engine LEXUS SC400 1991 Service Repair Manual

B. Install cylinder head boltsHINT:
wThe cylinder head bolts are tighten in two progressive
steps (steps (c) and (e)).
w If any one of the cylinder head bolts broken or deformed,
replace it.
(a) Apply a light coat of engine oil on the threads and under
the heads of the cylinder head bolts.
(b) Te mp o ra rily in sta ll th e twe n ty pla te wa sh e rs an d cylinder head bolts.
(c) Uniformly tighten the ten cylinder head bolts on one side
of the cylinder head in several passes in the sequence
shown, then do the other side as shown.
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
If any one of the bolts does not meet the torque specification,
replace the bolt.
(d) Mark the front of the cylinder head bolt head with paint.
(e) Retighten the cylinder head bolts 90 ° in the numerical
order shown.
(f) Check that the painted mark is now at a 90 ° angle to
front.
4. CONNECT MAIN OXYGEN SENSOR CONNECTORS Connect the RH and LH oxygen sensor connector.
5. INSTALL CIRCULAR PLUGS (a) Place two new circular plugs in position on the cylinderheads, facing the cup side forward.
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(b) Remove any old packing (FIPG) material.
(c) Apply seal packing to the bearing caps as shown.
Seal packing: Part No. 08826±00080 or equivalent
(d) (RH Cylinder Head)Install the bearing cap (mark ºI1º) in position with the ar-
row mark facing rearward.
(e) (LH Cylinder Head) Install the bearing cap (mark ºI6º) in position with the ar-
row mark facing forward.
(f) Install a new seal washer to the bearing cap bolt.
(g) Apply a light of engine oil on the threads of the bearing
cap bolt.
(h) Install the four bearing cap bolts.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
HINT: Use silver colored bolts 38 mm (1.50 in.) in length.
6. ASSEMBLE EXHAUST CAMSHAFTS (a) Install the following parts:(1) Camshaft gear spring
(2) Camshaft sub±gear
(3) Wave washer
(b) Using snap ring pliers, install the snap ring.
(c) M ount the hexagon wrench head portion of the
camshaft in a vice.
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(d) Insert a service bolt (A) into the service hole of thecamshaft sub±gear.
(e) Using a screwdriver, align the service holes and teeth of the camshaft driven gear and sub±gear by turning
camshaft sub±gear clockwise, and install a service bolt
(B).
NOTICE: Be careful not to damage the camshaft.
(f) Remove the service bolt (A).
7. INSTALL CAMSHAFTS NOTICE: Since the thrust clearance of the camshaft is
small, the camshaft must be held level while it is being
installed. If the camshaft is not kept level, the portion of
the cylinder head receiving the shaft thrust may crack or
be damaged causing the camshaft to seize or break. To
avoid this, the following steps should be carried out.
A. Install intake camshaft to RH cylinder head (a) Apply MP grease to the thrust portion of the camshaft.
(b) Place the intake camshaft at 45 ° angle of the timing
mark (one dot mark) on the cylinder head.
(c) Remove any old packing (FIPG) material.
(d) Apply seal packing to the bearing cap (mark ºI6º) as shown.
Seal packing: Part No. 08826±00080 or equivalent
(e) Install the front bearing cap (mark ºI6º) with the arrow mark facing rearward.
HINT:
w Installing the front bearing cap will determine the thrust
position of the camshaft.
w Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
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(f) Install the other bearing caps in the sequence shownwith the arrow mark facing rearward.
HINT: Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
(g) Apply a light coat of engine oil on the threads and under
the heads (A only) of the bearing cap bolts.
HINT: Do not apply engine oil under the heads of the bearing
cap bolts (B).
(h) Install a new seal washer to the bearing cap bolt (B).
Install the eight bearing cap bolts as shown.
HINT:
w Use bearing cap bolts 38 mm (1.50 in.) in length. The
bolts are black (A) or silver (B) in color. Install the two
silver bolts to the front bearing cap. Install the six black
bolts to the other positions.
w After installing the oil feed pipe, install the two bolts to
the rear bearing cap as directed in step B (i).
(i) Uniformly tighten the eight bearing cap bolts in several passes in the sequence shown.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
B. Install exhaust camshaft to RH cylinder head
(a) Set the timing mark ( one dot mark) of the camshaft drive
gear at 105 angle by turning the hexagon wrench head
portion of the intake camshaft with a wrench.
(b) Apply MP grease to the thrust portion of the exhaust camshaft.
(c) Align the timing marks (one dot mark) of the camshaft
drive and driven gears.
(d) Place the exhaust camshaft on the cylinder head.
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(e) Check that the exhaust camshaft moves smoothly in the
thrust direction.
(f) Install the rear bearing cap with the arrow mark facing rearward.
HINT:
w Installing the rear bearing cap will determine the thrust
position of the camshaft.
w Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
(g) Install the other bearing caps in the sequence shown with the arrow mark facing rearward.
HINT: Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
(h) Apply a light coat of engine oil on the threads and under
the heads of the bearing cap bolts.
(i) Install the oil feed pipe and ten bolts.
