Detroit Diesel 4000 Series, Service Manual, Page: 536 / 2706

SERIES 4000 12/16V SERVICE MANUAL
[b] Replace piston if damage is more extensive, i.e., if scoring or pitting extends as far as
the first piston groove (1). See Figure 285.
1. First Piston Groove
Figure 285 Checking Piston Skirt and Top Land
5. Inspect piston for extensive polishing wear on piston skirt (appears dull rather than shiny)
and concentrated scoring.
[a] If piston skirt shows extensive polishing wear or concentrated scoring, replace the
piston.
[b] If piston skirt does not show extensive polishing wear or concentrated scoring,
continue inspection.
6. Inspect piston skirt for minor, localized scuffing.
[a] If piston skirt shows localized scuffing, replace piston.
[b] If piston skirt does not show localized scuffing, continue inspection.
Checking Piston Crown
Perform the following steps to inspect and repair the piston crown.
All information subject to change without notice.
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