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ENGINE TOP E ND 4-9
Piston Ring, Piston Ring Groove Inspectio n
Visually inspect the piston rings and the piston ring
If the rings are worn unevenly or damaged, they must be
If the piston ring grooves are worn unevenly or damaged,
the piston must be replaced and fitted with new rings.
Check for uneven groove wear by inspecting the ring seat-
The rings should fit perfectly parallel to the groove sur-
faces. If not, the piston must be replaced.
With the piston ring in its groove, make several mea-
surements w ith a thickness gauge [A] to determine piston
If the clearance exceeds the s ervice limit, measure the
thickness of the piston ring
If the ring has worn down to less than the service limit,
replace the ring; if the groove width exceeds the service
limit, replace the piston.
Piston Ring/Groove Clearance (Top, Second)
0.02 ∼ 0.06 mm
Piston Ring Thickness (Top, Second)
0.97 ∼ 0.99 mm
Piston Ring Groove Width (Top, Second)
1.01 ∼ 1.03 mm
Piston Ring End Gap Inspection
Place the piston ring [A] inside the cylinder [B], using the
piston to locate the ring squarely in place.
Set it close to the bottom of the cylinder, where cylinder
wear is low.
Measure the gap [C] between the ends of the ring with a
If the gap is wider than the service limit, the ring is over-
worn and must be replaced.
Piston Ring End Gap (Top, Second)
0.15 ∼ 0.35 mm