Detroit Diesel 4000 Series, Service Manual, Page: 544 / 2706

SERIES 4000 12/16V SERVICE MANUAL
[b] If piston rings are not damaged, continue with inspection.
Condition or wear of chrome layer (1) is a deciding factor when reusing or replacing fire
ring (2), compression ring (3) and oil control ring (4). See Figure 292.
1. Chrome Layer 3. Compression Ring
2. Fire Ring 4. Oil Control Ring
Figure 292 Inspecting Piston Rings
3. Inspect chrome layer for scoring, cracks or heat discoloration.
[a] If scoring, cracks or heat discoloration is found, replace piston rings.
[b] If piston rings are not scored, cracked or no heat discoloration is found, continue
with inspection.
4. Inspect piston rings for sharp edges.
[a] Replace sharp-edged piston rings.
[b] If piston rings are not sharp-edged, continue with inspection.
5. Inspect upper edge of rectangular section ring for sharp edge.
[a] If upper edge of rectangular section ring is sharp-edged, replace ring.
[b] If upper edge of rectangular section ring is not sharp-edged, continue with inspection.
6. Visually check oil slits of control ring for clogged or carbon deposit areas.
[a] If oil slits of oil control ring are clogged with carbon, remove carbon deposits.
[b] If oil slits of control ring are not clogged with carbon, continue inspection.
All information subject to change without notice.
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