Lexus SC300 / Lexus SC400. Service manual — part 572
![](/vehicle/tus/kendre/chaul/asan.png)
G.
Inspect camshaft thrust clearance
(a) Install the camshafts.
(b) Using a dial indicator, measure the thrust clearance
while moving the camshaft back and forth.
Standard thrust clearance: 0.040–0.090 mm
(0.0016–0.0035 in.)
Maximum thrust clearance: 0.12 mm (0.0047 in.)
If the thrust clearance is greater than maximum, replace the
camshaft. If necessary, replace the bearing caps and cylin-
der head as a set.
H.
Inspect camshaft gear backlash
(a) Install
the
camshafts
without installing the exhaust
camshaft sub–gear.
(See step 7 on pages
(b) Using a dial indicator, measure the backlash.
Standard backlash: 0.020–0.200 mm
(0.0008–0.0079 in.)
Maximum backlash: 0.30 mm (0.0188 in.)
If the backlash is greater than maximum, replace the cam-
shafts.
11. INSPECT VALVE LIFTERS AND LIFTER BORES
(a) Using a caliper gauge, measure the lifter bore diameter
of the cylinder head.
Lifter bore diameter: 31.000–31.016 mm
(1.2205–1.2211 in.)
(b) Using a micrometer, measure the lifter diameter.
Lifter diameter: 30.966–30.976 mm
(1.2191–1.2195 in.)
(c) Subtract the lifter diameter measurement from the lifter
bore diameter measurement.
Standard oil clearance: 0.024–0.050 mm
(0.0009–0.0020 in.)
Maximum oil clearance: 0.07 mm (0.0028 in.)
If the oil clearance is greater than maximum, replace the lifter.
If necessary, replace the cylinder head.
–
ENGINE MECHANICAL
Cylinder Heads
EM–87
![](/vehicle/tus/kendre/chaul/rero.png)
12. INSPECT AIR INTAKE CHAMBER
Using a precision straight edge and feeler gauge, measure
the surfaces contacting the intake manifold for warpage.
Maximum warpage: 0.15 mm (0.0059 in.)
If warpage is greater than maximum, replace the chamber.
13. INSPECT
INTAKE
MANIFOLD
Using a precision straight edge and feeler gauge, measure
the surfaces contacting the cylinder head and air intake
chamber for warpage.
Maximum warpage: 0.15 mm (0.0059 in.)
If warpage is greater than maximum, replace the manifold.
14. INSPECT EXHAUST MANIFOLD
Using a precision straight edge and feeler gauge, measure
the surfaces contacting the cylinder head for warpage.
Maximum warpage: 1.00 mm (0.0394 in.)
If warpage is greater than maximum, replace the manifold.
15. INSPECT CYLINDER HEAD BOLTS
Using a vernier caliper, measure the thread outside diameter
of the bolt.
Standard outside diameter: 9.770–9.960 mm
(0.3846–0.3921 in.)
Minimum outside diameter: 9.60 mm (0.3780 in.)
If the diameter is less than minimum, replace the bolt.
EM–88
–
ENGINE MECHANICAL
Cylinder Heads
![](/vehicle/tus/kendre/chaul/kns.png)
16. IF NECESSARY, REPLACE SPARK PLUG TUBE
GASKETS
(a) Bend the ventilation case claw installed on the cylinder
head 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
HINT:
•
Thoroughly clean all parts to be assembled.
•
Before installing the parts, apply new engine oil to all
sliding and rotating surfaces.
•
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 spark
plug 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 Heads
EM–89
![](/vehicle/tus/kendre/chaul/edy.png)
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
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст