45
Disassembly/Inspection and Service
14 690 12 Rev. -- KohlerEngines.com
Inspection and Service
Valve Details
F
G
E
A
A
E
D
F
G
BB
C
C
D
A
A
Dimension Intake Exhaust
A Seat Angle
44.5° 44.5°
B Guide Depth 22.6 mm 20.5 mm
C Guide I.D. 5.500/5.512 mm 5.500/5.512 mm
D Valve Head Diameter 25.875/26.125 mm 23.875/24.125 mm
E Valve Face Angle
45° 45°
F Valve Margin (Min.) 0.80 mm 0.80 mm
G Valve Stem Diameter 5.465/5.480 mm 5.465/5.480 mm
After cleaning, check fl atness of cylinder head and
corresponding top surface of crankcase, using a
surface plate or precision straight edge and feeler
gauge. Maximum allowable out of fl atness is 0.08 mm
(0.003 in.).
Carefully inspect valve mechanism parts. Inspect valve
springs and related hardware for excessive wear or
distortion. Check valves and valve seats for evidence of
deep pitting, cracks, or distortion.
Check running clearance between valve stems and
guides.
Hard starting, or loss of power accompanied by high
fuel consumption, may be symptoms of faulty valves.
Although these symptoms could also be attributed to
worn rings, remove and check valves fi rst. After removal,
clean valve heads, faces, and stems with a power wire
brush. Then, carefully inspect each valve for defects
such as warped head, excessive corrosion, or worn stem
end. Replace valves found to be in bad condition.
Valve Guides
If a valve guide is worn beyond specifi cations, it will not
guide valve in a straight line. This may result in burned
valve faces or seats, loss of compression, and excessive
oil consumption.
To check valve guide-to-valve stem clearance,
thoroughly clean valve guide and, using a split-ball
gauge, measure inside diameter. Then, using an outside
micrometer, measure diameter of valve stem at several
points on stem where it moves in valve guide. Use
largest stem diameter to calculate clearance. If intake
clearance exceeds 0.047 mm (0.0018 in.) or exhaust
clearance exceeds 0.082 mm (0.0032 in.), determine
whether valve stem or guide is responsible for excessive
clearance.
Maximum (I.D.) wear on intake valve guide is 5.512 mm
(0.2170 in.), while 5.512 mm (0.2170 in.) is maximum
allowed on exhaust guide. Guides are not removable. If
guides are within limits but valve stems are worn beyond
limits, replace valves.
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