Lexus SC300 / Lexus SC400. Manual — part 387

B.

Inspect piston ring groove clearance
Using a feeler gauge, measure the clearance between new
piston ring and the wall of the ring groove

Ring groove clearance:

No.1

0.020 – 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.1

0.250 – 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.1

1.05 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

°

C (140

°

F), 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 MECHANICAL

EG–171

3.

INSPECT CONNECTING ROD

A.

Inspect connecting rod alignment
Using a rod aligner and feeler gauge, check the connecting
rod alignment.

•

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.

•

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 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 the

bushing 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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1UZ–FE ENGINE

ENGINE MECHANICAL

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 connecting rod.
(c) Using SST and a press, press out the bushing

SST 09222–30010

(d) Using a pin hole grinder, hone 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 normal 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 a vernier caliper, measure the tension portion of of the
connecting rod bolt.

Standard diameter:

7.200 – 7.300 mm (0.2835 – 0.2874 in.)

Maximum diameter:

7.00 mm (0.2756 in.)

HINT: If the tension portion diameter is less than minimum,
replace the connecting rod bolt.

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1UZ–FE ENGINE

ENGINE MECHANICAL

EG–173

CRANKSHAFT INSPECTION

EG0BY–0D

1.

INSPECT CRANKSHAFT FOR CIRCLE RUNOUT

(a) Place the crankshaft on V–blocks.
(b) Using a dial indicator, measure the circle runout at the center

journal.

Maximum circle runout:

0.08 mm (0.0031 in.)

If the circle runout is greater than maximum, replace the
crankshaft.

2.

INSPECT MAIN JOURNALS AND CRANK PINS

(a) Using a micrometer, measure the diameter of each main

journal and crank pin.

Main journal diameter:

66.988 – 67.000 mm (2.6373 – 2.6378 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 steps 3 or 6 on page

EG–156

or 160). If necessary, re-

place the crankshaft.

(b) Check each main journal and crank pin for taper and

out–of–round as shown.

Maximum taper and out–of–round:

0.02 mm (0.0008 in.)

If the taper and out–of–round is greater than maximum, re-
place the crankshaft.

EG–174

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1UZ–FE ENGINE

ENGINE MECHANICAL