1991 LEXUS SC400 engine

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Page 1784 of 4087

LEXUS SC400 1991  Service Repair Manual 
(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 i

Page 1785 of 4087

LEXUS SC400 1991  Service Repair Manual 
(2) If the seating is too low on the valve face, use 755
and 45 5 cutters to correct the seat.
(d)  Hand±lap  the valve and valve seat with an abrasive compound.
(e)  After hand±lapping, clean the

Page 1786 of 4087

LEXUS SC400 1991  Service Repair Manual 
10.  INSPECT CAMSHAFTS AND BEARINGS
A. Inspect camshaft for runout(a)  Place the camshaft on V±blocks.
(b)  Using a dial indicator, measure the circle runout at thecenter journal.
Maximum circle run

Page 1787 of 4087

LEXUS SC400 1991  Service Repair Manual 
E. Inspect camshaft gear springUsing a vernier caliper, measure the free distance between
the spring ends.
Free distance: 18.2±18.8 mm (0.712±0.740 in.)
If the free distance is not as specified, re

Page 1788 of 4087

LEXUS SC400 1991  Service Repair Manual 
G. Inspect camshaft thrust clearance(a)  Install the camshafts.(See step 7 on pages  EM±95 to 101)
(b)  Using a dial indicator, measure the thrust clearance
while moving the camshaft back and forth.

Page 1789 of 4087

LEXUS SC400 1991  Service Repair Manual 
12.  INSPECT AIR INTAKE CHAMBERUsing 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 g

Page 1790 of 4087

LEXUS SC400 1991  Service Repair Manual 
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.
S

Page 1791 of 4087

LEXUS SC400 1991  Service Repair Manual 
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