Teledyne Continental Motors, Inc.
TM
Maintenance
Inspections
3.
Position the piston at bottom dead center on the power stroke. The exhaust valve will
be open with the piston in this position.
4.
Insert the borescope probe through the upper spark plug hole and inspect the internal
surfaces of each cylinder, including the exhaust valve and exhaust valve seat. Use
IOF-240 Series Engine Maintenance Manual
7-27
31 August 2007
Change 1
Table 7-5 and Figure 7-8 through Figure 7-14 to interpret inspection findings.
5.
Position the piston at bottom dead center on the intake stroke.
6.
Insert the borescope probe through the upper spark plug hole and inspect the intake
valve and valve seat of each cylinder. Use Table 7-5 and Figure 7-8 through Figure 7-
14 to interpret inspection findings.
7.
Continue turning the crankshaft and inspecting each cylinder on the intake and
exhaust strokes until all cylinders have been inspected.
Table 7-5.
Borescope Inspection Objectives and Corrective Action Table
Item
Objective
If Abnormality Noted
Combustion
Chamber
Inspect:
Valve seat inserts for erosion, burning
Remove cylinder for repair
Sparkplug heli-coils for protrusion into combustion
chamber
Heavy carbon deposits/presence of excessive oil
Exhaust
Valve Face
Inspect for signs of leakage or damage indicated by:
•
Localized discoloration on the valve face
circumference (
Repair or replace cylinder
•
Minute cracks
•
Erosion (missing material)
Intake Valve
Face
Inspect for signs of leakage or damage indicated by:
Repair or replace cylinder
•
Localized discoloration on the valve face
circumference
•
Erosion (missing material)
Inspect exposed surface of bore for:
•
Heavy scoring/piston rub (Figure 7-12)
•
Piston pin rub (wide band pattern in horizontal
plane at 3 o’clock and/or 9 o’clock position)
1
Repair or replace cylinder
Cylinder Bore
•
Corrosion (Figure 7-11)
Remove cylinder for repair
Excessive oil in cylinder/heavy deposits of carbon in
combustion chamber
Normal indication for in service
cylinders
Upper portion of cylinder bore has no visible hone
pattern (Figure 7-13 and Figure 7-14)
Piston Head
Inspect for:
Remove cylinder for repair
•
Piston crown for erosion, missing material
•
Visible damage from foreign debris
1
Remove cylinder for repair or replacement. Perform complete inspection of connecting rod bushing for
correct installation and finishing.
