engine LEXUS SC400 1991 Service Repair Manual

(b) Install the EGR valve with the two nuts.
Torque: 18 NVm (185 kgf Vcm, 13 ft Vlbf)
(c) Connect the following hoses:
(1) Water by±pass hose (from ISC valve) to the EGR valve
(2) Water by±pass hose (from rear water by±pass joint) to the EGR valve
8. RECONNECT EGR VALVE CONNECTOR
9. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
10. REFILL WITH ENGINE COOLANT (See page CO±7)
INSPECTION OF EGR VALVE
(Exc. USA Spec.)
1. DRAIN ENGINE COOLANT (See page CO±6)
2. REMOVE EGR VALVE (a) Disconnect the following hoses:(1) Vacuum hose (from VSV) from EGR valve
(2) Vacuum hose (from VSV) from EGR vacuum
modulator
(3) Vacuum hose (from EGR vacuum modulator) f rom EGR valve
(4) Water by±pass hose (from ISC valve) from the
EGR valve
(5) Water by±pass hose (from rear water by±pass joint) from the EGR valve
(b) Disconnect the vacuum modulator bracket from the
EGR valve.
(c) Remove the two nuts, EGR valve and gasket.
EC±24
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) System
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3. INSPECT EGR VALVECheck for sticking and heavy carbon deposits.
If a problem is found, replace the EGR valve assembly.
4. REINSTALL EGR VALVE (a) Place a new gasket on the EGR valve adaptor.
NOTICE:
w Do not touch the adaptor and EGR valve surfaces of the
gasket with your hand.
w Align the port holes of the gasket and adaptor.
Be careful of the installation direction.
(b) Install the EGR valve with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(c) Install the vacuum modulator bracket to the EGR valve.
(d) Connect the following hoses:
(1) Vacuum hose (from VSV) to EGR valve
(2) Vacuum hose (from VSV) to EGR vacuum modula- tor
(3) Vacuum hose (from EGR vacuum modulator) to EGR valve
(4) Water by±pass hose (from ISC valve) to the EGR
valve
(5) Water by±pass hose (from rear water by±pass joint) to the EGR valve
5. REFILL WITH ENGINE COOLANT (See page CO±7)
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±25
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ENGINE MECHANICAL
NOTE: The specification descriptions ºUSA Spec.º and
º Exc. USA Spec. º used in this section indicate the following
specifications.
USA Spec .: USA (50 States) Specifications.
Exc. USA Spec .: USA (except California) and Canadian
Specifications.
EM±1
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DESCRIPTION
The 1 UZ±FE engine is an V±8 4.0 liter DOHC 32 valve engine.
OPERATION
EM±2±
ENGINE MECHANICAL Description, Operation
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DESCRIPTION
The 1 UZ±FE engine is an V±8 4.0 liter DOHC 32 valve engine.
OPERATION
EM±2±
ENGINE MECHANICAL Description, Operation
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±
ENGINE MECHANICAL OperationEM±3
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The 1 UZ±FE engine has 8±cylinders in a V±arrangement at a bank an\
gle of 905. From the front of the RH
bank cylinders are numbered 2±4±6±8, and from the front of the LH b\
ank cylinders are numbered 1 ±3±5±7.
The crankshaft is supported by 5 bearings specified by the inside of the cr\
ankcase. These bearings are made
of a copper and lead alloy. The crankshaft is integrated with 8 weights which are cast along with it\
for balancing. Oil holes are built
into the center of the crankshaft for supplying oil to the connecting ro\
ds, pistons and other components. The ignition order is 1±8±4±3±6±5±7±2. The cylinder\
head is made of aluminum alloy, with a cross flow
type intake and exhaust layout and with pent±roof type combustion chambers. The spark plugs are loca\
ted in
the center of the combustion chambers.
At the front and rear of the intake manifold, a water passage has been p\
rovided which connects the RH
and LH cylinder heads. Exhaust and intake valves are equipped with irregular pitch springs made\
of special valve spring carbon
steel which are capable of following no matter what the engine speed.
The RH and LH intake camshafts are driven by a single timing belt, and a ge\
ar on the intake camshaft en-
gages with a gear on the exhaust camshaft to drive it. The camshaft jour\
nal is supported at 5 (intake) or 4 (ex-
haust) places between the valve lifters of each cylinder and on the front end of the cylinder \
head. Lubrication
of the cam journal gear is accomplished by oil being supplied through the \
oiler port in the center of the camshaft. Adjustment of the valve clearance is done by means of an outer shim type\
system, in which valve adjusting
shims are located above the valve lifters. This permits replacement of the sh\
ims without removal of the cam-
shafts. Pistons are made of high temperature±resistant aluminum alloy, and a depression is built into the piston
head to prevent interference with valves.
Piston pins are the full±floating type, with the pins fastened to neither the piston boss nor the connecting
rods. Instead, snap rings are fitted on both ends of the pins, preventing the\
pins from falling out. The No.1 compression ring is made of steel and the No.2 compression ring\
is made of cast iron. The oil
ring is m ade of a combination of steel and stainless steel. The outer diameter of\
each piston ring is slightly larger
than the diameter of the piston and the flexibility of the rings allows them\
to hug the cylinder walls when they
are mounted on the piston. Compression rings No.1 and No.2 work to prevent \
the leakage of gas from the cylin-
der and the oil ring works to scrape oil off the cylinder walls to prevent it from entering the combustion chamber. The cylinder block is made of aluminum alloy with a bank angle of 90 5. Cast iron cylinders are installed
inside the cylinder block. It has 8 cylinders which are approximately twice the length of th\
e piston stroke. The
top of each cylinder is closed off by the cylinder heads and the lower end of the cylinders becomes the crank-
case, in which the crankshaft is installed. In addition, the cylinder bl\
ock contains a water jacket, through which
coolant is pumped to cool the cylinders. The No.1 and No.2 oil pans are bolted onto the bottom of the cylinder block\
. The No.1 oil pan is made of
aluminum alloy. The No.2 oil pan is an oil reservoir made of pressed steel sheet. An o\
il level sensor is installed
in the No.1 oil pan (If the oil level drops below a set level, a warnin\
g light lights up.). A oil pan baffle plate keeps
sufficient oil in the bottom of the No.2 oil pan even when the vehicle is tilted. \
This dividing plate also prevents
the oil from making waves when the vehicle is stopped suddenly and the oil \
shifts away from the oil pump suction
pipe. Plastic region tightening bolts are used for the cylinder head, main bearing ca\
p and connecting rod.
EM±4
±
ENGINE MECHANICAL Operation
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PREPARATION
SST (SPECIAL SERVICE TOOLS)
±
ENGINE MECHANICAL PreparationEM±5
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SST (SPECIAL SERVICE TOOLS) (Cont'd)
RECOMMENDED TOOLS
EM±6±
ENGINE MECHANICAL Preparation
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EQUIPMENT
 


