Lexus SC300 / Lexus SC400. Manual — part 443

37. DISCONNECT

ENGINE

WIRE

FROM LH CYLINDER HEAD

Remove the five bolts, and disconnect the engine wire.

38. REMOVE ENGINE HANGERS

Remove the two bolts and engine hanger. Remove the two
engine hangers.

39. REMOVE CYLINDER HEAD COVERS

Remove the eight bolts, seal washers, cylinder head cover
and gasket. Remove the two cylinder head covers.

40. IF NECESSARY, REMOVE SEMI–CIRCULAR PLUGS

41. REMOVE

CAMSHAFTS

NOTICE: Since the thrust clearance of the camshaft is
small, the camshaft must be held level while it is being
removed. If the camshaft is not kept level, the portion of
the cylinder head receiving the shaft thrust may crack or
be damaged, causing due the camshaft to seize or break.
To avoid this, the following steps should be carried out.

A.

Remove exhaust camshaft from RH cylinder head
(a) Bring the service bolt hole of the driven sub–gear

upward by turning the hexagon wrench head portion of
the exhaust camshaft with a wrench.

(b) Secure the exhaust camshaft sub–gear to the driven

gear with a service bolt.

Recommended service bolt:

Thread diameter 6 mm
Thread pitch 1.0 mm
Bolt length 16–20 mm (0.63–0.79 in.)

HINT: When removing the camshaft, make certain that the
torsional spring force of the sub–gear has been eliminated by
the above operation.

EM–70

–

ENGINE MECHANICAL

Cylinder Heads

(c) Set the timing mark (one dot mark) of the camshaft

driven gear at approx. 105 angle by turning the hexagon
wrench head portion of the exhaust camshaft with a
wrench.

(d) Alternately

loosen and remove the two bearing cap bolts

holding the intake camshaft side of the oil feed pipe to
the cylinder head.

(e) Uniformly loosen and remove the eight bearing cap

bolts in several passes in the sequence shown.

(f) Remove the oil feed pipe, four bearing caps and

exhaust camshaft.

B.

Remove intake camshaft from RH cylinder head
(a) Remove the rear bearing cap.
(b) Set the timing mark (one dot mark) of the camshaft drive

gear at approx. 455 angle by turning the hexagon
wrench head portion of the intake camshaft with a
wrench.

(c) Uniformly loosen and remove the eight bearing cap

bolts in several passes in the sequence shown.

(d) Remove the four bearing caps, oil seal and intake

camshaft.

–

ENGINE MECHANICAL

Cylinder Heads

EM–71

C.

Remove exhaust camshaft from LH cylinder head
(a) Bring the service bolt hole of the driven sub–gear

upward by turning the hexagon wrench head portion of
the exhaust camshaft with a wrench.

(b) Secure the exhaust camshaft sub–gear to the driven

gear with a service bolt.

Recommended service bolt:

Thread diameter 6 mm
Thread pitch 1.0 mm
Bolt length 16–20 mm (0.63–0.79 in.)

HINT: When removing the camshaft, make certain that the
torsional spring force of the sub–gear has been eliminated by
the above operation.
(c) Set the timing mark (two dot marks) of the camshaft

driven gear at approx. 155 angle by turning the hexagon
wrench head portion of the exhaust camshaft with a
wrench.

(d) Alternately

loosen and remove the two bearing cap bolts

holding the intake camshaft side of the oil feed pipe to
the cylinder head.

(e) Uniformly loosen and remove the eight bearing cap

bolts in several passes in the sequence shown.

(f) Remove the oil feed pipe, four bearing caps and

exhaust camshaft.

D.

Remove intake camshaft from LH cylinder head
(a) Remove the front bearing cap.
(b) Set the timing mark (one dot mark) of the camshaft drive

gear at approx. 605 angle by turning the hexagon
wrench head portion of the intake camshaft with a
wrench.

EM–72

–

ENGINE MECHANICAL

Cylinder Heads

(c) Uniformly loosen and remove the eight bearing cap

bolts in several passes in the sequence shown.

(d) Remove the four bearing caps, oil seal and intake

camshaft.

HINT: Arrange the bearing caps in correct order.

42. DISASSEMBLE EXHAUST CAMSHAFTS

(a) Mount the hexagon wrench head portion of the

camshaft in a vise.

NOTICE: Be careful not to damage the camshaft.

(b) Insert a service bolt (A) into the service hole of the

camshaft sub–gear.

(c) Using a screwdriver, turn the sub–gear clockwise, and

remove the service bolt (B).

NOTICE: Be careful not to damage the camshaft.

(d) Using snap ring pliers, remove the snap ring.

–

ENGINE MECHANICAL

Cylinder Heads

EM–73