Cylinder Liner; Cylinder Liner - Endoscopic Examination - MTU 12 V 4000 G23 Technical Documentation Manual

98
6.2

Cylinder Liner

6.2.1 Cylinder liner – Endoscopic examination
Preconditions
• Engine is stopped and starting disabled.
Special tools
Designation / Use
Rigid endoscope
Preparatory steps
1. Remove cylinder-head cover (→ Page 108).
2. Remove injector (→ Page 110).
Positioning crankshaft at BDC
1. Using barring device, turn crankshaft until crankpin of the cylinder to be tested has reached BDC.
2. Insert endoscope into cylinder liner through injector seat.

Cylinder liner - Endoscopic examination

Findings
• Thin carbon coating on carbon scraper ring
• Slight localized additive deposits at top edge
• Localized smooth areas at lower edge
• Carbon deposits on entire circumference between top piston ring and
lower edge of carbon scraper ring
• First signs of marks left by top piston ring
• Bright mark on entire circumference
• Faultless, even honing pattern
• First signs of marks left by lower cooling bores
• Running pattern seems darker
• Darker areas of even or varying color intensity
• Beginning and end of the discoloration are not sharply defined and do
not cover the entire stroke area
• Dark areas in the upper section of the cooling bore, remaining
circumference cannot be faulted
• Piston rings cannot be faulted
• On the entire circumference not only bright discoloration (not critical for
operation) clearly visible darker stripes that begin at the top piston ring
• Heat discoloration in the direction of stroke and honing pattern damage
• Heat discoloration of piston rings
1. Compile endoscopy report using the table.
2. Use technical terms for description of the liner surface (→ Page 100).
3. Depending on findings:
• Do not take any action or
• carry out further endoscopic examination as part of maintenance work or
• contact Service: cylinder liner must be replaced.
M015710/01E 07-02
Task Description
Part No.
Y20097353
Task
No actions required
Further endoscopic examination
required as part of maintenance
work
Cylinder liner must be replaced;
Service must be contacted
Qty.
1
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