Lexus SC300 / Lexus SC400. Manual — part 402

(k) Remove the ten bolts, twenty nuts and five main bearing

caps. (See procedure (a) to (c) above)

(l)

Remove the five upper main bearings from the cylinder
block.

HINT: Arrange the main bearing caps, bearings and thrust
washers in correct order.

INSPECTION AND REPAIR OF
CYLINDER BLOCK

1.

CLEAN CYLINDER BLOCK

A.

Remove gasket material
Using a gasket scraper, remove all the gasket material from
the top surfaces of the cylinder block.

B.

Clean cylinder block
Using a soft brush and solvent, thoroughly clean the cylinder
block.
NOTICE: If the cylinder is washed at high temperatures,
the cylinder liner sticks out beyond the cylinder block, so
always wash the cylinder block at temperature of 45

°

or

less.

2.

INSPECT TOP SURFACES OF CYLINDER BLOCK 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.

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ENGINE MECHANICAL

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
HINT: There are three sizes of the standard cylinder bore di-
ameter, marked ”1”, ”2” and ”3” accordingly. The marked is
stamped on the top of the cylinder block.

Using a cylinder gauge, measure the cylinder bore diameter
at positions A, B and C in the thrust and axial directions.

Standard diameter:

Mark ”1” 87.500–87.510 mm

(3.4449–3.4453 in.)

Mark ”2” 87.510–87.520 mm

(3.4453–3.4457 in.)

Mark ”3” 87.520–87.530 mm

(3.4457–3.4461 in.)

Maximum diameter: 87.73 mm (3.4539 in.)

If the diameter is greater than maximum, replace the cylinder
block.

5.

REMOVE CYLINDER RIDGE
If the wear is less than 0.2 mm (0.008 in.), using a ridge ream-
er, grind the top of the cylinder.

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ENGINE MECHANICAL

Cylinder Block

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6.

INSPECT MAIN BEARING CAP STUD BOLTS
Using a vernier caliper, measure the tension portion diameter
of the stud bolt.

Standard diameter: 7.500–7.600 mm

(0.2953–0.2992 in.)

Minimum diameter: 7.40 mm (0.2913 in.)

If the diameter is less than minimum, replace the stud bolt.

7.

IF NECESSARY, REPLACE MAIN BEARING CAP STUD
BOLTS
(a) Using the two main bearing cap nuts, remove the stud

bolt.

(b) Apply

a

light coat of engine oil on the threads and under

the flange of the stud bolt.

(c) Using the two main bearing cap nuts, install and torque

the stud bolt.

Torque: 10 N

⋅

m (100 kgf

⋅

cm, 7 ft

⋅

lbf)

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.

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.

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ENGINE MECHANICAL

Cylinder Block

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.

3.

DISCONNECT CONNECTING ROD FROM PISTON
(a) Using a small screwdriver, pry out the two snap rings.

(b) Gradually heat the piston to approx. 60

°

C (140

°

F).

(c) Using a plastic–face hammer and brass bar, lightly tap

out the piston pin and remove the connecting rod.

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ENGINE MECHANICAL

Cylinder Block

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