light LEXUS SC400 1991 Service Repair Manual

(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).
27. REMOVE TIMING BELT TENSIONER HINT:
w(Re±using timing belt)
If the installation marks have disappeared, before re-
moving the timing belt, place new installation marks on
the timing belt to match the timing marks of the camshaft
timing pulleys, and place a new installation mark on the
timing belt to match the end of the hydraulic pump.
w (When replacing timing belt tensioner only)
To avoid meshing of the timing pulley and timing belt, se-
cure one of them with string. And place matchmarks on
the timing belt and RH camshaft timing pulley.
Alternately loosen the two bolts, and remove them, the ten-
sioner and dust boot.
28. DISCONNECT TIMING BELT FROM CAMSHAFT TIMING PULLEYS
(a) Using SST, loosen the tension between the LH and RHcamshaft timing pulleys by slightly turning the LH
camshaft timing pulley clockwise.
SST 09278±54012
±
ENGINE MECHANICAL Timing BeltEM±41
WhereEverybodyKnowsYourName

11. INSTALL LH CAMSHAFT TIMING PULLEY(a) Align the knock pin on the camshaft with the knock pingroove of the timing pulley.
(b) Slide the timing pulley, facing the ºLº mark forward.
(c) Using SST, install and torque the pulley bolt.
SST 09278±54012
Torque: 108 N Vm (1,100 kgf Vcm, 80 ft Vlbf)
12. SET NO.1 CYLINDER TO TDC/COMPRESSION
(a) (Crankshaft Pulley Position)Turn the crankshaft pulley, and align its groove with the
ºOº timing mark of the No.1 timing belt cover.
(b) (Camshaft Timing Pulley Position) Using SST, t urn the camshaft timing pulley, and align the
timing marks of the camshaft timing pulley and timing
belt rear plate.
SST 09278±54012
13. INS TALL TIMING BE LT TO LH CAMS HAFT TIMING PULLEY
(a) Align the installation mark on the timing belt with the end
of the hydraulic pump.
(b) Remove any oil or water on the LH camshaft timing pulley, and keep it clean.
(c) Using SST, slightly turn the LH camshaft timing pulley
clockwise. Align the installation mark on the timing belt
with the timing mark of the camshaft timing pulley, and
hang the timing belt on the LH camshaft timing pulley.
SST 09278±54012
±
ENGINE MECHANICAL Timing BeltEM±49
WhereEverybodyKnowsYourName

(d) Using SST, align the timing marks of the LH camshaftpulley and timing belt rear plate.
SST 09278±54012
(e) Check that the timing belt has tension between the crankshaft timing pulley and LH camshaft timing pulley.
14. INSTALL TIMING BELT TO RH CAMSHAFT TIMING PULLEY
(a) Remove any oil or water on the RH camshaft timing andwater pump pulley, and keep them clean.
(b) Using SST, slightly turn the RH camshaft timing pulley clockwise. Align the installation mark on the timing belt
with the timing mark of the camshaft timing pulley, and
hang the timing belt on the RH camshaft timing pulley.
SST 09278±54012
(c) Using SST, align the timing marks of the RH camshaft pulley and timing belt rear plate.
SST 09278±54012
(d) Check that the timing belt has tension between the RH
camshaft timing pulley and LH camshaft pulley.
15. SET TIMING BELT TENSIONER (a) Using a press, slowly press in the push rod using981±9,807 N (100±1,000 kgf, 220±2,205 lbf) of
pressure.
(b) Align the holes of the push rod and housing, pass a 1.27
mm hexagon wrench through the holes to keep the
setting position of the push rod.
(c) Release the press.
(d) Install the dust boot to the tensioner.
EM±50
±
ENGINE MECHANICAL Timing Belt
WhereEverybodyKnowsYourName

8. INSPECT AND CLEAN VALVE SEATS(a) Using a 45
carbide cutter, resurface the valve seats.
Remove only enough metal to clean the seats.
(b) Check the valve seating position.
Apply a thin coat of prussian blue (or white lead) to the valve
face. Lightly press the valve against the seat. Do not rotate
the valve.
(c) Check the valve face and seat for the following: w If blue appears 360
around the face, the valve is
concentric. If not, replace the valve.
w If blue appears 360
around the valve seat, the
guide and face are concentric. If not, resurface the
seat.
w Check that the seat contact is in the middle of the
valve face with the following width:
Intake 1.0±1.4 mm (0.039±0.055 in.)
Exhaust 1.2±1.6 mm (0.047±0.063 in.)
If not, correct the valve seats as follows:
(1) If the seating is too high on the valve face, use 15 5
and 45 5 cutters to correct the seat.
(2) If the seating is too low on the valve face, use 75 5
and 45 5 cutters to correct the seat.
±
ENGINE MECHANICAL Cylinder HeadEM±47
WhereEverybodyKnowsYourName

(d) Using a plastic±faced hammer, lightly tap the valve stem
tip to assure proper fit.
4. INSTALL VALVE LIFTERS AND SHIMS (a) Install the valve lifter and shim.
(b) Check that the valve lifter rotates smoothly by hand.
INSTALLATION OF CYLINDER HEAD
(See Components on pages EM±34 and 35)1. INSTALL CYLINDER HEAD
A. Place cylinder head on cylinder block (a) Place a new cylinder head gasket in position on thecylinder block.
NOTICE: Be sure to install it correctly.
(b) Place the cylinder head in position on the cylinder head
gasket and connect the heater water hose to the union.
B. Install cylinder head bolts
HINT:
wThe cylinder head bolts are tightened in two progressive
steps (steps (c) and (f)).
w If any of bolts break or deform, replace them.
(a) Apply a light coat of engine oil on the threads and under
the heads of the cylinder head bolts.
(b) Install the 14 plate washers to each cylinder head bolt.
(c) First, using a 10 mm bi±hexagon wrench, uniformly tighten the cylinder head bolts in several passes in the
sequence shown.
Torque: 34 N Vm (350 kgf Vcm, 25 ft Vlbf)
If any one of the bolts does not meet the torque specification,
replace the bolt.
EM±54
±
ENGINE MECHANICAL Cylinder Head
WhereEverybodyKnowsYourName

