Geko 12V 4000 G 41, Operating Instructions Manual

Page: 61 / 124

Cylinder Liner 3
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, max. diameter: 7 mm TC
Preparatory steps
1. Remove cylinder-head cover ( Page 6 12).
2. Remove injector ( Page 6 15).
Bringing the piston to BDC position
1. Use the barring tool to rotate the crankshaft until the crank pin of the cylinder to be inspected is at BDC position.
2. Insert the endoscope through the cylinder-head injector bore into the combustion chamber.
Findings Task
Thin carbon deposits around the carbon-residue control ring
Light, localized additive deposits on upper surface
Polished spots on lower edge
Ring of oil deposits in the area between the positions of the upper
piston-ring and the lower edge of the carbon-residue control ring
Start of traces left by upper piston ring
Bright surface round circumference
Even honing pattern without complaint
Start of traces left by lower cooling-oil bores
Wear pattern appears to be darker
No measures necessary.
Oxidation discoloration of even or uneven intensity.
Start and end of discolored areas have no clear edges and do not
extend over the whole stroke length
Discolored areas become lighter in upper part of cooling bore; rest of
circumference without complaint
Piston-ring set without complaint
Further endoscope check
necessary during maintenance
work.
In addition to bright discolorations (which are not critical for engine
operation), evidently darker "black zones" all over the running surface,
beginning at upper-piston-ring TDC position
Overheating discoloration in piston stroke direction with damaged
honing pattern
Piston rings show overheating discoloration
Cylinder liner must be replaced.
Contact Service.
Cylinder-liner endoscopic examination
1. Assess findings of endoscopic examination using the above table.
2. For description of findindings on cylinder liner surface use the specified terms ( Page 6 5).
3. Depending on the findings:
Do not take any measures, or
Conduct endoscopic examination of another liner in the course of maintenance work; or
Contact Service: Cylinder liner must be replaced.
M015403/00E 02-09 © MTU
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