Iseki SCM49, Руководство по обслуживанию, Страница: 44 / 128

44
SERVICE MANUAL FOR SGR19 & SGR17
Fig. 3-81
Measure the gaps of each piston ring with thick-
ness gauges.
Fig. 3-82
Replace the rings whose gaps are in excess of
the usable limit.
Standard value Usable limit
No.1
compression
0.25 – 0.40 mm 1.5 mm
ring
No.2
compression
0.25 – 0.40 mm 1.5 mm
ring
Oil ring 0.25 – 0.40 mm 1.0 mm
• Inspection of piston ring clearance in ring
grooves
Fig. 3-83
Clean ring grooves using a used piston ring.
Measure the clearance at the outer circumference
with thickness gauges as shown in the figure.
Standard value Usable limit
No.1
compression
0.25 – 0.40 1.5
ring
No.2
compression
0.25 – 0.40 1.5
ring
Oil ring 0.25 – 0.40 1.0
When the clearance exceeds the usable limit,
replace both piston and rings as an assembly.
• Inspection of the piston pin
The interference between the piston pin and pis-
ton pin hole should be such that the pin can be
pushed in smoothly at room temperature.
Fig. 3-84