engine LEXUS SC400 1991 Service Repair Manual

16. REMOVE LH CYLINDER HEAD COVER(a) Remove the two bolts holding the high±tension cordclamp to the cylinder head.
(b) Disc onnect the high±tension cords from the spark
plugs.
(c) Disconnect the high±tension cords from the front high±tension cord clamp.
(d) Disconnect the engine wire from the two wire clamps on
the LH delivery pipe.
(e) Disconnect the four injector connectors.
(f) Disconnect the two engine wire connectors.
(g) Remove the eight bolts, seal washers, cylinder head
cover and gasket.
19. SET NO.1 CYLINDER TO TDC/COMPRESSION (a) Turn the crankshaft pulley, and align its groove with thetiming mark º0º of the No.1 timing belt cover.
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(b) Check that the timing marks of the camshaft timingpulleys and timing belt rear plates aligned.
If not, turn the crankshaft one revolution (360 5) and align the
mark as above.
20. INSPECT VALVE CLEARANCE (a) Check only those valves indicated.w Using a feeler gauge, measure the clearance
between the valve lifter and camshaft.
w Record the out±of±specification valve clearance
measurements. 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.)
(b) Turn the crankshaft one revolution (360 °), and align the
mark as above. (See procedure step in 19 (a))
(c) Check only the valves indicated as shown. Measure the
valve clearance.
(See procedure in step (a))
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21. REMOVE THEFT DETERRENT HORN(a) Disconnect the connector.
(b) Remove the bolt and theft deterrent horn.
HINT: Remove the deterrent horn when the valve clearance
is adjusted for the front portion of the exhaust camshaft on
the LH cylinder head.
22. ADJUST VALVE CLEARANCE (a) Remove the adjusting shim.w Turn the crankshaft, and position the cam lobe of
the camshaft on the adjusting valve upward.
w Position the hole of the adjusting shim toward the
spark plug side.
w Press down the valve lifter with SST (A), and place
SST (B) between the camshaft and valve lifter
flange. Remove SST (A).
SST 09248±55011 (09248±05011 (A), 09248±05021 (B))
NOTICE: The valve lifter is made of aluminum, which is
easily scratched. So when setting SST (B), take care not
to scratch the face of the valve lifter.
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Using compressed air and magnetic finger, removethe adjusting shim by blowing air into the shim hole.
HINT: Remove the adjusting shim from the intake man-
ifold side.
NOTICE: Do not drop the adjusting shim into por-
tions A and B. If dropped into portion A, the adjust-
ing shim will pass through the cylinder head and
cylinder block into the oil pan. If dropped into por-
tion B, the adjusting shim cannot be recovered with-
out removing the exhaust camshaft.
inspNFO
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(b) Determine the replacement adjusting shim sizefollowing Formula or Charts:
w Using a micrometer, measure the thickness of the
removed shim.
w Calculate the thickness of a new shim so the valve
clearance comes within specified value.
T
Thickness of used shim
A
Measured valve clearance
N
Thickness of new shim
Intake N = T + (A±0.20 mm (0.008 in.))
Exhaust N = T + (A±0.30 mm (0.012 in.))
w Select a new shim with a thickness as close as
possible to the calculated values.
HINT: Shims are available in thirty±three sizes in increments
of 0.025 mm (0.0010 in.), from 2.50 mm (0.0984 in.) to 3.30
mm (0.1299 in.).
(c) Install a new adjusting shim. w Place a new adjusting shim on the valve lifter.
w Press down the valve lifter with SST (A), and
remove SST (B).
SST 09248±55011
(d) Recheck the valve clearance.
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Adjusting Shim Selection Chart (Intake)
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Adjusting
Shim
Selection
Chart
(Exhaust)
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23. REINSTALL THEFT DETERRENT HORN(a) Install the theft deterrent horn with the bolt.
(b) Connect the connector.
24. REINSTALL RH CYLINDER HEAD COVER (a) Remove any oil packing (FIPG) material.
(b) Apply seal packing to the cylinder head as shown in theillustration.
Seal packing: Part No. 08826±00080 or equivalent
(c) Install the gasket to the cylinder head cover.
(d) Install the seal washer to the mounting bolt.
(e) Install the cylinder head cover with the eight bolts.
Torque: 5.9 N Vm (60 kgf Vcm, 52 in. Vlbf)
(g) Connect the four high±tension cords to the spark plugs.
(h) Install the rear and front high±tension cord clamps with
the two bolts.
HINT: Place the front and rear ends of the front high±tension
cord clamp on the rear high±tension cord clamp and lower
high±tension cord cover.
(i) Fit the high±tension cords to the high±tension cord clamps. (See page IG±16)
25. REINSTALL LH CYLINDER HEAD COVER (a) Remove any oil packing (FIPG) material.
(b) Apply seal packing to the cylinder head as shown in theillustration.
Seal packing: Part No. 08826±00080 or equivalent
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(c) Install the gasket to the cylinder head cover.
(d) Install the seal washer to the mounting bolt.
(e) Install the cylinder head cover with the eight bolts.
Torque: 5.9 NVm (60 kgf Vcm, 52 in. Vlbf)
(f) Connect the two engine wire connectors.
(g) Connect the four injector connectors.
(h) Install the engine wire to the two wire clamps on the
delivery pipe.
(i) Connect the four high±tension cords to the spark plugs.
(j) Install the rear and front high±tension cord clamps with the two bolts.
HINT: Place the front and rear ends of the front high±tension
cord clamp on the rear high±tension cord clamp and lower
high±tension cord cover.
(k) Fit the high±tension cords to the high±tension cord clamps. (See page IG±16)
26. REINSTALL THROTTLE BODY (a) Connect the following hoses:(1) PCV hose from throttle body
(2) Water by±pass hose from throttle body
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(b) Install a new gasket and throttle body with the two boltsand two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT: Use bolts 40 mm (1.57 in.) in length.
(c) Install the water by±pass pipe (from rear water by±pass
joint) to the clamp on the engine wire cover.
(d) Connect the following hoses: (1) Water by±pass hose to the ISC valve
(2) (USA Spec.) Vacuum hose to throttle body
(3) (Exc. USA Spec.) Three vacuum hoses to throttle body
(e) Connect the following connectors: (1) Throttle position sensor connector
(2) (w/ TRAC) Sub±throttle position sensor connector
(3) (w/ TRAC) Sub±throttle actuator
27. REINSTALL HEATER WATER VALVE (a) Install the water valve and bracket assembly with thetwo bolts.
(b) Install the engine wire clamp with the bolt.
(c) Connect the VSV connector.
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