder head  18 185 13
 Cold start injector tube x Air intake chamber  15 150 11
 Union (for brake booster) x Air intake chamber  29 300 22
 Throttle body x Air intake chamber  18 185 13
 IAC valve x Air intake chamber  18 185 13
 EGR valve adaptor x Air intake chamber  18 185 13
 EGR valve x EGR valve adaptor  18 185 13
Timing belt rear plate x Cylinder head7.88069 in. Vlbf 
Water outlet housing x Water pump
  
18
 
185
 
13 Main bearing stud bolt x Cylinder block  15 150 11 Main bearing cap x Cylinder block for nut (1st) 27 275 20  (2nd) Turn 90 5  
  for bolt 49 500 36 Connecting rod cap x Connecting rod 1st 25 250 18
  2nd Turn 905  
 Rear oil seal retainer x Cylinder block  7.8 80 69 in.Vlbf
 Water seal plate x Cylinder block  14 145 10
 Generator bracket x Cylinder block  18 185 13
 Oil pump x Cylinder block 12 mm head 16 160 12
  14 mm head 30 310 22
 No.1 oil pan x Cylinder block 10 mm head 7.8 80 69 in. Vlbf
12 mm head1818513 
No.1 oil pan x Oil pump
  
7.8
 
80
 
69 in. Vlbf No.1 oil pan x Rear oil seal retainer  7.8 80 69 in. Vlbf Oil strainer x Cylinder block  7.8 80 69 in. Vlbf Oil strainer x Oil pump  7.8 80 69 in. Vlbf Oil pan baffle plate x No.1 oil pan  7.8 80 69 in. Vlbf No.1 oil pan x No.2 oil pan  7.8 80 69 in. Vlbf
 Water pump x Cylinder block  18 185 13
 Water bypass pipe x Cylinder Block  18 185 13
 Knock sensor x Cylinder block  44 450 33
 Starter x Cylinder block  39 400 29
 Engine mounting bracket x Cylinder block  37 380 27
 Drive plate x Crankshaft  98 1,000 72
 Transmission x Cylinder block  57 580 42
 Transmission x No.1 oil pan  39 400 29
Drive plate x Torque converter3334025 Transmission oil cooler pipe x Transmission for union nut 34 350 25 Rear engine mounting member x Body  25 250 19\
 \
Rear engine mounting member x Rear engine mounting insulator1313510
EG±210±
1UZ ± FE ENGINE ENGINE MECHANICAL
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The 1 UZ±FE engine has 8±cylinders in a V±arrangement at a bank an\
gle of 905. From the front of the RH
bank cylinders are numbered 2 ± 4 ± 6 ± 8, and from the front of t\
he LH bank cylinders are 1 ± 3 ± 5 ± 7.
The crankshaft is supported by 5 bearings inside the crankcase. These beari\
ngs are made of a copper and
lead alloy.
The crankshaft is integrated with 8 weights for balance. Oil holes are plac\
ed in the center of the crankshaft
to supply oil to the connecting rods, bearing, pistons and other component\
s.
The ignition order is 1 ± 8 ± 4 ± 3 ± 6 ± 5 ± 7 ± 2. T\
he cylinder head is made of alminum alloy, with a cross
flow type intake and exhaust layout and with pent±roof type combustion chambers. The spark plugs are
located in the center of the combustion chambers.
At the front and rear of the intake manifold, a water passage has been p\
rovided which connects the RH
and LH cylinder heads.
Exhaust and intake valves are equipped with irregular pitch springs made\
of special valve spring carbon
steel which are capable of functioning at all engine speeds.
The RH and LH intake camshaft are driven by a timing belt, and a gear on\
the intake camshaft engages
with a gear on the exhaust camshaft to drive it. The cam journal is supp\
orted at 5 (intake) or 4 (exhaust)
places between the valve lifters of each cylinder and on the front end o\
f the cylinder head. Lubrication of
the cam journals and gears is accomplished by oil being supplied through th\
e oiler port in the center of the
camshaft.
Adjustment of the valve clearance is done by means of an outer shim type\
system, in which valve adjusting
shims are located above the valve lifters. This permits replacement of the sh\
ims without removal of the
camshafts.
Pistons are made of high temperature±resistant aluminum alloy, and a depression is built into the piston
head to prevent interference with the valves.
Piston pins are the full±floating type, with the pins fastened to neither the piston boss nor the connecting
rods. Instead, snap rings are fitted on both ends of the pins, preventing the\
pins from falling out.
The No.1 compression ring is made of steel and the No.2 compression ring\
is made of cast iron. The oil
ring is made of a combination of steel and stainless steel. The outer diamet\
er of each piston ring is slightly
larger than the diameter of the piston and the flexibility of the rings allows them to hug the cylinder walls
when they are mounted on the piston. Compression rings No.1 and No.2 work to\
prevent gas leakage from
the cylinder and the oil ring works to scrape oil off the cylinder walls to prevent it from entering the combus-
tion chambers.
The cylinder block is made of aluminum alloy with a bank of 90 5. Cast iron cylinders are installed inside
the cylinder block. It has 8 cylinders which are approximately twice the le\
ngth of the piston stroke. The top
of each cylinder is closed off by the cylinder head and the lower end of the cylinders becomes the crank-
case, in which the crankshaft is installed. In addition, the cylinder block c\
ontains a water jacket, through
which coolant is pumped to cool the cylinders.
The No.1 and No.2 oil pans are bolted onto the bottom of the cylinder bl\
ock. The No.1 oil pan is made of
aluminum alloy. The No.2 oil pan is an oil reservoir made of pressed steel sheet. An o\
il level sensor is
installed in the No.1 oil pan (If oil level drops below a set level, a warning light\
s up.). And oil pan baffle plate
keeps sufficient oil in the bottom of the No.2 oil pan even when the vehicle is t\
ilted. This dividing plate also
prevents the oil from marking waves when the vehicle is stopped suddenly\
and the oil shifts away from the
oil pump suction pipe.
Plastic region tighten bolts are used for the cylinder head, main bearin\
g cap and connecting rod.
EG±4
±
1UZ±FE ENGINE ENGINE MECHANICAL
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2. INSPECT AND CLEAN AIR FILTER
(a) Visually check that the air filter is not excessively damagedor only.
If necessary, replace the air filter.
(b) Clean the air filter with compressed air. First blow from the inside thoroughly, then blow off the out-
side of the air filter.
3. REINSTALL AIR FILTER
EG1KB±02
HIGH±TENSION CORDS INSPECTION
1. REMOVE NO.3 TIMING BELT COVERS (See steps 10 to 14 on pages EG±16)
2. REMOVE HIGH±TENSION CORDS (See step 1 on page IG±16)
NOTICE: Pulling on or bending the cords may damage the con-
ductor inside.
3. INSPECT HIGH±TENSION CORD RESISTANCE Using an ohmmeter, measure the resistance.
Maximum resistance:
25 k
per cord
If the resistance is greater than maximum, replace the cord.
4. REINSTALL HIGT±TENSION CORDS (See step 1 on page IG±19)
5. REINSTALL NO.3 TIMING BELT COVERS (See steps 28 to 30 on pages EG±29)
EG±12
±
1UZ±FE ENGINE ENGINE MECHANICAL
WhereEverybodyKnowsYourName

