1991 LEXUS SC400 compression ratio

25. REMOVE SPARK PLUGSUsing a 16 mm plug wrench, remove the 8 spark plugs.
26. IF RE±USING TIMING BELT, CHECK INSTALLATION MARKS ON TIMING BELT
Check that there are 4 installation marks on the timing belt by
turning the crankshaft pulley as shown in the illustration.
HINT: If the installation marks have disappeared, place a new
installation mark on the timing belt before removing each
part.
27. SET NO.1 CYLINDER TO TDC/COMPRESSION
(a) Turn the crankshaft pulley and align its groove with timing mark ª0º of the No.1 timing belt cover.
(b) Check that the timing marks of the camshaft timing pulleys and timing belt rear plates aligned.
If not, turn the crankshaft 1 revolution (360 5).
28. REMOVE TIMING BELT TENSIONER HINT:
wWhen re±using timing belt:
If the installation marks have disappeared, before re-
move the timing belt, place new installation marks on
the timing belt to match the timing marks of the camshaft
timing pulleys, and place the a new installation mark on
the timing belt to match the end of the hydraulic pump.
±
1UZ±FE ENGINE ENGINE MECHANICALEG±53
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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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RECOMMENDED TOOLS (Cont'd)
For suspending engine
09090±04010Engine Sling
Device
Plug for the vacuum hose. fuel hose etc.
09258±00030Hose Plug Set
09200±00010Engine Adjust
Kit
EQUIPMENT
 Part Name\
 \
Note
 Caliper gauge\
 \

 CO/HC analyzer\
 \

 

Compression gauge
\
 
\

\
Cylinder compression pressure
 Connecting rod aligner\
 \

 Cylinder gauge\
 \

 Dial indicator\
 \

 

Engine tune±up tester
\
 
\

\

 Feeler gauge\
 \

 Micrometer\
 \

 

Straight edge\
 
\

\

 Spring tester\
 \
Valve spring
 Steel square\
 \
Valve spring
 Torque wrench\
 \

 

Vernier caliper
\
 
\

\

SSM (SPECIAL SERVICE MATERIALS)
 

Part Name 

Part No.\
 

\
Use etc.
 

Seal packing or equivalent 

08826±00080\
 

\

Camshaft bearing cap, Cylinder head cover,
Rear oil seal retainer and Oil pump
 




Adhesive 1324,
THREE BOND 1324 or equivalent
 




08833±00070
\
 



\

Drive plate mounting bolt
 




Adhesive 1344,
THREE BOND 1344,
LOCTITE 242 or equivalent 




08833±00080
\
 



\

Idler pulley mounting bolt
EM±6±
ENGINE MECHANICAL Preparation
WhereEverybodyKnowsYourName

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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9. REMOVE NO. 3, NO. 1 AND NO. 2 CYLINDER HEADCOVERS
(a) Remove the 12 bolts and four nuts.
(b) Remove the cylinder head covers and gaskets.
10. SET NO. 1 CYLINDER TO TDC/COMPRESSION (a) Turn the crankshaft pulley and align its groove withtiming mark º0º of the No. 1 timing belt cover.
NOTICE: Always turn the crankshaft clockwise.
(b) Check that the timing marks of the camshaft timing pulleys are aligned with the timing marks of the No. 4
timing belt cover.
If not, turn the crankshaft one revolution (360 5).
11. INSPECT VALVE CLEARANCE (a) Uniformly tighten the bearing cap bolts in severalpasses.
Torque: 20 N Vm (200 kgf Vcm, 14 ft Vlbf)
(b) Check only those valves indicated in the illustration.
w Using a feeler gauge, measure the clearance
between the valve lifter and camshaft.
w Record the valve clearance measurements of
those that are out of specification. They will be used
later to determine the required replacement
adjusting shim.
Valve clearance (Cold):
Intake 0.15±0.25 mm (0.006±0.010 in.)
Exhaust 0.25±0.35 mm (0.010±0.014 in.)
EM±12±
ENGINE MECHANICAL Engine Tune±Up
WhereEverybodyKnowsYourName

