Toyota 4Y 2006 Manual page 98

Point Operations
[Point I ]
Disassembly:
Evenly loosen the support set bolts in two or three times,
following the order shown in the illustration.
[Point 21
Inspection:
Inspect for wear or damage to the contact surface for the
rocker arm valve stem cap.
If there is a slight damage, correct it by polishing with oil stone,
and replace if there is a considerable wear or damage.
Inspection:
Move the rocker arm as shown in the illustration, and inspect
the clearance between the rocker arm and the shaft. If the
clearance is large, disassemble and inspect it.
Inspection:
Inspect the oil clearance between the rocker arm and the
rocker shaft.
1.
Measure the rocker arm inside diameter with a caliper gauge.
Standard: 18.500 to 18.515 mm (0.7283 to 0.7289 in.)
Measure the rocker shaft outside diameter with a micrometer.
Standard: 18.474 to 18.487 mm (0.7273 to 0.7278 in.)
Calculate the oil clearance by the difference between the arm
inner diameter and the shaft outer diameter.
Standard: 0.013 to 0.041 mm (0.0005 to 0.0016 in.)
Limit: 0.08 mm (0.0031 in.)
If it exceeds the limit, replace the rocker arm or the rocker
shaft.