MTU 20 V 4000 G23, Technical Publication

Page: 101 / 178

96 Task Description
6.2 Cylinder Liner
6.2.1 Cylinder liner – Endoscopic examination
Preconditions
• Engine is stopped and starting disabled.
Special tools
Designation / Use Part No. Qty.
Rigid endoscope Y20097353 1
Preparatory steps
1. Remove cylinder-head cover ( → Page 105).
2. Remove injector ( → Page 107).
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 Task
• 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
No actions required
• 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
Further endoscopic examination
required as part of maintenance
work
• 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
Cylinder liner must be replaced;
Service must be contacted
1. Compile endoscopy report using the table.
2. Use technical terms for description of the liner surface (
→ Page 97).
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.
Final steps
1. Install injector ( → Page 107).
2. Install cylinder-head cover ( → Page 105).
M015715/00E 06-08 © MTU