Lexus SC300 / Lexus SC400. Manual - part 401

HINT:

•

Keep the bearings, connecting rod and cap together.

•

Arrange the piston and connecting rod assemblies in
correct order.

CHECK CRANKSHAFT THRUST CLEARANCE
Using a dial indicator, 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.)

6. REMOVE MAIN BEARING CAP AND CHECK OIL

CLEARANCE
(a) Remove the ten main bearing cap bolts.

(b) Uniformly loosen and remove the twenty main bearing

cap nuts in several passes in the sequence shown.

EM–138

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ENGINE MECHANICAL

Cylinder Block

and remove the five main bearing cap, lower main
bearings and two lower thrust washers (No.3 main
bearing cap only).

NOTICE: Be careful not to damage the cylinder block.
HINT:

•

Keep the lower main bearing and main bearing cap
together.

•

Arrange the main bearing caps and lower thrust
washers in correct order.

(d) Lift out the crankshaft.
(e) Remove the two upper thrust washers.
HINT:

•

Arrange the upper thrust washers in correct order.

•

Keep the upper main bearings together with the cylinder
block.

(f) Clean each main journal and bearing.
(g) Check each main journal and bearing for pitting and

scratches.

If the journal or bearing are damaged, replace the bearings.
If necessary, replace the crankshaft.

(h) Install the five main bearing caps with the twenty nuts

and ten bolts. Do not install the crankshaft.
(See step 4 on pages

EM–157

and 158)

Torque:

Nut 1st 27 N

⋅

m (275 kgf

⋅

cm, 20 ft

⋅

lbf)

2nd Turn 90

Bolt 49 N

⋅

m (500 kgf

⋅

cm, 36 ft

⋅

lbf)

(i)

Using a cylinder gauge, measure the inside diameter of
the main bearing.

Bearing inside diameter: 67.026–67.033 mm

(2.6388–2.6391 in.)

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ENGINE MECHANICAL

Cylinder Block

EM–139

(j)

Using a micrometer, measure the diameter of the main
journal.

Main journal diameter: 66.988–67.000 mm

(2.6373–2.6378 in.)

(k) Subtract the main journal diameter measurement from

the main bearing inside diameter measurement.

Standard oil 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.

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 ”1”, ”2”, ”3”,
”4” and ”5” accordingly.

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Total number ” ”: Number mark

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Cylinder block (A)

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0–5

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6–11

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12–17

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18–23

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24–28

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Crankshaft (B) =

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Use bearing

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”2”

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”3”

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”4”

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”5”

EXAMPLE: Cylinder block ”06” (A)

+ Crankshaft ”08” (B)
= Total number 14 (Use bearing ”3”)

(Reference)

Cylinder block main journal bore diameter (A):

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.)

EM–140

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ENGINE MECHANICAL

Cylinder Block

Crankshaft main journal diameter (B):

Mark ”00” 67.000 mm (2.6378 in.)

Mark ”01” 66.999 mm (2.6378 in.)

Mark ”02” 66.998 mm (2.6377 in.)

Mark ”03” 66.997 mm (2.6377 in.)

Mark ”04” 66.996 mm (2.6376 in.)

Mark ”05” 66.995 mm (2.6376 in.)

Mark ”06” 66.994 mm (2.6376 in.)

Mark ”07” 66.993 mm (2.6375 in.)

Mark ”08” 66.992 mm (2.6375 in.)

Mark ”09” 66.991 mm (2.6374 in.)

Mark ”10” 66.990 mm (2.6374 in.)

Mark ”11” 66.989 mm (2.6374 in.)

Mark ”12” 66.988 mm (2.6373 in.)

Standard sized bearing center wall thickness:

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.)

Standard sized Bearing Selection Chart

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Crankshaft

number mark

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Cylinder block number mark

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number mark

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EXAMPLE: Cylinder block ”06”, Crankshaft ”08” = Use
bearing ”3”

–

ENGINE MECHANICAL

Cylinder Block

EM–141

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