1991 LEXUS SC400 exhaust

3. INSPECT EGR VALVECheck for sticking and heavy carbon deposits.
If a problem is found, replace the EGR valve assembly.
4. REINSTALL EGR VALVE (a) Place a new gasket on the EGR valve adaptor.
NOTICE:
w Do not touch the adaptor and EGR valve surfaces of the
gasket with your hand.
w Align the port holes of the gasket and adaptor.
Be careful of the installation direction.
(b) Install the EGR valve with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(c) Install the vacuum modulator bracket to the EGR valve.
(d) Connect the following hoses:
(1) Vacuum hose (from VSV) to EGR valve
(2) Vacuum hose (from VSV) to EGR vacuum modula- tor
(3) Vacuum hose (from EGR vacuum modulator) to EGR valve
(4) Water by±pass hose (from ISC valve) to the EGR
valve
(5) Water by±pass hose (from rear water by±pass joint) to the EGR valve
5. REFILL WITH ENGINE COOLANT (See page CO±7)
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±25
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THREE±WAY CATALYST (TWC) SYSTEM
DESCRIPTION
To reduce HC, CO and NOx emissions, they are oxidized, reduced and convert\
ed to nitrogen (N), carbon diox-
ide (CO) and water (HO) by the catalyst.
OPERATION
INSPECTION OF EXHAUST PIPE
ASSEMBLY
1. CHECK CONNECTIONS FOR LOOSENSESS ORDAMAGE
2. CHECK CLAMPS FOR WEAKNESS, C RACKS OR
DAMAGE
INSPECTION OF CATALYTIC
CONVERTER
CHECK FOR DENTS OR DAMAGE
If any part of the protector is damaged or dented to the extent
that is contacts the catalyst, repair or replace it.
INSPECTION OF HEAT INSULATOR
1. CHECK HEAT INSULATOR FOR DAMAGE
2. CHECK FOR ADEQUATE CLEARANCE BETWEENCATALYTIC CONVERTER AND HEAR INSULATOR
±
EMISSION CONTROL SYSTEMS Three±way Catalyst (TWC) SystemEC±17
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COMPONENTS
REPLACEMENT OF CATALYTIC
CONVERTERS
(Front Catalytic Converter)
1. REMOVE CATALYTIC CONVERTER (FRONT)(a) Check that the converter is cool.
(b) Remove the two bolts and nuts holding the catalyticconverters to the front exhaust pipe.
(c) Disconnect the front exhaust pipe from the catalytic converter, and remove the gasket.
(d) Remove the four nuts holding the catalytic converter to the exhaust manifold.
2. REINSTALL CATALYTIC CONVERTER (a) Install a new gasket and the catalytic converter to theexhaust manifold with four new nuts.
Torque: 62 N Vm (630 kgf Vcm, 46 ft Vlbf)
(b) Install a new gasket to front end of the front exhaust
pipe, and torque the front exhaust pipe to the catalytic
converter.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
EC±18±
EMISSION CONTROL SYSTEMS Three±way Catalyst (TWC) System
WhereEverybodyKnowsYourName

(Rear Catalytic Converter)
1. (USA Spec.)REMOVE SUB±OXYGEN SENSOR
Remove the two nuts and sub±oxygen sensor from the front
exhaust pipe.
2. REMOVE REAR CATALYTIC CONVERTER (FRONT EXHAUST PIPE)
(a) Remove the two bolts and nuts holding the front exhaust
pipe to the center exhaust pipe.
(b) Remove the two bolts and nuts holding the front exhaust
pipe to the front catalytic converter, and remove the front
exhaust pipe and two gaskets.
3. REINSTALL REAR CATALYTIC CONVERTER (FRONT EXHAUST PIPE)
Install the two new gaskets, the front exhaust pipe with the
four bolts and new nuts.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
4. (USA Spec.)
REINSTALL SUB±OXYGEN SENSOR
Install the new gasket, the sub±oxygen sensor to the front ex-
haust pipe with the two nuts.
Torque: 18 N Vm (180 kgf Vcm, 13 ft Vlbf)
±
EMISSION CONTROL SYSTEMS Three±way Catalyst (TWC) SystemEC±19
WhereEverybodyKnowsYourName

