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ENGINE TOP END 5-23
Valves
Valve Guide Installation
•
Apply oil to the valve guide outer surface before i nstalla-
tion.
•
Heat the area around the valve guide hole to about 120 ∼
150 °C (248 ∼ 302 °F).
•
Drive the valve guide in from the t op of the head using the
valve guide arbor. The flange stops the guide from going
in too far.
Spec
ial Tool -
Valv
e G uide A rbor,
4.5: 57001–1331
•
Wait until the cylinder head cools down and then ream the
valve guide with the valve guide reamer [A] even if the old
guide is reused.
○
Turn the reamer in a clockwise direction until the reamer
turns freely in the guide. Never turn the reamer counter-
clockwise or it will be dulled.
○
Once the guides are reamed they must be cleaned thor-
oughly.
Special Tool - Valve Guide Reamer, 4.5: 57001–1333
V
alve-to-Guide Clearance Measurement (Wobble
Method)
If a small bore gauge is not available, inspect the valve
g
uide wear by measuring the valve to valve guide clearance
with the wobble method as indicated below.
•
Insert a new valve [A] into the guide [B] and set a dial
gauge against the stem perpendicular to it as close as
possible to the cylinder head mating surface.
•
Move the stem back and forth [C] to measure valve/valve
guide clearance.
•
Repeat the measurement in a direction at a right angle to
the first.
If the reading exceeds the service limit, replace the guide.
NOTE
○
The reading is not actual valve/valve guide clearance
because the measuring point is above the guide.
Valve/Valve Guide Clearance (Wobble Method)
Inlet Exhaust
Standard:
0.03 ∼ 0.12 mm 0.09 ∼ 0.18 mm
(0.0012 ∼ 0.0047 in.) (0.0035 ∼ 0.0071 in.)
Service
0.33 mm 0.40 mm
Limit:
(0.013 in.) (0.016 in.)