check engine LEXUS SC400 1991 Service Repair Manual

7. IF NECESSARY, REPLACE MAIN BEARING CAP STUDBOLTS
(a) Using the 2 main bearing cap nuts, remove the stud bolt.
(b) Apply a light coat of engine oil on the threads and under
flange of new stud bolts.
(c) Using the 2 main bearing cap nuts, install the stud bolt.
Torque: 15 N Vm (150 kgf Vcm, 11 ft Vlbf)
HINT: Stud bolts come in lengths of 90.0 mm (3.543 in.) and
101.5 mm (3.996 in.). Install the 101.5 mm (3.996 in.) bolts
in inside positions. Install the 90.0 mm (3.543 in.) bolts in out-
side positions.
PISTON AND CONNECTING ROD
DISASSEMBLY
EG0BV±06
1. CHECK FIT BETWEEN PISTON AND PISTON PIN
Try to move the piston back and forth on the piston pin.
If any movement is felt, replace the piston and pin as a set.
2. REMOVE PISTON RINGS
(a) Using a piston ring expander, remove the 2 compression rings.
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3. INSPECT CONNECTING ROD
A. Inspect connecting rod alignmentUsing a rod aligner and feeler gauge, check the connecting
rod alignment.
wCheck for bend.
Maximum bend:
0.05 mm (0.0020 in.) per 100 mm (3.94 in.)
If bend is greater than maximum, replace the connecting rod
assembly.
wCheck for twist
Maximum twist:
0.15 mm (0.0059 in.) per 100 mm (3.94 in.)
If twist is greater than maximum, replace the connecting rod
assembly.
B. Inspect piston pin oil clearance
(a) Using a caliper gauge, measure the inside diameter of the connecting rod bushing.
Bushing inside diameter:
22.005 ± 22.017 mm (0.8663 ± 0.8668 in.)
(b) Using a micrometer, measure the piston pin diameter.
Piston pin diameter:21.997 ± 22.009 mm (0.8660 ± 0.8665 in.)
(c) Subtract the piston pin diameter measurement from thebushing inside diameter measurement.
Standard oil clearance:
0.005 ± 0.011 mm (0.0002 ± 0.0004 in.)
Maximum oil clearance: 0.05 mm (0.0020 in.)
If the oil clearance is greater than maximum, replace the
bushing. If necessary, replace the piston and piston pin as a
set.
EG±172
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C. If necessary, replace connecting rod bushing
(a) Using SST and a press, press out the bushing.SST 09222±30010
(b) Align the oil holes of a new bushing and the connecting rod.
(c) Using SST and a press, press out the bushing SST 09222±30010
(d) Using a pin hole grinder, hone the bushing to obtain the standard specified clearance (see step B above) between
the bushing and piston pin.
(e) Check the piston pin fit at normal room temperature. Coat the piston pin with engine oil, and push it into the con-
necting rod with your thumb.
D. Inspect connecting rod bolts Using a vernier caliper, measure the tension portion of of the
connecting rod bolt.
Standard diameter:
7.200 ± 7.300 mm (0.2835 ± 0.2874 in.)
Maximum diameter: 7.00 mm (0.2756 in.)
HINT: If the tension portion diameter is less than minimum,
replace the connecting rod bolt.
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CRANKSHAFT INSPECTION
EG0BY±0D
1. INSPECT CRANKSHAFT FOR CIRCLE RUNOUT
(a) Place the crankshaft 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
crankshaft.
2. INSPECT MAIN JOURNALS AND CRANK PINS
(a) Using a micrometer, measure the diameter of each main journal and crank pin.
Main journal diameter:
66.988 ± 67.000 mm (2.6373 ± 2.6378 in.)
Crank pin diameter: 51.982 ± 52.000 mm (2.0465 ± 2.0472 in.)
If the diameter is not as specified, check the oil clearance
(See steps 3 or 6 on page EG±156 or 160). If necessary, re-
place the crankshaft.
(b) Ch e ck ea ch ma in jo u rn a l an d cra n k pin fo r t aper and
out±of±round as shown.
Maximum taper and out±of±round:
0.02 mm (0.0008 in.)
If the taper and out±of±round is greater than maximum, re-
place the crankshaft.
EG±174
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(a) Apply a light coat of engine oil on the threads and under themain bearing cap nuts.
(b) Install and uniformly tighten the 20 main bearing cap nuts in
several passes, in the sequence shown.
Torque: 27 N Vm (275 kgf Vcm, 20 ft Vlbf)
If any one of the main bearing cap nuts does not meet the
torque specification, replace the main bearing cap stud bolt.
(c) Mark the front of the main bearing cap nut with paint.
(d) Retighten the main bearing cap bolts 90
in the numerical
order shown.
(e) Check that the painted mark is now at a 90
angle to the front.
C. Install main bearing cap bolts
(a) Install a new seal washer to the main bearing cap bolt.
(b) Install and uniformly tighten the 10 main bearing cap bolts.
Torque: 49 N Vm (500 kgf Vcm, 36 ft Vlbf)
(c) Check that the crankshaft turns smoothly.
5. CHECK CRANKSHAFT THRUST CLEARANCE
Using a dial indi cator, measure the thrust clearance while pry-
ing the crankshaft back and forth with a screwdriver.
Standard thrust clearance:
0.020 ± 0.220 mm (0.0008 ± 0.0087 in.)
Maximum thrust clearance: 0.30 mm (0.0118 in.)
If the thrust clearance is greater than maximum, replace the
thrust washers as a set.
Thrust washer thickness:2.440 ± 2.490 mm (0.0961 ± 0.0980 in.)
