Lexus SC300 / Lexus SC400. Manual — part 405

ASSEMBLY OF PISTON AND
CONNECTING ROD ASSEMBLIES

1.

ASSEMBLE PISTON AND CONNECTING ROD
(a) Using

a

small screwdriver, install a new snap ring on one

side of the piston pin hole.

(b) Gradually heat the piston to about 60

°

C (140

°

F).

(c) Position the piston front mark with respect to the outside

mark on the connecting rod as shown in the diagram.

NOTICE: The installation direction of the piston and con-
necting rod are different for the RH and LH banks. The RH
piston is marked with ”R”, the LH piston with ”L”.
(d) Align the piston pin holes 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 side of the piston pin hole.

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ENGINE MECHANICAL

Cylinder Block

2. INSTALL

PISTON

RINGS

(a) Install the oil ring expander and two side rails by hand.

(b) Using a piston ring expander, install the two

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 piston ring ends.

3. INSTALL

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.

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ENGINE MECHANICAL

Cylinder Block

EM–155

ASSEMBLY OF CYLINDER BLOCK

(See Components on page

EM–131

)

HINT:

•

Thoroughly clean all parts to be assembled.

•

Before installing the parts, apply new engine oil to all
sliding and rotating surfaces.

•

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

1.

INSTALL MAIN BEARINGS
HINT:

•

Main bearings come in widths of 19.5 mm (0.768 in.) and
22.5 mm (0.886 in.). Install the 22.5 mm (0.886 in.)
bearings in the No.1 and No.5 cylinder block journal
positions with the main bearing caps. Install the 19.5
mm (0.768 in.) bearings in the other positions.

•

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

(a) Align

the

bearing

claw

with

the

claw

groove of

the

cylinder block, and push in the five upper bearings.

(b) Align the bearing claw with the claw groove of the main

bearing cap, and push in the five lower bearings.

HINT: A number is marked on each main bearing cap indicat-
ing the installation position.

2.

INSTALL UPPER THRUST WASHERS
Install the two thrust washers under the No.3 journal position
of the block with the oil grooves facing outward.

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ENGINE MECHANICAL

Cylinder Block

3.

PLACE CRANKSHAFT ON CYLINDER BLOCK

4. INSTALL MAIN BEARING CAP AND LOWER THRUST

WASHERS

A.

Place main bearing cap and lower thrust washers on cyl-
inder block
(a) Install the two thrust washers on the No.3 main bearing

cap with the grooves facing outward.

(b) Install the main bearing caps in their proper location.

(c) Place the five bearing caps in position on cylinder block.
HINT: Place the bearing caps level and let them return to their
original position by their own weight.
NOTICE: Do not install the main bearing cap by tapping
it.

B.

Install main bearing cap nuts
HINT:

•

The main bearing cap nuts are tightened in two
progressive steps (steps (b) and (d)).

•

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

(a) Apply

a

light coat of engine oil on the threads and under

the nuts of the main bearing caps.

(b) Install

and uniformly tighten the twenty main bearing cap

nuts in several passes in the sequence shown.

Torque: 27 N

⋅

m (275 kgf

⋅

cm, 20 ft

⋅

lbf)

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

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ENGINE MECHANICAL

Cylinder Block

EM–157