Lexus RX300 (MCU15). Service manual - part 441

A05704

EM2011

EM2538

A05236

A05239

Plastigage

EM–48

–

ENGINE MECHANICAL

CYLINDER HEAD

LEXUS RX300   (RM785E)

13.

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.

14.

INSPECT CAM LOBES

Using a micrometer, measure the cam lobe height.

Standard cam lobe height: 
Intake: 42.932 – 43.032 mm (1.6902 – 1.6942 in.) 
Exhaust: 42.764– 42.864 mm (1.6836 – 1.6876 in.)
Minimum cam lobe height: 
Intake: 42.78 mm (1.6842 in.) 
Exhaust: 42.61 mm (1.6776 in.)

If the cam lobe height is less than minimum, replace the cam-
shaft.
15.

INSPECT CAMSHAFT JOURNALS

Using a micrometer, measure the journal diameter.

Journal diameter: 
Intake: 26.959 – 26.975 mm (1.0614 – 1.0620 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.

16.

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.

17.

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.

A05237

A05240

A05238

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ENGINE MECHANICAL

CYLINDER HEAD

EM–49

LEXUS RX300   (RM785E)

(d)

Install the bearing caps. (See page EM–60)
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.

18.

INSPECT CAMSHAFT THRUST CLEARANCE

(a)

Install the camshafts. (See page EM–60)

(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.

A05241

A05739

A05705

EM–50

–

ENGINE MECHANICAL

CYLINDER HEAD

LEXUS RX300   (RM785E)

19.

INSPECT CAMSHAFT GEAR BACKLASH

(a)

Install the camshafts without installing the exhaust cam-
shaft sub–gear. (See page EM–60)

(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.

20.

INSPECT CAMSHAFT TIMING GEAR (VVT–i)

(a)

Mount the hexagon wrench head portion of the camshaft
in a vise.

(b)

Check that VVT–i will not turn.

(c)

Cover the port except the port on the advance angle side
(nearest to the convex portion) shown in the illustration
with the vinyl tape.

(d)

Using the air gun, apply about 100 kPa (1 kgf/cm

3

, 14 psi)

of air pressure to the port on the advance side shown in
the illustration.

NOTICE:
When the oil is splashed, wipe it off with a shop lug and the
likes.
HINT:
Perform this in order to release the lock pin for the maximum
delay angle locking.

Standard: Must turn

HINT:
Depending on the air pressure, VVT–i will turn to the advance
angle side without applying force by hand. Also, under the
condition that the pressure can be hardly applied because of
the air leakage from the port, there may be the case that the lock
pin could be hardly released.
(e)

Under the condition of (d), turn VVT–i to the advance
angle side (the white arrow marked direction in the il-
lustration) with your hand.

(f)

Except the position where the lock pin meets at the maxi-
mum delay angle, let VVT–i turn back and forth and check
the movable range and that there is no disturbance.
Standard: Movable smoothly in the range about 30°

(g)

Turn VVT–i with your hand and lock it at the maximum
delay angle position.

EM3322

Free Distance

P12685

EM6368

P12400

–

ENGINE MECHANICAL

CYLINDER HEAD

EM–51

LEXUS RX300   (RM785E)

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.
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.