695578
Piston and Rings
Use extreme care when handling
piston. Any scratches, gouges or
other marks could score the cylinder during
operation and result in engine damage.
1.
Before removing piston, clean any carbon from the
top of the cylinder bore to prevent ring breakage
when removing the piston.
2.
Push the rod and piston out through the top of the
cylinder.
Oversize pistons are identified by the size imprinted on
the piston as shown.
3.
Check the piston for wear by measuring at the
bottom of the skirt 90
o
from the wrist pin hole.
4.
Clean the carbon from the piston ring grooves,
install new rings and measure side clearance.
NOTE
Tolerances are listed in the table of specifications.
Always use new piston rings
when servicing piston. When
reused, old piston rings may weaken, break or
dislodge resulting in engine damage.
5.
Replace rings in sets and always stagger ring
gaps.
6.
When installing new rings, deglaze cylinder wall,
using a commercially available deglazing tool.
7.
Use a ring expander to remove and replace rings.
Do not spread the piston rings
too wide. Doing so may result in
ring breakage.
The top compression ring will have a chamfer on the
inside edge.
NOTE
The top compression ring must be installed with the cham-
fer side up.
8.
To check ring end gap, place ring squarely in
center of ring travel area.
9.
Use the piston to push the ring down into the
cylinder at least one inch.
10. Check ring gap on new ring to determine if cylinder
should be rebored to take oversize parts.
11. See Table of Specifications.
Chapter 8
Piston, Rings and Connecting Rods
Piston measurements are taken at bottom of skirt 90
0
from wrist pin hole
Indicates .010 (.254 mm)
Oversize Piston
1st Compression Ring
Side Clearance
2nd Compression Ring
3rd Oil Control Ring
.010
(2.54 mm)
Piston
Cylinder
Piston Ring
Barrel Faced Top Ring
Scraper Ring
Oil Control Ring
NOTE
Emission Compliant VLV uses this
ring package.
8-1
CAUTION
CAUTION
CAUTION
