Yanmar 4TNV98, Service Manual

Page: 68 / 246

4TNV98 & 4TNE98 Diesel Engine Section 3. Engine 66
Introduction
This section of the Service Manual describes
servicing of the engine.
Cylinder Head Specifications
Adjustment Specifications
Model Valve Clearance
Valve Bridge Clearance
(4-Valve Head Only)
4TNV98
0.006 - 0.010 in.
(0.15 - 0.25 mm)
0
4TNE98
0.006 - 0.010 in.
(0.15 - 0.25 mm)
-
Cylinder Head
4TNV98 Engine
Inspection Item Standard Limit
Reference
Page
Combustion Surface Distortion (Flatness)
0.0020 in.
(0.05 mm) or less
0.0059 in.
(0.15 mm)
Valve Recession
4TNV98
(4-Valve Head)
Intake
Exhaust
0.0142 - 0.0220 in.
(0.36 - 0.56 mm)
0.0138 - 0.0217 in.
(0.35 - 0.55 mm)
0.0315 in.
(0.8 mm)
0.0315 in.
(0.8 mm)
See Valve
Recession
on
Page 95
and 98.
Intake 120° -
Seat Angle
Exhaust 90° -
Valve Seat
(4-Valve)
Seat Correction Angle 40°, 150° -
See Valve
Face and
Valve Seat
on
Page 96
and 99.
4TNE98 Engine
Inspection Item Standard Limit
Reference
Page
Combustion Surface Distortion (Flatness)
0.0020 in.
(0.05 mm) or less
0.0059 in.
(0.15 mm)
See
Inspection
of Cylinder
Head on
page 94.
Intake 0.020 - 0.028 in.
(0.5 - 0.7 mm)
0.039 in.
(1.0 mm)
Valve Sink
Exhaust
0.024 - 0.032 in.
(0.6 - 0.8 mm)
0.043 in.
(1.1 mm)
Intake 120° -
Valve Seat Angle
Exhaust 90° -
See
Inspection
of Intake
and
Exhaust
Valves on
page 95.