IO-390-D Series Engine Maintenance Manual
© 2020 Avco Corporation. All Rights Reserved
72-30
March 2020
Page 215
IO-390-D Series Engine Maintenance Manual
Piston Inspection Checklist (Cont.)
Figure 21
Checking Piston Ring Side Clearance
Inspection Item
Findings/Corrective Action
Cylinder 1 Cylinder 2 Cylinder 3 Cylinder 4
Measure the side
clearance between the
piston rings and
piston with a feeler
gauge and straight
edge (Figure 21).
Top
compression
piston ring
Actual
Measurement**
SSP-1776
Second
compression
piston ring
Actual
Measurement**
SSP-1776
Oil regulating
piston
expander ring
Actual
Measurement**
SSP-1776
Measure the piston
ring end-gap with
feeler gauges.
Complete the “Piston
Ring End-Gap
Check” in this
chapter.
Top
compression
piston ring
Actual
Measurement**
SSP-1776
Second
compression
piston ring
Actual
Measurement**
SSP-1776
Oil regulating
piston
expander ring
Actual
Measurement**
SSP-1776
**Compare the actual measurement against the limits in the latest revision of the
Service Table of Limits
- SSP-177
6. Replace the piston if any of the measurements are out of tolerance.