Lexus ES300 (1997 year). Manual — part 465

P12754

Z00052

P12688

80 – 100

°

C

P12803

SST

–

ENGINE MECHANICAL

CYLINDER HEAD

EM–41

778

1997 LEXUS ES300 (RM511U)

9.

INSPECT VALVE STEMS AND GUIDE BUSHINGS

(a)

Using a caliper gauge, measure the inside diameter of the
guide bushing.
Bushing inside diameter:
5.510 – 5.530 mm (0.2169 – 0.2177 in.)

(b)

Using a micrometer, measure the diameter of the valve
stem.
Valve stem diameter:
Intake: 5.470 – 5.485 mm (0.2154 – 0.2159 in.)
Exhaust: 5.465 – 5.480 mm (0.2152 – 0.2157 in.)

(c)

Subtract the valve stem diameter measurement from the
guide bushing guide bushing inside diameter measure-
ment.
Standard oil clearance:
Intake: 0.025 – 0.060 mm (0.0010 – 0.0024 in.)
Exhaust: 0.030 – 0.065 mm (0.0012 – 0.0026 in.)
Maximum oil clearance:
Intake: 0.08 mm (0.0031 in.)
Exhaust: 0.10 mm (0.0039 in.)

If the clearance is greater than maximum, replace the valve and
guide bushing.

10.

IF NECESSARY, REPLACE VALVE GUIDE
BUSHINGS

(a)

Gradually heat the cylinder head to 80 – 100

°

C (176 –

212

°

F).

(b)

Using SST and a hammer, tap out the guide bushing.
SST

09201–01055, 09950–70010 (09951–07100)

P12956

Bushing bore diameter

mm (in.)

10.295 – 10.313

(0.4053 – 0.4060)

10.345 – 10.363

(0.4073 – 0.4080)

Bushing size

Use STD

Use O/S 0.05

Both intake and exhaust

P11510

Intake

Exhaust

34.5 mm

(1.358 in.)

40.5 mm

(1.594 in.)

P12802

SST

Z09124

EM–42

–

ENGINE MECHANICAL

CYLINDER HEAD

779

1997 LEXUS ES300 (RM511U)

(c)

Using a caliper gauge, measure the bushing bore diame-
ter of the cylinder head.

(d)

Select a new guide bushing (STD or O/S 0.05).

If the bushing bore diameter of the cylinder head is greater than
10.313 mm (0.4060 in.), machine the bushing bore to the fol-
lowing dimension:

10.345 – 10.363 mm (0.4073 – 0.4080 in.)

If the bushing bore diameter of the cylinder head is greater than
10.363 mm (0.4080 in.), replace the cylinder head.

HINT:
Different bushings are used for the intake and exhaust.
(e)

Gradually heat the cylinder head to 80 – 100

°

C (176 –

212

°

F).

(f)

Using SST and a hammer, tap in a new guide bushing to
the specified protrusion height.
SST

09201–01055, 09950–70010 (09951–07100)

Protrusion height:
Intake: 11.5 – 11.3 mm (0.437 – 0.453 in.)
Exhaust: 8.9 – 9.3 mm (0.350 – 0.366 in.)

(g)

Using a sharp 5.5 mm reamer, ream the guide bushing to
obtain the standard specified clearance (See step 9
above) between the guide bushing and valve stem.

Z00054

44.5

°

EM0181

Margin Thickness

EM2534

Overall Length

EM0255

P12704

–

ENGINE MECHANICAL

CYLINDER HEAD

EM–43

780

1997 LEXUS ES300 (RM511U)

11.

INSPECT AND GRIND VALVES

(a)

Grind the valve enough to remove pits and carbon.

(b)

Check that the valve is ground to the correct valve face
angle.
Valve face angle: 44.5

°

(c)

Check the valve head margin thickness.
Standard margin thickness: 1.0 mm (0.039 in.)
Minimum margin thickness: 0.5 mm (0.020 in.)

If the margin thickness is less than minimum, replace the valve.

(d)

Check the valve overall length.
Standard overall length:
Intake: 95.45 mm (3.5779 in.)
Exhaust: 95.40 mm (3.7559 in.)
Minimum overall length:
Intake: 94.95 mm (3.7382 in.)
Exhaust: 94.90 mm (3.7362 in.)

If the overall length is less than minimum, replace the valve.

(e)

Check the surface of the valve stem tip for wear.

If the valve stem tip is worn, resurface the tip with a grinder or
replace the valve.
NOTICE:
Do not grind off more than minimum.

12.

INSPECT AND CLEAN VALVE SEATS

(a)

Using a 45

°

carbide cutter, resurface the valve seats.

Remove only enough metal to clean the seats.

P12729

Width

Z03988

45

°

30

°

1.0 – 1.4 mm

Z03989

45

°

1.0 – 1.4 mm

75

°

P12705

EM0988

Deviation

EM–44

–

ENGINE MECHANICAL

CYLINDER HEAD

781

1997 LEXUS ES300 (RM511U)

(b)

Check the valve seating position.
Apply a light coat of prussian blue (or white lead) to the
valve face. Lightly press the valve against the seat. Do not
rotate valve.

(c)

Check the valve face and seat for the following:

If blue appears 360

°

around the face, the valve is

concentric. If not, replace the valve.

If blue appears 360

°

around the valve seat, the

guide and face are concentric. If not, resurface the
seat.

Check that the seat contact is in the middle of the
valve face with the following width:

Contacting width: 1.0 – 1.4 mm (0.039 – 0.055 in.)

If not, correct the valve seats as follows:

If the seating is too high on the valve face, use
30

°

and 45

°

cutters to correct the seat.

If the seating is too low on the valve face, use
75

°

and 45

°

cutters to correct the seat.

(d)

Hand–lap the valve and valve seat with an abrasive com-
pound.

(e)

After hand–lapping, clean the valve and valve seat.

13.

INSPECT VALVE SPRINGS

(a)

Using a steel square, measure the deviation of the valve
spring.
Maximum deviation: 2.0 mm (0.079 in.)

If the deviation is greater than maximum, replace the valve
spring.