Yanmar 3YM30, Service Manual

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