(d) Mark the front of the cylinder head bolt head with paint.
(e) Second retighten the cylinder head bolts 90
in the
numerical order shown above.
(f) Third retighten cylinder head bolts by an additional 90
.
(g) Check that the painted mark is now turned to the rear.
2. INSTALL CAMSHAFTS (a) Apply engine oil to the thrust portion of the camshaft.
(b) Place the camshaft on the cylinder head with the camlobe facing up as shown.
(c) Place the No.3 and No.7 bearing caps in their proper location.
(d) Apply a light coat of engine oil on the threads and under
the heads of the bearing cap bolts.
(e) Temporarily tighten these bearing cap bolts uniformly
and alternately in several passes until the bearing caps
are snug with the cylinder head.
±
ENGINE MECHANICAL Cylinder HeadEM±55
WhereEverybodyKnowsYourName

(f) Apply MP grease to a new camshaft oil seal lip.
(g) Install the oil seal to the camshaft.
(h) Clean the installed surfaces of the No. 1 bearing capand cylinder head with cleaner.
(i) Apply seal packing to the No. 1 bearing cap as shown.
Seal packing: Part No. 08826±00080 or equivalent
(j) Install other bearing caps in their proper locations.
(k) Apply a light coat of engine oil on the threads and under
the heads of the bearing cap bolts.
(l) Install and uniformly tighten the 14 bearing cap bolts on
one side in several passes in the sequence shown.
Torque: 20 N Vm (200 kgf Vcm, 14 ft Vlbf)
EM±56±
ENGINE MECHANICAL Cylinder Head
WhereEverybodyKnowsYourName

(d) Check the valve overall length.
Standard overall length:Intake 94.95 mm (3.7382 in.)
Exhaust 96.90 mm (3.8150 in.)
Minimum overall length: Intake 94.45 mm (3.7185 in.)
Exhaust 96.40 mm (3.7953 in.)
If the overall length is less than minimum, replace the valve.
(e) Check the surface of the valve stem tip for wear.
If the valve stem tip is worn, resurface the tip with a grinder
or replace the valve.
NOTICE: Do not grind off more than the minimum overall
length.
8. INSPECT AND CLEAN VALVE SEATS (a) Using a 455 carbide cutter, resurface the valve seats.
Remove only enough metal to clean the seats.
(b) Check the valve seating position.
Apply a thin coat of prussian blue (or white lead) to the valve
face. Lightly press the valve against the seat. Do not rotate
the valve.
(c) Check the valve face and seat for the following:w If blue appears 3605 around the face, the valve is
concentric. If not, replace the valve.
w If blue appears 3605 around the valve seat, the
guide and face are concentric. If not, resurface the
seat.
w Check that the seat contact is on the middle of the
valve face with the following width:
1.0±1.4 mm (0.039±0.055 in.)
If not, correct the valve seats as follows:
(1) If the seating is too high on the valve face, use 30 5
and 45 5 cutters to correct the seat.
±
ENGINE MECHANICAL Cylinder HeadsEM±83
WhereEverybodyKnowsYourName

16. IF NECESSARY, REPLACE SPARK PLUG TUBEGASKETS
(a) Bend the ventilation case claw installed on the cylinderhead cover to an angle of 905 or more.
(b) Using SST and a hammer, tap out the gasket.
SST 09550±10012 (09552±10010, 09560±10010)
(c) Using SST and a hammer, tap in a new gasket until its surface is flush with the upper edge of the cylinder head
cover.
SST 09550±10012 (09552±10010, 09560±10010)
(d) Apply a light coat of MP grease to the gasket lip.
(e) Return the ventilation case claw to its original position.
ASSEMBLY OF CYLINDER HEADS
(See Components on page EM±59)
HINT:
w Thoroughly clean all parts to be assembled.
w Before installing the parts, apply new engine oil to all
sliding and rotating surfaces.
w Replace all gaskets and oil seals with new ones.
1. INSTALL SPARK PLUG TUBES HINT: When using a new cylinder head, spark plug tubes
must be installed.
(a) Apply adhesive to the end of the spark plug tube.
Adhesive: Part No.08833±00070, THREE BOND 1324
or equivalent
(b) Using a wooden block and hammer, tap in a new sparkplug tube until there is 48.7±49.3 mm (1.917 ±1.941 in.)
protruding from the camshaft bearing cap installation
surface of the cylinder head.
NOTICE: Avoid tapping a new spark plug tube in too far
by measuring the amount of protrusion while tapping.
±
ENGINE MECHANICAL Cylinder HeadsEM±89
WhereEverybodyKnowsYourName

2. INSTALL VALVES(a) Using SST, push in a new oil seal.
SST 09201±41020
(b) Install the following parts:(1) Valve
(2) Spring seat
(3) Valve spring
(4) Spring retainer
(c) Using SST, compress the valve spring and place the two
keepers around the valve stem.
SST 09202±70010
(d) Using a plastic±faced hammer, lightly tap the valve stem
tip to assure proper fit.
3. INSTALL VALVE LIFTERS AND SHIMS Check the valve lifter rotates smoothly by hand.
EM±90
±
ENGINE MECHANICAL Cylinder Heads
WhereEverybodyKnowsYourName