Clearance Between Valve Stem And Valve Guide; Replacement Of Valve Guide - Nanni N4.40 Workshop Manual

03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM

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.
Factory spec.
Clearance between
valve stem and valve
guide
Allowable limit
Valve stem O.D. Factory spec.
Valve guide I.D. Factory spec.

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.
Valve guide I.D.
Factory spec.
(Intake and exhaust)
IMPORTANT
• Do not hit the valve guide with a hammer during
replacement.
(A) When Removing
1-S77
ENGINE
0.040 to 0.070 mm
0.0016 to 0.0027 in.
0.10 mm
0.0039 in.
7.960 to 7.975 mm
0.3134 to 0.3139 in.
8.015 to 8.030 mm
0.3156 to 0.3161 in.
M00000003ENS0109US1
8.015 to 8.030 mm
0.3156 to 0.3161 in.
(B) When Installing
M00000003ENS0110US1
KiSC issued 06, 2009 A