Alignment Dowel Inspection - Lycoming IO-390-D Series Maintenance Manual

IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
Crankshaft P/N
Crankshaft S/N
Inspection Item
Look for fatigue crack(s) or
start of crack(s) in crankshaft
bore
Look for cracks caused by heat
or brittleness
Look for inappropriate repair,
such as grinding to remove
corrosion, in or near crankshaft
bore
Look for ruptures inside the
crankshaft bore
Additional check necessary?
Comments/Notes:

7. Alignment Dowel Inspection

A. Examine the alignment dowel installed in the end of the crankshaft.
B. Make sure the alignment dowel is perfectly smooth and round, without nicks or deformation.
C. Make sure that the shoulder of the dowel is 0.010 to 0.020 in. (0.25 to 0.51 mm) below the
surface of the crankshaft as shown in Figure 31.
D. Make sure the alignment dowel fits tightly in the crankshaft. It must not spin or be loose.
Figure 31
Section Through Counterbore End of Crankshaft
Showing Driven Height of Dowel
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March 2020
Results of Fluorescent Penetrant Inspection of Crankshaft
Black Light Inspection of Crankshaft Bore (inner diameter)
Corrective Action
Start of cracks or crack(s)
found - replace the crankshaft
Evidence of grinding - replace
the crankshaft
Rupture found - replace the
crankshaft
Discontinuity found - replace
the crankshaft
Inspector
Date of Inspection
Guidelines and
Findings and Action Taken
Acceptable
Replace
Acceptable
Replace
Acceptable
Replace
Acceptable
Replace
Figure 32
Details of Crankshaft Dowel
72-20
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