lock LEXUS SC400 1991 Service Repair Manual

HINT: If using a standard bearing, replace with one having
the same number. If the number of the bearing cannot be de-
termined, select the correct bearing by adding together the
numbers imprinted on the cylinder block and crankshaft, then
refer to the table below for the appropriate bearing number.
There are five sizes of standard bearings, marked º1º, º2º, º3º\
,
º4º and º5º accordingly.
  Total number ºº: Number mark
Cylinder block (A) +0±23±56±89±1112±14 Crankshaft (B) = Use bearing º1º º2º º3º º4º º5º
EXAMPLE: Cylinder block º3º (A)
+ Crankshaft º4º (B)
= Total number 7 (Use bearing º3º)
(Reference)
Cylinder block main journal bore diameter (A):Mark º0º 66.020±66.022 mm (2.59921±2.59929 in.)
Mark º1º 66.022±66.024 mm (2.59929±2.59937 in.)
Mark º2º 66.024±66.026 mm
(2.59937±2.59945 in.)
Mark º3º 66.026±66.028 mm
(2.59945±2.59953 in.)
Mark º4º 66.028±66.030 mm
(2.59953±2.59961 in.)
Mark º5º 66.030±66.032 mm
(2.59961±2.59969 in.)
Mark º6º 66.032±66.034 mm
(2.59969±2.59976 in.)
Mark º7º 66.034±66.036 mm
(2.59976±2.59984 in.)
U/S 0.25 66.020±66.036 mm
(2.59921±2.59984 in.)
Crankshaft main journal diameter (B):
Mark º0º 61.998±62.000 mm(2.44087±2.44095 in.)
Mark º1º 61.996±61.998 mm (2.44079±2.44087 in.)
Mark º2º 61.994±61.996 mm (2.44071±2.44079 in.)
Mark º3º 61.992±61.994 mm (2.44063±2.44071 in.)
Mark º4º 61.990±61.992 mm (2.44055±2.44063 in.)
Mark º5º 61.988±61.990 mm
(2.44047±2.44055 in.)
Mark º6º 61.986±61.988 mm
(2.44039±2.44047 in.)
Mark º7º 61.984±61.986 mm
(2.44031±2.44039 in.)
U/S 0.25 61.745±61.755 mm
(2.43091±2.43130 in.)
EM±82±
ENGINE MECHANICAL Cylinder Block
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Bearing center wall thickness:
Mark º1º 1.994±1.997 mm(0.0785±0.0786 in.)
Mark º2º 1.997±2.000 mm (0.0786±0.0787 in.)
Mark º3º 2.000±2.003 mm (0.0787±0.0789 in.)
Mark º4º 2.003±2.006 mm
(0.0789±0.0790 in.)
Mark º5º 2.006±2.009 mm (0.0790±0.0791 in.)
U/S 0.25 2.114±2.120 mm
(0.0832±0.0835 in.)
Standard sized Bearing Selection Chart
 Crankshaft number mark Cylinder block number mark
 
Crankshaft number mark01234567
011122233 1 1 1 2 2 2 3 3 3 2 1 2 2 2 3 3 3 4 3 2 2 2 3 3 3 4 4 4 2 2 3 3 3 4 4 4
 5 2 3 3 3 4 4 5 5
 6 3 3 3 4 4 5 5 5
 7 3 3 4 4 5 5 5 5
EXAMPLE: Cylinder block º3º, Crankshaft º4º= Use bearing º3º
(k) Completely remove the Plastigage.
7. REMOVE CRANKSHAFT (a) Lift out the crankshaft
(b) Remove the upper bearings and upper thrust washersfrom the cylinder block.
HINT: Arrange the main bearing caps, bearings and thrust
washers in correct order.
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ENGINE MECHANICAL Cylinder BlockEM±83
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INSPECTION AND REPAIR OF
CYLINDER BLOCK
1. CLEAN CYLINDER BLOCK
A. Remove gasket materialUsing a gasket scraper, remove all the gasket material from
the cylinder block surface.
B. Clean cylinder block Using a soft brush and solvent, thoroughly clean the cylinder
block.
2. INSPECT CYLINDER BLOCK SURFACE FOR FLATNESS Using precision straight edge and feeler gauge, measure the
top surfaces of the cylinder block for warpage.
Maximum warpage: 0.07 mm (0.0028 in.)
If warpage is greater than maximum, replace the cylinder
block.
3. INSPECT CYLINDER FOR VERTICAL SCRATCHES Visually check the cylinder for vertical scratches.
If deep scratches are present, replace the cylinder block.
4. INSPECT CYLINDER BORE DIAMETER (a) Using a cylinder gauge, measure the cylinder borediameter at positions A, B and C in the thrust and axial
directions.
Standard diameter: 86.000±86.013 mm
(3.3858±3.3863 in.)
Maximum diameter: 86.02 mm (3.3866 in.)
If the diameter is greater than maximum, replace the cylinder
block.
(b) Difference between measurements A, B and C is greater than taper limit.
Taper limit: 0.01 mm (0.0004 in.)
(c) Difference between the thrust and axial measurementsis greater than out±of±round limit.
Out±of±round limit: 0.02 mm (0.0008 in.)
EM±84±
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5. REMOVE CYLINDER RIDGEIf the wear is less than 0.2 mm (0.008 in.), using a ridge ream-
er, grind the top of the cylinder.