(b) Remove the bolt holding the intake air connector to thecylinder head cover.
(c) Remove the 2 hose clamps.
(d) Disconnect the intake air connector from the throttle body and air cleaner hose, and remove the intake air connector.
6. REMOVE UPPER HIGH±TENSION CORD COVER
(a) Remove the 2 bolts.
(b) Disconnect the front side claw groove of the upper cord cover
from the claw of lower cord cover, and remove the upper cord
cover.
7. REMOVE RH ENGINE WIRE COVER Remove the bolt and engine wire cover.
8. REMOVE LH ENGINE WIRE COVER Remove the 2 bolts and engine wire cover.
9. REMOVE VSV FOR EVAP SYSTEM Remove the 2 bolts, and disconnect the VSV from the cylin-
der head cover and timing belt cover.
±
1UZ±FE ENGINE ENGINE MECHANICALEG±15
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10. REMOVE RH NO.3 TIMING BELT COVERRemove the 3 bolts, timing belt cover and 3 gaskets.
11. DISCONNECT FUEL INLET HOSE FROM LH DELIVERY PIPE
Remove the pulsation damper and 2 gaskets, and discon-
nect the fuel inlet hose from the delivery pipe.
CAUTION:
w Put a shop towel under the delivery pipe.
w Slowly loosen the union bolt.
12. D I S C O N N E C T F U E L R E T U R N H O S E F R O M F U E L
RETURN PIPE
13. DISCONNECT PCV HOSE FROM LH CYLINDER HEAD
14. REMOVE LH NO.3 TIMING BELT COVER
(a) Remove the 4 bolts.
(b) Disconnect the cord grommet from the timing belt cover, and remove the timing belt cover and 3 gaskets.
(c) Remove the cord grommet from the high±tension cord.
15. DISCONNECT HEATER WATER VALVE FROM BODY
(a) Disconnect the VSV connector.
(b) Remove the bolt holding the engine wire clamp to the water valve bracket.
(c) Remove the 2 bolts, and disconnect the water valve and bracket assembly.
16. REMOVE THROTTLE BODY
(a) Disconnect the following connectors: (1) Throttle position sensor connector
(2) w/ TRAC:
Sub±throttle position sensor connector
(3) w/ TRAC:
Sub±throttle actuator connector
EG±16
±
1UZ±FE ENGINE ENGINE MECHANICAL
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