SERVICE SPECIFICATIONS
SERVICE DATA
EG065±0A Tune±up Battery specific gravity  1.27±1.29
    (when fully charged at 205C (68 5F))
  High±tension cord resistance Limit 25 k
per cord
  Valve clearance (Cold) Intake 0.15±0.25 mm (0.006±0.010 in.)
   Exhaust 0.25±0.35 mm (0.010±0.014 in.)
Valve clearance adjusting shimNo.012.500 mm (0.0984 in.)   No.62 2.525 mm (0.0994 in.)   No.63 2.550 mm (0.1004 in.)   No.64 2.575 mm (0.1014 in.)   No.06 2.600 mm (0.1024 in.)
   No.65 2.625 mm (0.1033 in.)
   No.66 2.650 mm (0.1043 in.)
   No.67 2.675 mm (0.1053 in.)
   No.13 2.700 mm (0.1063 in.)
   No.68 2.725 mm (0.1073 in.)
   No.18 2.750 mm (0.1083 in.)
No.192.775 mm (0.1093 in.)   No.23 2.800 mm (0.1102 in.)   No.70 2.825 mm (0.1112 in.)   No.28 2.850 mm (0.1122 in.)   No.71 2.875 mm (0.1132 in.)
   No.33 2.900 mm (0.1142 in.)
   No.72 2.925 mm (0.1152 in.)
   No.38 2.950 mm (0.1161 in.)
   No.73 2.975 mm (0.1171 in.)
   No.43 3.000 mm (0.1181 in.)
No.743.025 mm (0.1191 in.)   No.48 3.050 mm (0.1201 in.)   No.75 3.075 mm (0.1211 in.)   No.51 3.100 mm (0.1220 in.)   No.76 3.125 mm (0.1230 in.)   No.77 3.150 mm (0.1240 in.)
   No.78 3.175 mm (0.1250 in.)
   No.56 3.200 mm (0.1260 in.)
   No.79 3.225 mm (0.1270 in.)
   No.80 3.250 mm (0.1280 in.)
   No.81 3.275 mm (0.1289 in.)
No.613.300 mm (0.1299 in.)  Ignition timing  8 ± 12 5 BTDC @ idle 


 


 


 

(w/ Terminals TE1 and E1 connected
of DLC1)
  Idle speed  700
+ 50 rpm
 Intake at idle speed  60 kPa (450 mmHg. 17.7 in.Hg)
 manifold
 vacuum   
±
1UZ ± FE ENGINE ENGINE MECHANICALEG±205
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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
WhereEverybodyKnowsYourName

 
Camshaft Thrust clearance STD 0.040±0.090 mm (0.0016±0.0035 in.)
   Limit 0.12 mm (0.0047 in.)
  Journal oil clearance  
  Exhaust camshaft thrust portion STD 0.025±0.061 mm (0.0010±0.0024 in.)  
Others
 
STD
 
0.030±0.067 mm (0.0012±0.0026 in.)   
Limit
 
0.10 mm (0.0039 in.)  Journal diameter  
  Exhaust camshaft thrust portion  23.959±23.975 mm (0.9433±0.9539 in.)  Others  26.954±26.970 mm (1.0612±1.0618 in.)  Circle runout Limit 0.08 mm (0.0031 in.)  Cam lobe height STD (Intake) 41.710±41.810 mm (1.6421±1.6461 in.)   (Exhaust) 41.910±42.010 mm (1.6500±1.6539 in.)   Limit (Intake) 41.56 mm (1.6362 in.)
   (Exhaust) 41.76 mm (1.6441 in.)
  Camshaft gear backslash STD 0.020±0.200 mm (0.0008±0.0079 in.)
   Limit 0.30 mm (0.0188 in.)
  Camshaft gear spring end free distance  18.2±18.8 mm (0.712±0.740 in.)
 Air intake Warpage Limit 0.15 mm (0.0059 in.)
 chamber
 Manifold Warpage Limit (Intake) 0.15 mm (0.0059 in.)
   (Exhaust) 1.00 mm (0.0394 in.)
 Cylinder block Cylinder head surface warpage Limit 0.07 mm (0.0028 in.)
  Cylinder bore±diameter Mark 1 87.500±87.510 mm (3.4449±3.4453 in.)
   Mark 2 87.510±87.520 mm (3.4453±3.4457 in.)
   Mark 3 87.520±87.530 mm (3.4457±3.4461 in.)
Limit87.73 mm (3.4539 in.)  
Main journal bore diameter (Reference)
 
Mark 00
 
72.000 mm (2.8346 in.)   Mark 01 72.001 mm (2.8347 in.)   Mark 02 72.002 mm (2.8347 in.)   Mark 03 72.003 mm (2.8348 in.)   Mark 04 72.004 mm (2.8348 in.)   Mark 05 72.005 mm (2.8348 in.)   Mark 06 72.006 mm (2.8349 in.)   Mark 07 72.007 mm (2.8349 in.)
   Mark 08 72.008 mm (2.8350 in.)
   Mark 09 72.009 mm (2.8350 in.)
   Mark 10 72.010 mm (2.8350 in.)
   Mark 11 72.011 mm (2.8351 in.)
   Mark 12 72.012 mm (2.8351 in.)
   Mark 13 72.013 mm (2.8352 in.)
   Mark 14 72.014 mm (2.8352 in.)
   Mark 15 72.015 mm (2.8352 in.)
   Mark 16 72.016 mm (2.8353 in.)
 Main bearing cap stud bolt tension portion diameter
   STD 7.500±7.600 mm (0.2953±0.2992 in.)
   Limit 7.40 mm (0.2913 in.)
±
1UZ ± FE ENGINE ENGINE MECHANICALEG±207
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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
WhereEverybodyKnowsYourName