1
Piston ring spreading tool
4
Connecting rod
2
Piston ring
5
Piston
3
Connecting rod bearing cap
Figure 84. Piston ring removal.
(3) If the feeler gage slides in at any point between the piston ring and piston land, clearance is at or over the
allowable maximum, and the piston must be replaced.
(4) If the feeler gage fails to slide between the piston ring and piston land, clearance is below the allowable
minimum. Reduce the thickness of the piston ring by lapping it on a sheet of No. 000 emery cloth. Place
the emery cloth on a perfectly flat surface and make sure that the pressure on the ring is the same at all
points.
(5) Replace any piston ring which is sprung out of its natural shape or permanently distorted.
h. Piston Skirt to Sleeve Clearance.
(1) Before measuring the clearance between the piston skirt and cylinder sleeve, note that the piston skirt fits
closer than the piston ring lands. Always check the piston skirt clearance, not the piston land clearance.
(2) Use a micrometer on the piston to make sure that it is perfectly round. Replace the piston if it is out-of-
round beyond the wear limits.
(3) Select two pieces of 1/2-inch wide feeler stock 10 inches long and totaling 0.002 inch in thickness. Do not
use a single feeler strip, because it is too stiff and will not conform to the curve of the cylinder sleeve bore.
(4) Attach the feeler stock to an accurate spring scale.
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