Nanni N4.40, Workshop Manual

Page: 147 / 175

ENGINE
03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM
1-S77
Clearance between Valve Stem and Valve Guide
1. Remove carbon from the valve guide section.
2. Measure the valve stem O.D. with an external micrometer.
3. Measure the valve guide I.D. with a small hole gauge, and
calculate the clearance.
4. If the clearance is more than the allowable limit, replace the
valves.
5. If the clearance stays more than the allowable limit, replace the
valve guide also.
M00000003ENS0109US1
Replacement of Valve Guide
(When removing)
1. Press out the used valve guide with the valve guide replacing
tool. (See page "SPECIAL TOOLS" .)
(When installing)
1. Clean the new valve guide and valve guide bore, and apply
engine oil to them.
2. Press fit the new valve guide with the valve guide replacing tool.
3. Ream accurately the I.D. of the valve guide to the specified
dimension.
IMPORTANT
• Do not hit the valve guide with a hammer during
replacement.
M00000003ENS0110US1
Clearance between
valve stem and valve
guide
Factory spec.
0.040 to 0.070 mm
0.0016 to 0.0027 in.
Allowable limit
0.10 mm
0.0039 in.
Valve stem O.D. Factory spec.
7.960 to 7.975 mm
0.3134 to 0.3139 in.
Valve guide I.D. Factory spec.
8.015 to 8.030 mm
0.3156 to 0.3161 in.
Valve guide I.D.
(Intake and exhaust)
Factory spec.
8.015 to 8.030 mm
0.3156 to 0.3161 in.
(A) When Removing (B) When Installing
KiSC issued 06, 2009 A