Lexus RX300 (MCU15). Service manual — part 456

EM0KP–03

A05260

P12417

60

°C

A05261

Front Mark
(2 Cavities)

Front Mark
(Mold Mark)

RH piston:

LH piston:

Front Mark
(1 Cavity)

Front Mark
(Mold Mark)

EM–108

–

ENGINE MECHANICAL

CYLINDER BLOCK

LEXUS RX300 (RM785E)

REASSEMBLY

HINT:

S

Thoroughly clean all parts to be assembled.

S

Before installing the parts, apply new engine oil to all slid-
ing and rotating surfaces.

S

Replace all gaskets, O–rings and oil seals with new parts.

1.

ASSEMBLE PISTON AND CONNECTING ROD

(a)

Using a small screwdriver, install a new snap ring at one
end of the piston pin hole.

HINT:
Be sure that end gap of the snap ring is not aligned with the pin
hole cutout portion of the piston.

(b)

Gradually heat the piston to about 60

°C (140°F).

(c)

Coat the piston pin with engine oil.

(d)

Align the front marks of the piston and connecting rod,
and push in the piston pin with your thumb.

(e)

Using a small screwdriver, install a new snap ring on the
other end of the piston pin hole.

HINT:
Be sure that end gap of the snap ring is not aligned with the pin
hole cutout portion of the piston.

Z09179

Cord Mark

No. 1

No. 2

Cord Mark

A05262

RH piston:

Lower Side Rail

No. 2
Compression

Front Mark

Expander

Upper Side Rail

No. 1
Compression

Lower Side Rail

Upper Side Rail

LH piston:

No. 2
Compression

Expander

No. 1
Compression

Front Mark

P12402

Z09177

No. 1 and No. 4

Upper

Lower

22.4 mm

19.0 mm

No. 2 and No. 3

–

ENGINE MECHANICAL

CYLINDER BLOCK

EM–109

LEXUS RX300 (RM785E)

2.

INSTALL PISTON RINGS

(a)

Install the oil ring expander and 2 side rails by hand.

(b)

Using a piston ring expander, install the 2 compression
rings with the code mark facing upward.
Code mark:
No. 1: 1R or T
No. 2: 2R or 2T

(c)

Position the piston rings so that the ring ends are as
shown.

NOTICE:
Do not align the ring ends.

3.

INSTALL CONNECTING ROD BEARINGS

(a)

Align the bearing claw with the groove of the connecting
rod or connecting cap.

(b)

Install the bearings in the connecting rod and connecting
rod cap.

4.

INSTALL MAIN BEARINGS

HINT:

S

Main bearings come in widths of 19.0 mm (0.748 in.) and
22.4 mm (0.882 in.). Install the 22.4 mm (0.882 in.) bear-
ings in the No. 1 and No. 4 cylinder block journal positions
with the main bearing cap. Install the 19.0 mm (0.748 in.)
bearings in the No. 2 and No. 3 positions.

S

Upper bearings have an oil groove and oil holes; lower
bearings do not.

P12599

A05263

Mark
1, 2, 3 or 4

P12600

P12495

A05264

EM–110

–

ENGINE MECHANICAL

CYLINDER BLOCK

LEXUS RX300 (RM785E)

(a)

Align the bearing claw with the claw groove of the cylinder
block, and push in the 4 upper bearings.

NOTICE:
Install the bearing with the oil hole in the cylinder block.

(b)

Align the bearing claw with the claw groove of the main
bearing cap, and push in the 4 lower bearings.

HINT:
A number is marked on each main bearing cap to indicate the
installation position.

5.

INSTALL UPPER THRUST WASHERS

Install the 2 thrust washers under the No.2 journal position of
the cylinder block with the oil grooves facing outward.

6.

PLACE CRANKSHAFT ON CYLINDER BLOCK

7.

PLACE MAIN BEARING CAPS AND LOWER THRUST
WASHERS ON CYLINDER BLOCK

(a)

Install the 2 thrust washers on the No.2 bearing cap with
the grooves facing outward.

A05265

A05266

Less than 6 mm

A05267

P12753

8

7

6

1

5

2

3

4

9

10

13

14

15

16

11

12

4

7

P25741

Painted Mark

Front

90

°

90

°

–

ENGINE MECHANICAL

CYLINDER BLOCK

EM–111

LEXUS RX300 (RM785E)

(b)

Temporarily place the 4 main bearing caps level and let
them in their proper locations.

(c)

Apply a light coat of engine oil on the threads and under
the main bearing cap bolts for the 12 pointed head.

(d)

Temporarily install the 8 main bearing cap bolts to the in-
side positions.

(e)

Insert the main bearing cap with your hand until the clear-
ance between the main bearing cap and the cylinder
block will become less than 6 mm (0.23 in.) by making the
2 internal main bearing cap bolts as a guide.

(f)

Using a plastic–faced hammer, lightly tap the bearing cap
to ensure a proper fit.

8.

INSTALL 12 POINTED HEAD MAIN BEARING CAP
BOLTS

HINT:

S

The main bearing cap bolts are tightened in 2 progressive
steps (steps (b) and (d)).

S

If any of the main bearing cap bolts is broken or deformed,
replace it.

(a)

Apply a light coat of engine oil on the threads and under
the main bearing cap bolts.

(b)

Install and uniformly tighten the 16 main bearing cap bolts
in several passes, in the sequence shown.
Torque: 22 N·m (225 kgf·cm, 16 ft·lbf)

If any of the main bearing cap bolts does not meet the torque
specification, replace the main bearing cap bolt.

(c)

Mark the front of the main bearing cap bolts with paint.

(d)

Retighten the main bearing cap bolts by 90

° in the numer-

ical order shown.

(e)

Check that the painted mark is now at a 90

° angle to the

front.