Nanni N4.40, Workshop Manual

Page: 150 / 175

E N G IN E
03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM
1-S80
Valve Lapping
1. Apply the compound equally to the valve lapping surface.
2. Put the valve into the valve guide. Lap the valve on its seat with
a valve lapping tool.
3. After you lap the valve, clean away the compound and apply oil,
then lap the valve again with oil.
4. Apply Prussian Blue to the contact surface to measure the
seated rate.
5. If the seated rate is less than 70 %, lap the valve again.
IMPORTANT
• After you complete the valve lapping and assemble the
valve, examine the valve recessing and adjust the valve
clearance.
M00000003ENS0113US1
Free Length and Tilt of Valve Spring
1. Measure the free length (B) of valve spring with a vernier
calipers.
2. If the measurement is less than the allowable limit, replace it.
3. Put the valve spring on a surface plate, and put a square on the
side of the valve spring.
4. Make sure that the full side is in contact with the square.
5. Turn the valve spring to measure the maximum tilt
(A) .
6. If the measurement is more than the allowable limit, replace it.
7. Examine the full surface of the valve spring for scratches.
8. If there is a defect, replace it.
M00000003ENS0114US1
Setting Load of Valve Spring
1. Put the valve spring on a tester.
2. Compress the valve spring to the specified setting length.
3. Read the compression load on the gauge.
4. If the measurement is less than the allowable limit, replace the
valve spring.
M00000003ENS0115US1
Tilt (A) Allowable limit
1.0 mm
0.039 in.
Free length (B)
Factory spec.
41.7 to 42.2 mm
1.65 to 1.66 in.
Allowable limit
41.2 mm
1.62 in.
(A) Tilt (B) Free Length
Setting load /
Setting length
Factory spec.
118 N / 35.0 mm
12.0 kgf / 35.0 mm
26.5 lbf / 1.38 in.
Allowable limit
100 N / 35.0 mm
10.2 kgf / 35.0 mm
22.5 lbf / 1.38 in.
KiSC issued 06, 2009 A