Detroit Diesel 4000 Series, Service Manual, Page: 534 / 2706

SERIES 4000 12/16V SERVICE MANUAL
C 037.05.08 – INSPECTION AND REPAIR
Perform the following subsections to inspect and repair piston with connecting rod.
Piston
Perform the following steps to inspect and repair piston.
NOTE:
The graphite layer on the piston skirt must not be mechanically removed or treated
with strong cleaners.
To avoid injury when using carbon-deposit remover
chemical substances,
it is essential to observe the
manufacturer’s instructions for use, safety instructions
and waste disposal specifications.
1. Treat carbon deposits on piston crown and piston ring grooves with decarbonizer.
2. Clean area of piston ring grooves with rotating brush.
3. Clean oil chamber and compression surfaces with synthetic abrasive MTH 688 (rated
grain).
4. Using the surface crack testing method with fluorescent penetrant dye, check piston
for cracks.
[a] If cracked, replace the piston.
[b] If not cracked, continue inspection.
5. Carefully inspect piston ring grooves for cracks.
[a] If cracked, replace the piston.
[b] If not cracked, continue inspection.
Checking Piston Skirt and Top Land
Perform the following steps to inspect and repair piston skirt and top land.
1. Check piston skirt surface condition for wear, pitting and scoring.
[a] If worn, pitted or scored, replace the piston.
All information subject to change without notice.
C -388
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