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6. INSTALL PISTON AND CONNECTING ROD ASSEMBLESUsing a piston ring compressor, push the correctly numbered
piston and connecting rod assemblies into each cylinder with
the front mark of the piston facing forward.
NOTICE: The shape of the piston varies for the RH and LH
banks. The RH piston is marked with ªRº, the LH piston
with ªLº.
7. INSTALL CONNECTING ROD CAPS
A. Place connecting rod cap on connecting rod
(a) Match the numbered connecting rod cap with the connecting rod.
(b) Align the pin groove of the connecting rod cap with the pins of the connecting rod, and install the connecting rod.
(c) Check that the outside mark of the connecting rod cap is facing in correct direction.
EG±182
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B. Install connecting rod cap boltsHINT:
wThe connecting rod cap bolts are tightened in 2
progressive steps (steps (b) and (d)).
w If any one of the connecting rod cap bolts is broken or
deformed, replace it.
(a) Apply a light coat of engine oil on the threads and under the heads of the connecting rod cap bolts.
(b) Install and alternately tighten the 2 connecting rod cap bolts
in several passes.
Torque: 25 N Vm (250 kgf Vcm, 18 ft Vlbf)
If any one of the connecting rod cap bolts does not meet the
torque specification, replace the connecting rod cap bolts.
(c) Mark the front of the connecting cap bolt with paint.
(d) Retighten the cap nuts 90
as shown.
(e) Check that the painted mark is now at a 90
angle to the front.
(f) Check that the crankshaft turns smoothly.
8. CHECK CONNECTING ROD OIL CLEARANCE
Using a dial indicator, measure the thrust clearance while
moving the connecting rod back and forth.
Standard thrust clearance:
0.160 ± 0.290 mm (0.0063 ± 0.0138 in.)
Maximum thrust clearance: 0.35 mm (0.0138 in.)
If the thrust clearance is greater than maximum, replace the
connecting rod assembly(s). If necessary, replace the crank-
shaft.
Connecting rod thickness:22.880 ± 22.920 mm (0.9008 ± 0.9024 in.)
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7. INSTALL TAILPIPE
(a) Install the hook of the tailpipe to the ring on the tailpipebracket.
(b) Install a new gasket and tailpipe to the center exhaust pipe with 2 bolts. Install the 2 tailpipes.
Torque: 19 N Vm (195 kgf Vcm, 14 ft Vlbf)
8. INSTALL TWC (FRONT)
Using a 14 mm deep socket wrench, install a new gasket and
the TWC with 3 new nuts. Install the 2 TWC.
Torque: 62 N Vm (630 kgf Vcm, 46 ft Vlbf)
9. INSTALL FRONT EXHAUST PIPE
(a) Temporarily install the pipe support bracket with the 4 bolts.
(b) Temporarily install 3 new gaskets and the exhaust pipe with
the 6 bolts and nuts.
(c) Tighten the 4 bolts and nuts holding the TWC to the front exhaust pipe.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
(d) Tighten the 2 bolts and nuts holding the front exhaust pipe to
the center exhaust pipe.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
(e) Tighten the 4 bolts holding the pipe support bracket to the
transmission.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
10. INSTALL SUB HEATED OXYGEN SENSORS
Install the 2 oxygen sensors to the front exhaust pipe.
Torque: 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
HINT:
w Before installing the oxygen sensor, twist the sensor
wire counterclockwise 3 1/2 turns.
w After installing the oxygen sensor, check that the sensor
wire is not twisted. If it is twisted, remove the oxygen
sensor and reinstall it.
EG±194
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34. FILL WITH ENGINE COOLANT
35. FILL WITH ENGINE OIL
36. START ENGINE AND CHECK FOR LEAKS
37. CHECK TRANSMISSION FLUID LEVEL
38. PERFORM ENGINE ADJUSTMENT(See Tune±Up on pages EG±9 to 34)
39. INSTALL ENGINE UNDER COVER
40. INSTALL HOOD
41. PERFORM ROAD TEST Check for abnormal noise, shock slippage, correct shift
points and smooth operation.
42. RECHECK ENGINE COOLANT AND OIL LEVELS
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DISASSEMBLY OF CYLINDER BLOCK
(See Components on page EM±131)
1. REMOVE REAR OIL SEAL RETAINER (a) Remove the seven bolts.
(b) Remove the oil seal retainer by prying the portions
between the oil seal retainer and main bearing cap with
a screwdriver.
(c) Remove the O±ring.
2. CHECK CONNECTING ROD THRUST CLEARANCE Using a dial indicator, measure the thrust clearance while
moving the two connecting rods back and forth.
Standard thrust clearance: 0.160±0.290 mm
(0.0063±0.0114 in.)
Maximum thrust clearance: 0.35 mm (0.0138 in.)
If the thrust clearance is greater than maximum, replace the
connecting rod assembly(s). If necessary, replace the crank-
shaft.
Connecting rod thickness: 22.880±22.920 mm (0.9008±0.9024 in.)
3. REMOVE CONNECTING ROD CAPS AND CHECK OILCLEARANCE
(a) Using a punch or numbering stamp, place thematchmarks on the connecting rod and cap to ensure
correct reassembly.
(b) Using SST, remove the two connecting rod bolts.
SST 09011±38121
(c) Using the two removed connecting rod bolts, remove the connecting rod cap and lower bearing by wiggling
the connecting rod cap right and left.
HINT: Keep the lower bearing inserted with the connecting rod cap.
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ENGINE MECHANICAL Cylinder BlockEM±135
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