1991 LEXUS SC400 engine

(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 HEATED OXYGEN SENSOR CONNECTORS
Connect the RH and LH oxygen sensor connectors.
5. INSTALL CIRCULAR PLUGS
(a) Place 2 new circular plugs in position on the cylinder heads, facing the cup side forward.
(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
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(d) RH Cylinder Head:Install the bearing cap (mark ª11º) in position with the arrow
mark facing rearward.
(e) LH Cylinder Head: Install the bearing cap (mark ª16º) in position with the arrow
mark facing forward.
(f) Install a new seal washer to the bearing cap bolt.
(g) Apply a light coat of engine oil on the threads of the bearing
cap bolt.
(h) Install the 4 bearing cap bolts. Alternately tighten 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 CAMSHAFT
(a) Install the following parts: (1) Camshaft gear spring
(2) Camshaft sub±gear
(3) Wave washer
HINT: Align the pins on the gears with the spring ends.
(b) Using snap ring pliers, install the snap ring.
(c) Mount the hexagon wrench head portion of the camshaft in a vise.
NOTICE: Be careful not to damage the camshaft.
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(d) Insert service bolt A into the service hole of the camshaftsub±gear.
(e) Using a screwdriver, align the holes of the camshaft drive
gear and sub±gear by turning camshaft subgear clockwise,
and temporarily install service bolt B.
NOTICE: Be careful not to damage the camshaft.
(f) Align the gear teeth of the drive gear and sub±gear, and
tighten service bolt B.
7. INSTALL CAMSHAFTS
NOTICE: Since the thrust clearance of the camshaft is small,
the camshaft must be kept level while it is being installed. If the
camshaft is not kept level, the portion of the cylinder head re-
ceiving 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 intake camshaft.
(b) Place the intake camshaft at 45
angle of the timing mark (1
dot mark) on the cylinder head.
(c) Remove any old packing (FIPG) material.
(d) Apply seal packing to the bearing cap (mark ª16º) as shown.
Seal packing: Part No. 08826±00080 or equivalent
(e) Install the front bearing cap (mark ª16º) with the arrow markfacing rearward.
HINT:
wInstalling the front bearing cap will determine the thrust
portion of the camshaft.
w Align the allow marks at the front and rear of the cylinder
head with the mark on the bearing cap.
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(f) Install the other 4 bearing caps in the sequence shown withthe arrow marks facing rearward.
HINT: Align the arrow marks at the front and rear of the cylin-
der 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 bolt (B).
(h) Install a new seal washer to the bearing cap bolt (B). Install the 8 bearing cap bolts as shown.
HINT:
wUse bearing cap bolts 38 mm (1.50 in.) in length. The
bolts are black (A) or silver (B) in color. Install the 2 silver
bolts to the front bearing cap. Install the 6 black bolts to
the other positions.
w After installing the oil feed pipe, install the 2 bolts to rear
bearing cap as directed in step B (i).
(i) Uniformly tighten the 8 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 (1 dot mark) of the camshaft drive gear
at 10
angle by turning the hexagon wrench head portion of
the intake camshaft with a wrench.
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(b) Apply MP grease to the thrust portion of the exhaustcamshaft.
(c) Align the timing marks (1 dot mark) of the camshaft drive and
driven gears.
(d) Place the exhaust camshaft on the cylinder head.
(e) Check that the exhaust camshaft moves smoothly in the thrust direction.
(f) Install the rear bearing cap (mark ªE1º) with the arrow mark facing rearward.
HINT:
wInstalling the rear bearing cap will determine the thrust
portion of the camshaft.
w Align the allow marks at the front and rear of the cylinder
head with the mark on the bearing cap.
(g) Install the other 3 bearing caps in the sequence shown with the arrow marks facing rearward.
HINT: Align the arrow marks at the front and rear of the cylin-
der 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 10 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 feed pipe. Install the eight 38 mm (1.50 in.) bolts in the
other positions.
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(j) Uniformly tighten the 8 bolts on the bearing caps of theexhaust camshaft in several passes, in the sequence shown.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
(k) Alternately tighten the 2 bolts on the rear bearing caps of the
intake camshaft in several passes.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
(l) Boring 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 intake camshaft.
(b) Place the intake camshaft at 60
angle of the timing mark (1
dot mark) on the cylinder head.
(c) Remove any old packing (FIPG) material.
(d) Apply seal packing to the bearing cap (mark ª11º) as shown.
Seal packing: Part No. 08826±00080 or equivalent
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(e) Install the front bearing cap (mark ª11º) with the arrow markfacing forward.
HINT:
wInstalling the front bearing cap will determine the thrust
portion of the camshaft.
w Align the allow marks at the front and rear of the cylinder
head with the mark on the bearing cap.
(f) Install the other 4 bearing caps in the sequence shown with the arrow marks facing rearward.
HINT: Align the arrow marks at the front and rear of the cylin-
der 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 bolt (B).
(h) Install a new seal washer to the bearing cap bolt (B). Install the 8 bearing cap bolts as shown.
HINT:
wUse bearing cap bolts 38 mm (1.50 in.) in length. The
bolts are black (A) or silver (B) in color. Install the 2 silver
bolts to the front bearing cap. Install the 6 black bolts to
the other positions.
w After installing the oil feed pipe, install the 2 bolts to the
bearing cap 2nd from the front as directed in step B (i).
(i) Uniformly tighten the 8 bearing cap bolts in several passes, in the sequence shown.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
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D. Install exhaust camshaft to LH cylinder head
(a) Set the timing mark (2 dot marks) of the camshaft drive gearat 15
angle by turning the hexagon wrench head portion of
the intake camshaft with a wrench.
(b) A p p ly MP gre a se to th e th ru st po rtio n of th e ex haust
camshaft.
(c) Align the timing marks (2 dot marks) of the camshaft drive and
driven gears.
(d) Place the exhaust camshaft on the cylinder head.
(e) Check that the exhaust camshaft moves smoothly in the thrust direction.
(f) Install the front bearing cap (mark ªE1º) with the arrow mark facing forward.
HINT:
wInstalling the front bearing cap will determine the thrust
portion of the camshaft.
w Align the allow marks at the front and rear of the cylinder
head with the mark on the bearing cap.
(g) Install the other 3 bearing caps in the sequence shown with the arrow marks facing forward.
HINT: Align the arrow marks at the front and rear of the cylin-
der head with the mark on the bearing cap.
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