Lexus ES300 (2002 year). Service manual - part 127

ENGINE – 1MZ-FE ENGINE

EG-7

208EG63

60



Water pump Swirl Chamber

Knock Sensor Bosses

36.6 mm

105.5 mm

Crankshaft Bearing Cap

Sela Washer

Plastic Region Tightening Bolts

View of Top Side

198EG38

187EG10

4. Cylinder Block

 The cylinder block has a bank angle of 60, a bank offset of 36.6 mm (1.44 in.) and a bore pitch of 105.5

mm (4.15 in.), resulting in a compact block.

 Lightweight aluminum alloy is used for the cylinder block.

 A thin cast-iron liner is press- fit inside the cylinder to ensure an added reliability. This liner is thin, so that

boring is not possible.

 A water pump swirl chamber and an inlet passage to the pump are provided in the V-bank to help make

the engine compact.

 Knock sensor bosses are provided at 2 locations in V-bank.

 The crankshaft bearing caps are tightened using 4 plastic- region bolts for each journal. In addition, each

cap is tightened laterally to improve its reliability.

ENGINE – 1MZ-FE ENGINE

EG-8

208EG105

Resin Coating

for Right Bank

208EG106

Knock Pin

Plastic Region
Tightening Bolt

5. Piston

 The piston is made of aluminum alloy and skirt area is made compact and lightweight.

 The piston skirt has been coated with resin to reduce the friction loss.

 Full floating type piston pins are used.

 Each of the pistons is made specifically for the right or left bank.

6. Connecting Rod

 Connecting rods that have been forged for high

strength are used for weight reduction.

 An aluminum bearing with overlay is used for

the connecting rod bearings.

 Plastic region tightening bolts are used.

 Knock pins are used at the mating surfaces of

the bearing caps of the connecting rod to mini-
mize the shifting of the bearing caps during as-
sembly.

ENGINE – 1MZ-FE ENGINE

EG-9

208EG72

Engine
Front

Roll-Finished

No.1 Journal

Balance Weight

No.4 Journal

187EG14

Engine
Front

Cast Iron

Steel

Aluminum

Torsional
Damper Rubber

7. Crankshaft

 The crankshaft is made of forged steel and has 4 journals and 9 balance weights.

 All pin and journal fillets are roll-finished to maintain adequate strength.

 The crankshaft bearings for the No.1 and No.4 journals are made wider to decrease noise and vibration,

and those for the No.2 and No.3 journals are made narrower friction.

8. Crankshaft Pulley

 The crankshaft pulley hub is made of aluminum

to reduce weight and vibration.

 The rigidity of the torsional damper rubber has

been optimized to reduce noise.

ENGINE – 1MZ-FE ENGINE

EG-16

208EG119

Water Pump

Water Outlet

Bypass Passage

Intake Manifold

To Heater

Front Heater

From Radiator

To Radiator

Thermostat

Heater

Heater Valve

Throttle Body

Thermostat

Cylinder Block

Bypass Passage

Radiator

Water
Pump

187EG25

COOLING SYSTEM

 The cooling system is a pressurized, forced-circulation type.
 A thermostat having a bypass valve is located on the water pump inlet side of the cooling circuit.