Part Name\
 
\

\
Note
 Caliper gauge\
 \

 


HC/CO meter
\
 
\

\

 


Compression gauge\
 
\

\
Cylinder compression pressure
 Connecting rod aligner\
 \

 


Cylinder gauge
\
 
\

\

 


Dial indicator
\
 
\

\

 


Engine turn±up tester\
 
\

\

 Feeler gauge\
 \

 


Micrometer
\
 
\

\

 


Precision straight edge\
 
\

\

 Spring tester\
 \
Valve spring
 


Steel square
\
 
\

\
Valve spring
 


Torque wrench\
 
\

\

 Vernier caliper\
 \

SSM (SPECIAL SERVICE MATERIALS)
 
Part Name
 
Part No.
\
 \

Use etc.  \
 \

Camshaft bearing cap  \
 \
Camshaft bearing ca
Cylinder head semi±circular plug 
Seal packing or equivalent
 
08826±00080
\
 \
Cylinder head semi±circular lug
Cylinder head cover Seal acking or equivalent 08826±00080\
 \
Cylinder head cover
Rear oil seal retainer  \
 \
Rear oil seal retainer
Oil pump  \
 \

Water inlet housing Seal packing 1282B,
Th b d 1282B i l t
 08826±00100\
 \
Water inlet housing
Water seal plate Three bond 1282B or equivalent 08826±00100\
 \
Water seal late
Water pump 

Adhesive 1324,
Three bond 1324 or equivalent
 

08833±00070
\
 

\
Drive plate mounting bolt
 
Adhesive 1344,
 \
 \

 Adhesive 1344,
Three bond 1344
,
 
08833±00080
\
 \

No.1 idler pulley mounting bolt Three bond 1344,
Loctite 242 or equivalent 08833±00080\
 \
No.1 idler ulley mounting bolt
±
ENGINE MECHANICAL PreparationEM±7
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