6. INSPECT MAIN BEARING CAP BOLTS Using vernier calipers, measure the minimum diameter of the
compressed thread at the measuring point.
Standard diameter: 9.96±9.97 mm
(0.3921±0.3925 in.)
Minimum diameter: 9.7 mm (0.3819 in.)
If the diameter is less than minimum, replace the bolt.
DISASSEMBLY OF PISTON AND
CONNECTING ROD ASSEMBLIES
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 two compression rings.
(b) Remove the two side rails and oil ring expander by hand. HINT: Arrange the piston rings in correct order only.
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ENGINE MECHANICAL Cylinder BlockEM±85
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3. DISCONNECT CONNECTING ROD FROM PISTON(a) Using a small screwdriver, remove the snap rings.
(b) Gradually heat the piston to about 80
C (176
F).
(c) Using a plastic±faced hammer and brass bar, lightly tap out the piston pin and remove the connecting rod.
HINT:
w The piston and pin are a matched set.
w Arrange the pistons, pins, rings, connecting rods and
bearings in correct order.
EM±86
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INSPECTION OF PISTON AND
CONNECTING ROD ASSEMBLIES
1. CLEAN PISTON(a) Using a gasket scraper, remove the carbon from thepiston top.
(b) Using a groove cleaning tool or broken ring, clean the piston ring grooves.
(c) Using solvent and a brush, thoroughly clean the piston.
NOTICE: Do not use a wire brush.
2. INSPECT PISTON
A. Inspect piston oil clearance (a) Using a micrometer, measure the piston diameter at
right angles to the piston pin center line, 34 mm (1.34 in.)
from the piston head.
Piston diameter: 85.935±85.945 mm
(3.3833±3.3837 in.)
(b) Me a su re th e cylinder bore diameter in the thrust
directions. (See step 4 on page EM±84)
(c) Subtract the piston diameter measurement from the cylinder bore diameter measurement.
Standard oil clearance: 0.055±0.078 mm
(0.0022±0.0031 in.)
Maximum oil clearance: 0.10 mm (0.0039 in.)
If the oil clearance is greater than maximum, replace all the
six pistons. If necessary, replace the cylinder block.
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ENGINE MECHANICAL Cylinder BlockEM±87
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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 piston ring groove.
Ring groove clearance:
No. 1 0.011±0.07 mm (0.0004±0.0028 in.)
No. 2 0.03±0.07 mm (0.0012±0.0028 in.)
If the clearance is not as specified, replace the piston.
C. Inspect piston ring end gap (a) Insert the piston ring into the cylinder bore.
(b) Using a piston, push the piston ring a little beyond thebottom of the ring travel, 130 mm (5.12 in.) from the top
of the cylinder block.
(c) Using a feeler gauge, measure the ring end gap.
Standard ring end gap: No. 1 0.30±0.47 mm (0.0120±0.0188 in.)
No. 2 0.35±0.52 mm (0.0138±0.0208 in.)
Oil (Side rail) 0.13±0.45 mm
(0.0051±0.0177 in.)
Maximum ring end gap: No. 1 1.07 mm (0.0428 in.)
No. 2 1.12 mm (0.0448 in.)
Oil (Side rail) 1.05 mm (0.0420 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 80 5C (176 5F), you should be able to push the piston pin
into the piston pin hole with your thumb.
If the piston pin can be pushed in at room temperature, the
piston and the piston pin must be replaced as a set.
EM±88
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3. INSPECT CONNECTING ROD
A. Inspect connecting rod alignmentUsing a feeler gauge and rod aligner, check the connecting
rod alignment.w Check 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.
w Check 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 ofthe connecting rod bushing.
Bushing inside diameter: 22.005±22.014 mm
(0.8663±0.8667 in.)
(b) Using a micrometer, measure the piston pin diameter.
Piston pin diameter: 21.997±22.006 mm(0.8660±0.8664 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.
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ENGINE MECHANICAL Cylinder BlockEM±89
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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 connectingrod.
(c) Using SST and a press, press in the bushing.
SST 09222±30010
(d) Using a pin hole grinder, bore 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 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 vernier calipers, measure the minimum diameter of the
compressed bolt at the measuring point.
Standard diameter: 8.2±8.3 mm
(0.325±0.327 in.)
Minimum diameter: 8.0 mm (0.315 in.)
If the diameter is less than minimum, replace the connecting
rod bolt.
EM±90
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INSPECTION OF CRANKSHAFT
1. INSPECT CRANKSHAFT FOR RUNOUT(a) Place the crankshaft on V±blocks.
(b) Using a dial indicator, measure the circle runout at thecenter journal.
Maximum circle runout: 0.06 mm (0.0024 in.)
If the circle runout is greater than maximum, replace the
crankshaft.
2. INSPECT MAIN JOURNALS AND CRANK PINS (a) Using a micr ometer, measure the diameter of each main
journal and crank pin.
Main journal diameter: 61.984±62.000 mm
(2.4403±2.4409 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 page EM±77 or EM±80).
(b) Check each main journal and crank pin for taper andout±of±round as shown.
Maximum taper and out±of round: 0.02 mm
(0.0008 in.)
If the taper or out±of±round is greater than maximum, re-
place the crankshaft.
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ENGINE MECHANICAL Cylinder BlockEM±91
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