Kohler HD Series Service Manual page 53

Some important points to remember when servicing
piston rings:
1. Cylinder bore must be de-glazed before service ring
sets are used.
2. If cylinder bore does not need re-boring and if old
piston is within wear limits and free of score or scuff
marks, old piston may be reused.
3. Remove old rings and clean up grooves. Never
reuse old rings.
4. Before installing new rings on piston, place top 2
rings, each in turn, in its running area in cylinder
bore and check end gap. Compare ring gap to
Clearance Specifi cations.
5. After installing new compression (top and middle)
rings on piston, check piston-to-ring side clearance.
Compare clearance to Clearance Specifi cations. If
side clearance is greater than specifi ed, a new
piston must be used.
Install New Piston Rings
D
E
F
Top Compression
A
Ring
C Oil Control Ring
E Expander Ring
14 690 10 Rev. --
A
B
C
Middle Compression
B
Ring
D Top Rail
F Bottom Rail
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Disassembly/Inspection and Service
Piston Ring Orientation
E
(≥ 60°)
D
Oil Ring Expander
A
Gap
C Top Oil Rail Gap
Top Compression
E
Ring Gap
NOTE: Rings must be installed correctly. Install oil
control ring assembly (bottom groove) fi rst,
middle compression ring (center groove)
second, and top compression ring (top groove)
last. Oil control ring assembly is a three-piece
design, and consists of a top rail, expander ring,
and bottom rail.
Use a piston ring expander to install rings.
1. Oil control ring assembly (bottom groove): Install
expander fi rst then bottom rail and top rail last. Make
sure ends of expander are not overlapped. Adjust
ring gaps.
2. Middle compression ring (center groove): Install
middle compression ring using a piston ring
expander tool. Make sure identifi cation mark is up or
colored dye stripe (if contained) is left of end gap.
Adjust ring gaps.
3. Top compression ring (top groove): Install top
compression ring using a piston ring expander tool.
Make sure identifi cation mark is up or colored dye
stripe (if contained) is left of end gap. Adjust ring
gaps.
B
A
C
B Bottom Oil Rail Gap
Middle Compression
D
Ring Gap
53