Lexus SC300 / Lexus SC400. Service manual — part 584

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 OIL

CLEARANCE
(a) Using a punch or numbering stamp, place the

matchmarks 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 Block

EM–135

(d) Clean the crank pin and bearings.
(e) Check the crank pin and bearing for pitting and

scratches.

If the crank pin or bearing are damaged, replace the bear-
ings. If necessary, replace the crankshaft.

(f) Lay a strip of Plastigage across the crank pin.

(g) Install the connecting rod cap with the two bolts.

(See step 6 on pages

EM–159

and 160)

Torque: 1st 25 N

⋅

m (250 kgf

⋅

cm, 18 ft

⋅

lbf)

2nd Turn 90

°

NOTICE: Do not turn the crankshaft.

(h) Remove the two bolts, connecting rod cap and lower

bearing. (See procedure (b) and (c) above)

(i)

Measure the Plastigage at 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.

EM–136

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ENGINE MECHANICAL

Cylinder Block

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 connecting rod cap and crank-
shaft, then selecting the bearing with the same number as the
total. There are six sizes of standard bearings, marked ”2”,
”3”, ”4”, ”5”, ”6” and ”7” accordingly.

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Connecting rod cap

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2

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3

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2

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3

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4

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Crakshaft

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2

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1

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3

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2

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1

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3

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2

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1

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3

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2

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Use bearing

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7

EXAMPLE: Connecting rod cap ”3” + Crankshaft ”1”

= Total number 4 (Use bearing ”4”)

(Reference)

Connecting rod big end inside diameter:

Mark ”1” 55.000–55.006 mm

(2.1654–2.1656 in.)

Mark ”2” 55.006–55.012 mm

(2.1656–2.1658 in.)

Mark ”3” 55.012–55.018 mm

(2.1658–2.1661 in.)

Mark ”4” 55.018–55.024 mm

(2.1661–2.1663 in.)

Crankshaft crank pin diameter:

Mark ”1” 51.994–52.000 mm

(2.0470–2.0472 in.)

Mark ”2” 51.988–51.994 mm

(2.0468–2.0470 in.)

Mark ”3” 51.982–51.988 mm

(2.0465–2.0468 in.)

Standard sized bearing center wall thickness:

Mark ”2” 1.484–1.487 mm

(0.0584–0.0585 in.)

Mark ”3” 1.487–1.490 mm

(0.0585–0.0587 in.)

Mark ”4” 1.490–1.493 mm

(0.0587–0.0588 in.)

Mark ”5” 1.493–1.496 mm

(0.0588–0.0589 in.)

Mark ”6” 1.496–1.499 mm

(0.0589–0.0590 in.)

Mark ”7” 1.499–1.502 mm

(0.0590–0.0591 in.)

(j)

Completely remove the Plastigage.

4. REMOVE PISTON AND CONNECTING ROD

ASSEMBLIES
(a) Using

a

ridge reamer, remove all the carbon from the top

of the cylinder.

(b) Push the piston, connecting rod assembly and upper

bearing through the top of the cylinder block.

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ENGINE MECHANICAL

Cylinder Block

EM–137

HINT:

•

Keep the bearings, connecting rod and cap together.

•

Arrange the piston and connecting rod assemblies in
correct order.

5.

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