Nanni N4.40, Workshop Manual

Page: 149 / 175

ENGINE
03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM
1-S79
Correction of Valve and Valve Seat
NOTE
• Before you correct the valve and seat, examine the valve
stem and measure the I.D. of the valve guide section.
Repair them if necessary.
• After you correct the valve seat, be sure to examine the
valve recessing.
1) Correction of valve
1. Correct the valve with a valve refacer.
[D1503-M, D1703-M, D1803-M, V2003-M, V2203-M, V2403-M,
V2403-M-T, D1703-M-BG, V2003-M-BG, V2003-M-T-BG,
V2203-M-BG, V2403-M-BG]
[D1803-M-DI, V2403-M-DI, V2403-M-DI-T]
2) Correction of valve seat
1. Slightly correct the seat surface with a 1.0 rad (60 °) or 0.79 rad
(45 °) valve seat cutter.
2. Correct the seat surface with a 0.52 rad (30 °) or 0.26 rad (15 °)
valve seat cutter. The width must be near the specified valve
seat width (2.12 mm, 0.0835 in.).
3. After you correct the seat, examine that the valve seating is flat.
Apply a thin layer of compound between the valve face and
valve seat, and lap them with a valve lapping tool.
4. Examine the valve seating with Prussian Blue. The valve
seating surface must show good contact on all sides.
[D1503-M, D1703-M, D1803-M, V2003-M, V2203-M, V2403-M,
V2403-M-T, D1703-M-BG, V2003-M-BG, V2003-M-T-BG,
V2203-M-BG, V2403-M-BG]
[D1803-M-DI, V2403-M-DI, V2403-M-DI-T]
M00000003ENS0112US1
Valve face angle
Factory
spec.
Intake
1.0 rad
60 °
Exhaust
0.79 rad
45 °
Valve face angle
Factory
spec.
Intake
0.79 rad
45 °
Exhaust
0.79 rad
45 °
Valve seat angle
Factory
spec.
Intake
1.0 rad
60 °
Exhaust
0.79 rad
45 °
Valve seat angle
Factory
spec.
Intake
0.79 rad
45 °
Exhaust
0.79 rad
45 °
(1) Valve Seat Width
(2) Identical Dimensions (A) Examine the Contact
(B) Correct Seat Width
(C) Examine the Contact
(a) 0.26 rad (15 °) or 0.52 rad (30 °)
(b) 0.79 rad (45 °) or 1.0 rad (60 °)
(c) 0.52 rad (30 °) or 0.26 rad (15 °)
KiSC issued 06, 2009 A