Doosan GL08K - Page 82

Maintenance - 76 -
3) Piston inspection
a) Visual check
Replace the piston rings with new ones if detected worn or broken when the engine is overhauled.
b) Piston ring gap
 Insert the piston ring into the
upper portion of the cylinder liner
bore so that it is held at a right
figure to the cylinder liner wall.
 Measure the piston ring gap with a
feeler gauge.
 Replace piston rings with new
ones if the gap is beyond the limit
c) Piston ring side clearance
 Fit the compression ring and oil
ring in the piston ring groove.
 With a feeler gauge, measure side
clearance of each ring, and
replace either the ring or piston if
the measured value is beyond the
specified limit.
d) Piston ring tension
 With a tension tester, measure piston ring tension.
 Replace the piston ring if the measured value is beyond the limit.
Feeler gauge
EA0M4033
Standard Limit
Top ring 0.40 ~ 0.60 mm 1.5 mm
2nd ring 0.8 ~ 0.95 mm 1.5 mm
Oil ring 0.30 ~ 0.50 mm 1.5 mm
EA0M4032
Feeler
gauge
Standard Limit
Top ring - -
2nd ring
0.07 ~
0.102 mm
0.15
mm
Oil ring
0.05 ~
0.085 mm
0.15
mm
Standard
Top ring 2.58 ~ 3.88 kg
2nd ring 1.81 ~ 2.71 kg
Oil ring 3.57 ~ 5.03 kg