67
Disassembly/Inspection and Service
22 690 01 Rev. --
KohlerEngines.com
Inspection and Service
Valve Details
INTAKE VALVE
EXHAUST VALVE
A
A
D
F
G
G
D
F
H
C
C
A
A
B
B
E
E
H
Dimension
Intake
Exhaust
A
Seat Angle
44.5°
44.5°
B
Insert O.D.
40.094/40.11 mm (1.578/1.579 in.)
35.094/35.11 mm (1.381/1.382 in.)
C
Guide Depth
11.85/12.25 mm (0.466/0.482 in.)
10.80/11.20 mm (0.425/0.440 in.)
D
Guide I.D.
6.038/6.058 mm (0.2377/0.2385 in.)
6.038/6.058 mm (0.2377/0.2385 in.)
E
Valve Head Diameter
35.875/36.125 mm (1.412/1.422 in.)
32.875/33.125 mm (1.294/1.304 in.)
F
Valve Face Angle
45°
45°
G
Valve Margin (Min.)
0.5 mm (0.0196 in.)
1.0 mm (0.0393 in.)
H
Valve Stem Diameter
5.982/6.000 mm (0.2355/0.2362 in.)
5.970/5.988 mm (0.2350/0.2357 in.)
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 0.076 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 0.038/0.076
mm (0.0015/0.0030 in.) or exhaust clearance exceeds 0.050/0.088 mm (0.0020/0.0035 in.), determine whether valve
stem or guide is responsible for excessive clearance.
Maximum (I.D.) wear on intake valve guide is 6.135 mm (0.2415 in.) while 6.160 mm (0.2425 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.