REMOVAL OF TIMING BELT
(See Components on page EM±23)1. REMOVE WATER PUMP PULLEY AND RADIATOR (See steps 1 to 3, 6 and 7 on pages EM±64 and 66)
2. REMOVE NO. 3 AND NO. 2 TIMING BELT COVERS (a) Remove the oil filler cap.
(b) Using a 5 mm hexagon wrench, remove the nine bolts,No. 3, No. 2 timing belt covers and gasket.
3. REMOVE DRIVE BELT TENSIONER Remove the three bolts and tensioner.
4. SET NO. 1 CYLINDER TO TDC/COMPRESSION (a) Turn the crankshaft pulley and align its groove withtiming mark º0º of the No. 1 timing belt cover.
NOTICE: Always turn the crankshaft clockwise.
(b) Check that the timing marks of the camshaft timing pulleys are aligned with the timing marks of the No. 4
timing belt cover.
If not, turn the crankshaft one revolution (360 5).
5. REMOVE TIMING BELT FROM CAMSHAFT TIMING PULLEYS
HINT: (Re±using timing belt)
Place matchmarks on the timing belt and camshaft timing
pulleys as shown in the illustration.
EM±24
±
ENGINE MECHANICAL Timing Belt
WhereEverybodyKnowsYourName

22. REMOVE ALTERNATOR(a) Disconnect the alternator connector.
(b) Remove the cap and nut, and disconnect the alternatorwire.
(c) Remove the bolt, and disconnect the A/T oil cooler pipe bracket.
(d) Remove the nut and alternator.
23. REMOVE DRIVE BELT TENSIONER Remove the bolt, two nuts and tensioner.
24. REMOVE SPARK PLUGS Using a 16 mm plug wrench, remove the eight spark plugs.
25. IF RE±USING TIMING BELT, CHECK INSTALLATION MARKS ON TIMING BELT
Check that there are four installation marks on the timing belt
by turning the crankshaft pulley as shown in the illustration.
If the installation marks have disappeared, place a new
installation mark on the timing belt before removing each
part.
26. SET NO.1 CYLINDER TO TDC/COMPRESSION (a) Turn the crankshaft pulley and align its groove with thetiming mark ºOº of the No.1 timing belt cover.
EM±40
±
ENGINE MECHANICAL Timing Belt
WhereEverybodyKnowsYourName

2. INSTALL RELIEF VALVE(a) Slighty mount the pump body in a vise.
NOTICE: Be careful not to damage the pump body.
(b) Insert the relief valve and compression spring into the oil
pump body hole.
(c) Install the plug with a new gasket.
Torque: 49 N Vm (500 kgf Vcm, 36 ft Vlbf)
INSTALLATION OF OIL PUMP
(See Components on page LU±9)
1. INSTALL OIL PUMP (a) Place two new O±rings in position on the cylinder block.
(b) Remove any old packing (FIPG) material and be careful
not to drop any oil on the contact surfaces of the oil
pump cylinder block.
w Using a razor blade gasket scraper, remove all the
old packing (FIPG) material from the gasket
surfaces and sealing groove.
w Thoroughly clean all components to remove all the
debris.
w Using a non±residue solvent, clean both sealing
surfaces.
NOTICE: Do not use a solvent which will affect the
painted surfaces.
(c) Apply seal packing to the oil pump as shown in the illustration.
Seal packing: Part No. 08826±00080 or equivalent
w Install a nozzle that has been cut to a 2±3 mm
(0.08±0.12 in.) opening.
HINT: Avoid applying an excessive amount to the surface. Be
particularly careful near oil passages. w Parts must be assembled within 5 minutes of
application. Otherwise the material must be
removed and reapplied.
w Immediately remove nozzle from the tube and
reinstall cap.
±
LUBRICATION SYSTEM Oil PumpLU±15
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