HINT: Use bearing cap bolts 38 mm (1.50 in.) and 52 mm
(2.05 in.) in length. Use black colored 38 mm (1.50 in.) bolts.
Install the two 52 mm (2.05 in.) bolts in outside positions of
the oil pipe. Install the eight 38 mm (1.50 in.) bolts in the other
positions.
(j) Uniformly tighten the eight bearing cap bolts on the bearing caps of the exhaust camshaft in several passes
in the sequence shown.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
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(k) Alternately tighten the two bearing cap bolts on the rearbearing cap of the intake camshaft in several passes.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
(l) Bring the service bolt installed in the driven subgear
upward by turning the hexagon wrench head portion of
the camshaft with a wrench.
(m) Remove the service bolt.
C. Install intake camshaft to LH cylinder head (a) Apply MP grease to the thrust portion of the camshaft.
(b) Place the intake camshaft at 60 ° angle of the timing
mark (one dot mark) on the cylinder head.
(c) Remove any old packing (FIPG) material.
(d) Apply seal packing to the bearing cap (mark ºI1º) as shown.
Seal packing: Part No. 08826±00080 or equivalent
(e) Install the front bearing cap (mark ºI1º) with the arrow
mark facing forward.
HINT:
w Installing the front bearing cap will determine the thrust
position of the camshaft.
w Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
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(f) Install the other bearing caps in the sequence shownwith the arrow mark facing forward.
HINT: Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
(g) Apply a light coat of engine oil on the threads and under
the heads (A only) of the bearing cap bolts.
HINT: Do not apply engine oil under the heads of the bearing
cap bolts (B).
(h) Install a new seal washer to the bearing cap bolt (B).
Install the eight bearing cap bolts as shown.
HINT:
w Use bearing cap bolts 38 mm (1.50 in.) in length. The
bolts are black (A) or silver (B) in color. Install the two
silver bolts to the front bearing cap. Install the six black
bolts to the other positions.
w After installing the oil feed pipe, install the two bolts to
the bearing cap second from the front as directed in step
D (i).
(i) Uniformly tighten the eight bearing cap bolts in several passes in the sequence shown.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
D. Install exhaust camshaft to LH cylinder head
(a) Set the timing mark (two dot marks) of the camshaftdrive gear at 15 ° angle by turning the hexagon wrench
head portion of the intake camshaft with a wrench.
(b) Apply MP grease to the thrust portion of the exhaust camshaft.
(c) Align the timing marks (two dot marks) of the camshaft
drive and driven gears.
(d) Place the exhaust camshaft on the cylinder head.
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(e) Check that the exhaust camshaft moves smoothly in the
thrust direction.
(f) Install the front bearing cap with the arrow mark facing forward.
HINT:
w Installing the front bearing cap will determine the thrust
position of the camshaft.
w Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
(g) Install the other bearing caps in the sequence shown with the arrow mark facing forward.
HINT: Align the arrow marks at front and rear of the cylinder
head with the mark on the bearing cap.
(h) Apply a light coat of engine oil on the threads and under
the heads of the bearing cap bolts.
(i) Install the oil feed pipe and ten bolts.
HINT: Use bearing cap bolts 38 mm (1.50 in.) and 52 mm
(2.05 in.) in length. Use black colored 38 mm (1.50 in.) bolts.
Install the two 52 mm (2.05 in.) bolts in outside positions of
the oil pipe. Install the eight 38 mm (1.50 in.) bolts in the other
positions.
(j) Uniformly tighten the eight bearing cap bolts on the
bearing caps of the exhaust camshaft in several passes
in the sequence shown.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
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(k) Alternately tighten the two bearing cap bolts on thebearing cap of the intake camshaft second from the front
in several passes.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
(l) Bring the service bolt installed in the driven subgear
upward by turning the hexagon wrench head portion of
the camshaft with a wrench.
(m) Remove the service bolt.
8. CHECK AND ADJUST VALVE CLEARANCE (See steps 19 to 23 on pages EM±15 to 22)
Turn the camshaft, and position the cam lobe upward, check
and adjust the valve clearance.
Valve clearance:
Intake 0.15±0.25 mm (0.006±0.010 in.)
Exhaust 0.25±0.35 mm (0.010±0.014 in.)
9. INSTALL CAMSHAFT OIL SEALS(a) Apply MP grease to a new oil seal lip.
(b) Using SST and a hammer, tap in the two oil seals.
SST 09223±46011
10. INSTALL SEMI±CIRCULAR PLUGS (a) Remove any oil packing (FIPG) material.
(b) Apply seal packing to the semi±circular plug groove.
Seal packing: Part No. 08826±00080 or equivalent
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(c) Install the four semi±circular plugs.
11. INSTALL CYLINDER HEAD COVERS (a) Remove any oil packing (FIPG) material.
(b) Apply seal packing to the cylinder heads as shown in the
figure.
Seal packing: Part No.08826±00080 or equivalent
(c) Install the gasket to the cylinder head cover.
(d) Install the seal washer to the bolt. Install the cylinder head cover with the eight bolts. Uniformly tighten the
bolts. Install the two cylinder head covers
Torque: 5.9 N Vm (60 kgf Vcm, 52 in. Vlbf)
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