Lexus ES300 (1997 year). Manual — part 466

EM0801

EM0281

EM1628

EM2011

EM2538

–

ENGINE MECHANICAL

CYLINDER HEAD

EM–45

782

1997 LEXUS ES300 (RM511U)

(b)

Using vernier calipers, measure the free length of the
valve spring.
Free length: 45.50 mm (1.7913 in.)

If the free length is not as specified, replace the valve spring.

(c)

Using a spring tester, measure the tension of the valve
spring at the specified installed length.
Installed tension:
186 – 206 N (19.0 – 21.0 kgf, 41.9 – 46.3 lbf)
at 33.8 mm (1.331 in.)

If the installed tension is not as specified, replace the valve
spring.

14.

INSPECT CAMSHAFT FOR RUNOUT

(a)

Place the camshaft on V–blocks.

(b)

Using a dial indicator, measure the circle runout at the
center journal.
Maximum circle runout: 0.06 mm (0.0024 in.)

If the circle runout is greater than maximum, replace the cam-
shaft.

15.

INSPECT CAM LOBES

Using a micrometer, measure the cam lobe height.

Standard cam lobe height:
Intake: 42.11 – 42.21 mm (1.6579 – 1.6618 in.)
Exhaust: 41.96 – 42.06 mm (1.6520 – 1.6559 in.)
Minimum cam lobe height:
Intake: 41.96 mm (1.6520 in.)
Exhaust: 41.81 mm (1.6461 in.)

If the cam lobe height is less than minimum, replace the cam-
shaft.
16.

INSPECT CAMSHAFT JOURNALS

Using a micrometer, measure the journal diameter.

Journal diameter:
Intake: 26.949 – 26.965 mm (1.0610 – 1.0616 in.)
Exhaust: 26.959 – 26.975 mm (1.0613 – 1.0620 in.)

If the journal diameter is not as specified, check the oil clear-
ance.

P12401

P13009

Plastigage

P12892

P13004

EM–46

–

ENGINE MECHANICAL

CYLINDER HEAD

783

1997 LEXUS ES300 (RM511U)

17.

INSPECT CAMSHAFT BEARINGS

Check that bearings for flaking and scoring.
If the bearings are damaged, replace the bearing caps and cyl-
inder head as a set.

18.

INSPECT CAMSHAFT JOURNAL OIL CLEARANCE

(a)

Clean the bearing caps and camshaft journals.

(b)

Place the camshafts on the cylinder head.

(c)

Lay a strip of Plastigage across each of the camshaft jour-
nal.

(d)

Install the bearing caps. (See page

EM–52

)

Torque: 16 N·m (160 kgf·cm, 12 ft·lbf)

NOTICE:
Do not turn the camshaft.
(e)

Remove the bearing caps.

(f)

Measure the Plastigage at its widest point.
Standard oil clearance:
Intake: 0.035 – 0.072 mm (0.0014 – 0.0028 in.)
Exhaust: 0.025 – 0.062 mm (0.0010 – 0.0024 in.)
Maximum oil clearance:
Intake: 0.10 mm (0.0039 in.)
Exhaust: 0.09 mm (0.0035 in.)

If the oil clearance is greater than maximum, replace the cam-
shaft. If necessary, replace the bearing caps and cylinder head
as a set.
(g)

Completely remove the Plastigage.

(h)

Remove the camshafts.

P12891

P12960

EM3322

Free Distance

P12685

EM6368

–

ENGINE MECHANICAL

CYLINDER HEAD

EM–47

784

1997 LEXUS ES300 (RM511U)

19.

INSPECT CAMSHAFT THRUST CLEARANCE

(a)

Install the camshafts. (See page

EM–52

)

(b)

Using a dial indicator, measure the thrust clearance while
moving the camshaft back and forth.
Standard thrust clearance:
0.040 – 0.090 mm (0.0016 – 0.0035 in.)
Maximum thrust clearance: 0.12 mm (0.0047 in.)

If the thrust clearance is greater than maximum, replace the
camshaft. If necessary, replace the bearing caps and cylinder
head as a set.
(c)

Remove the camshafts.

20.

INSPECT CAMSHAFT GEAR BACKLASH

(a)

Install the camshafts without installing the exhaust cam-
shaft sub–gear. (See page

EM–52

)

(b)

Using a dial indicator, measure the backlash.
Standard backlash:
0.020 – 0.200 mm (0.0008 – 0.0079 in.)
Maximum backlash: 0.30 mm (0.0188 in.)

If the backlash is greater then maximum, replace the cam-
shafts.
(c)

Remove the camshafts.

21.

INSPECT CAMSHAFT GEAR SPRING

Using vernier calipers, measure the free distance between the
spring ends.

Free distance: 18.2 – 18.8 mm (0.712 – 0.740 in.)

If the free distance is not as specified, replace the gear spring.

22.

INSPECT VALVE LIFTERS AND LIFTER BORES

(a)

Using a caliper gauge, measure the lifter bore diameter
of the cylinder head.
Lifter bore diameter:
31.000 – 31.018 mm (1.2205 – 1.2212 in.)

(b)

Using a micrometer, measure the lifter diameter.
Lifter diameter:
30.966 – 30.976 mm (1.2191 – 1.2195 in.)

(c)

Subtract the lifter diameter measurement from the lifter
bore diameter measurement.
Standard oil clearance:
0.024 – 0.050 mm (0.0009 – 0.0020 in.)
Maximum oil clearance: 0.07 mm (0.0028 in.)

If the oil clearance is greater than maximum, replace the lifter.
If necessary, replace the cylinder head.

P12400

Z09167

Cylinder Head Side

Air Intake Chamber Side

Z09168

RH Side

LH Side

EM–48

–

ENGINE MECHANICAL

CYLINDER HEAD

785

1997 LEXUS ES300 (RM511U)

23.

INSPECT AIR INTAKE CHAMBER

Using a precision straight edge and feeler gauge, measure the
surface contacting the intake manifold for warpage.

Maximum warpage: 0.10 mm (0.0039 in.)

If warpage is greater than maximum, replace the chamber.

24.

INSPECT INTAKE MANIFOLD

Using a precision straight edge and feeler gauge, measure the
surface contacting the cylinder head and air intake chamber for
warpage.

Maximum warpage:
Air intake chamber side: 0.15 mm (0.0059 in.)
Cylinder head side: 0.08 mm (0.0031 in.)

If warpage is greater than maximum, replace the manifold.

25.

INSPECT EXHAUST MANIFOLDS

Using a precision straight edge and feeler gauge, measure the
surface contacting the cylinder head for warpage.

Maximum warpage: 0.50 mm (0.0196 in.)

If warpage is greater than maximum, replace the manifold.