Engine Body; Cylinder Head - Yanmar 3YM30 Sevice Manual

13. Service standards

13.2 Engine body

13.2.1 Cylinder head

(1) Cylinder head
Inspection item
Combustion surface distortion
Valve sink
Seat angle
Valve seat
(2) Intake/exhaust valve and guide
Inspection item
Intake Guide inside diameter
Valve stem outside diameter
Clearance
Exhaust Guide inside diameter
Valve stem outside diameter
Clearance
Valve guide projection from cylinder head
Valve guide driving-in method
(3) Valve spring
Inspection item
Free length
Inclination
(4) Rocker arm and shaft
Inspection item
Arm shaft hole diameter
Shaft outside diameter
Clearance
Standard
mm 0.05 or less
Intake
mm Exhaust
Intake
deg.
Exhaust
Standard
6.000-6.012
5.960-5.975
0.025-0.052
6.000-6.012
5.945-5.960
0.040-0.067
Cold-fitted
Standard
Standard
12.000-12.020
11.966-11.984
0.016-0.054
202
Limit
0.15
0.4-0.6 0.8
120 -
90 -
Limit
6.08
5.90
0.16
6.08
5.90
0.17
9.8-10.0 -
-
Limit
37.8 36.3
- 1.3
Limit
12.07
11.94
0.13
Reference
page
5.2.1(1)
5.2.3(3)
5.2.1(3)
mm
Reference
page
5.2.3
5.2.3(4)
mm
Reference
page
5.2.4(1)
mm
Reference
page
5.2.7(1)