Service and Repairs

77
Disassembly/Inspection and Service
17 690 01 Rev. L KohlerEngines.com
Valve Details
A
E
D
D
B
C
D
CH245/CH255 Valve Specifi cations
Item Dimension Intake Exhaust
A Head Diameter
24.875-25.125 mm
(0.9793-0.9892 in.)
23.8-24.2 mm
(0.9370-0.9527 in.)
B Valve Length 64 mm (2.5196 in.) 64 mm (2.5196 in.)
C Stem Diameter 5.474 mm (0.2155 in.) 5.464 mm (0.2151 in.)
D Face/Seat Width - Maximum 2.0 mm (0.079 in.) 2.0 mm (0.079 in.)
E Face/Seat Angle 89.5°-90.5° 89.5°-90.5°
CH260/CH270 Valve Specifi cations
Item Dimension Intake Exhaust
A Head Diameter
26.875-27.125 mm
(1.0581-1.0679 in.)
24.875-25.125 mm
(0.9793-0.9892 in.)
B Valve Length 63.3-63.9 mm (2.4921-2.5157) 63.3-63.9 mm (2.4921-2.5157)
C Stem Diameter 5.5 mm (0.217 in.) 5.438 mm (0.214 in.)
D Face/Seat Width - Maximum 2.0 mm (0.079 in.) 2.0 mm (0.079 in.)
E Face/Seat Angle 89.5°-90.5° 89.5°-90.5°
Valve Seat Inserts
Hardened steel alloy intake and exhaust valve seat
inserts are press-fi tted into cylinder head. Inserts are
not replaceable but can be reconditioned if not too badly
pitted or distorted. If cracked or badly warped, cylinder
head should be replaced.
Recondition valve seat inserts following instructions
provided with valve seat cutter being used. Cutting
proper valve face angle, as specifi ed in Valve
Specifi cation table and proper valve seat angle (89.5°-
90°) will achieve desired 0° (1° full cut) interference
angle where maximum pressure occurs on outside
diameters of valve face and seat.
Lapping Valves
NOTE: Exhaust valves that are black in color cannot be
ground and do not require lapping.
Reground or new valves must be lapped in, to provide
proper fi t. Use a hand valve grinder with suction cup
for fi nal lapping. Lightly coat valve face with fi ne grade
of grinding compound, then rotate valve on seat with
grinder. Continue grinding until smooth surface is
obtained on seat and on valve face. Thoroughly clean
cylinder head in soap and hot water to remove all traces
of grinding compound. After drying cylinder head, apply
a light coating of SAE 10 oil to prevent rusting.
Valve Stem Seals
These engines use valve stem seals on intake and
exhaust valves.
Always use new seals when valves are removed
from cylinder head. Seals should also be replaced if
deteriorated or damaged in any way. Never reuse old
seals.