1991 LEXUS SC400 engine oil

(d) Clean the crank pin and bearing.
(e) Check the crank pin and bearing for pitting and scratches.If the crank pin or bearing is damaged, replace the bearings.
If necessary, replace the crankshaft.
(f) Lay a strip of Plastigage across the crank pin.
(g) Install the connecting rod cap with the 2 bolts. (See step 7 on page EG±183)
Torque:
1st 25 N Vm (250 kgf Vcm, 18 ft Vlbf)
2nd Turn 90 5
NOTICE: Do not turn the crankshaft.
(h) Remove the 2 bolts, connecting rod cap and lower bearing. (See procedure (b) and (c) above)
(i) Measure the Plastigage at its widest point.
Standard oil clearance: 0.027 ± 0.053 mm (0.0011 ± 0.0021 in.)
Maximum oil clearance: 0.065 mm (0.0026 in.)
If the oil clearance is greater than maximum, replace the
bearings. If necessary, replace the crankshaft.
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1UZ±FE ENGINE ENGINE MECHANICALEG±157
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6. REMOVE MAIN BEARING CAPS AND CHECK OILCLEARANCE
(a) Remove the 10 main bearing cap bolts.
(b) Uniformly loosen and remove the 20 main bearing cap nuts
in several passes, in the sequence shown.
(c) Using 2 screwdrivers, pry out the main bearing cap, and remove the 5 main bearing caps, lower bearings and lower
thrust washers (No.3 main bearing cap only).
NOTICE: Be careful not to damage the cylinder block.
HINT:
wKeep the lower bearing and main bearing cap together.
w Arrange the main bearing caps and lower thrust
washers in correct order.
(d) Lift out the crankshaft.
(e) Remove the 2 upper thrust washers. HINT:
wArrange the upper thrust washers in correct order.
w Keep the upper bearings together with the cylinder
block.
(f) Clean each main journal and bearing.
(g) Ch e ck ea ch ma in jo u rn a l an d be a rin g fo r pittin g an d scratches.
If the journal or bearing is damaged, replace the bearings. If
necessary, replace the crankshaft.
EG±160
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(h) Install the 5 main bearing caps with the 20 nuts and ten bolts.
Do not install the crankshaft.
(See step 4 on page EG±180)
Torque:
Nut1st 27 N Vm (275 kgf Vcm, 20 ft Vlbf)
2nd Turn 90 5
Bolt 49 N Vm (500 kgf Vcm, 36 ft Vlbf)
(i) Using a cylinder gauge, measure the inside diameter of the
the main bearing.
Bearing inside diameter:
67.026 ± 67.033 mm (2.6388 ± 2.6391 in.)
(j) Using a, micrometer measure the diameter of the mainjournal
Main journal diameter:
66.988 ± 67.000 mm (2.6373 ± 2.6378 in.)
(k) Subtract the main journal diameter measurement from themain bearing inside diameter measurement.
Standard clearance:
0.026 ± 0.045 mm (0.0010 ± 0.0018 in.)
Maximum clearance: 0.055 mm (0.0022 in.)
If the oil clearance is greater than maximum, replace the
bearings. If necessary, replace the crankshaft.
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1UZ±FE ENGINE ENGINE MECHANICALEG±161
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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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1UZ±FE ENGINE ENGINE MECHANICALEG±167
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(b) Remove the 2 side rails and oil ring by hand.HINT: Arrange the piston rings in correct order only.
3. DISCONNECT CONNECTING ROD FROM PISTON
(a) Using a small screwdriver, pry out the 2 snap rings.
(b) Gradually heat the piston to approx. 60
C (140
F).
(c) Using a plastic±faced hammer and brass bar, lightly tap out the piston pin and pin and remove the connecting rod.
EG±168
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2. INSPECT PISTON
A. Inspect piston oil clearanceHINT: There are 3 sizes of the standard piston diameter,
marked ª1º, ª2º and ª3º accordingly. The mark is stamped on
the piston top.
(a) Using a micrometer, measure the piston diameter at ring angles to the piston pin center line, 49 mm (1.93 in.) f rom the
piston head.
Piston diameter:
Mark ª1º87.470 ± 87.480 mm (3.4437 ± 3.4441 in.)
Mark ª2º 87.480 ± 86.490 mm (3.4441 ± 3.4445 in.)
Mark ª3º 87.490 ± 87.500 mm (3.4445 ± 3.4449 in.)
(b) Measure the cylinder bore diameter in the thrust directions. (See step 4 on page EG±xxx)
(c) Subtract the piston diameter measurement from the cylinder bore diameter measurement.
Standard oil clearance:
0.020 ± 0.040 mm (0.0008 ± 0.0016 in.)
Maximum oil clearance: 0.06 mm (0.0024 in.)
If the oil clearance is greater than maximum, replace all the
8 pistons. If necessary, replace the cylinder block.
HINT (Use new cylinder block):
wUse a piston with the same number mark as the cylinder
diameter marked on the cylinder block.
w The shape of the piston varies for the RH and LH banks.
The RH piston is marked with ªRº, the LH piston with ªLº.
EG±170±
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B. Inspect piston ring groove clearanceUsing a feeler gauge, measure the clearance between new
piston ring and the wall of the ring groove
Ring groove clearance:
No.10.020 ± 0.060 mm (0.0008 ± 0.0024 in.)
No.2
0.015 ± 0.055 mm (0.0006 ± 0.0022 in.)
If the clearance is not as specified, replace the piston.
C. Inspect piston ring and gap
(a) Insert the piston ring into the cylinder bore.
(b) Using a piston, push the piston ring a little beyond the bottom
of the ring travel, 105 mm (4.13 in.) from the top of the cylinder
block.
(c) Using a feeler gauge, measure the end gap.
Standard end gap: No.10.250 ± 0.450 mm (0.0098 ± 0.0177 in.)
No.2 0.350 ± 0.600 mm (0.0138 ± 0.0236 in.)
Oil (Side rail)
0.160 ± 0.500 mm (0.0059 ± 0.0197 in.)
Maximum end gap: No.11.05 mm (0.0413 in.)
No.2 1.20 mm (0.0472 in.)
Oil (Side rail) 1.10 mm (0.0433 in.)
If the end gap is greater than maximum, replace the piston
ring. If the end gap is greater than maximum, even with a new
piston ring, replace the cylinder block.
D. Inspect piston pin fit At 60 5C (140 5F), you should be able to push the piston pin
into the piston pin hole with your thumb.
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1UZ±FE ENGINE ENGINE MECHANICALEG±171
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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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