Camshaft Inspection - Lycoming IO-390-D Series Maintenance Manual

IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual

9. Camshaft Inspection

There are two parts to the camshaft inspection: a
visual inspection and a dimensional inspection.
Copy and complete the Camshaft Inspection
Checklist to do the camshaft inspection.
NOTICE If a new or reconditioned camshaft is to
be installed, install new tappet bodies.
Refer to the "Camshaft Replacement
Guidelines" section in the latest revision
of Service Instruction No. SI-1011 for
guidelines on replacing the camshaft
when new tappets are installed in the
engine.
If a hydraulic tappet body has been
rejected for spalling, carefully examine
the corresponding camshaft lobe for
evidence of distress, surface
irregularity, or feathering on the edges.
Camshaft Inspection Checklist for IO-390-D Series Engines
Item
Camshaft Visual Inspection
Visually examine all surfaces of the camshaft (Figure 33) – give particular attention to bearing
surfaces and camshaft lobes. If any of the following conditions are found during this visual
inspection, replace the camshaft: cracks, scoring, galling, corrosion, pitting, feathering (at edge of
camshaft lobes or bearing), surface irregularity, distress/fatigue, or other damage
Acceptable
(No crack, scoring, galling, corrosion, pitting, feathering (at edge of camshaft
lobes or bearing), surface irregularity, distress/fatigue, or other damage)
Camshaft
Replace
Comment- condition(s) found:
Camshaft Dimensional Inspection
Support the camshaft in V-blocks and measure the
run-out. For mounting locations and clearances,
refer to the latest revision of the Service Table of
Limits - SSP-1776. If the run-out is out of
tolerance, replace the camshaft.
Measure the OD of the camshaft at the bearing
locations and compare the results to the bearings
formed by the crankcase (per the "Crankcase
Dimensional Inspection" in this chapter.) If the OD
is not within limits, replace the camshaft.
© 2020 Avco Corporation. All Rights Reserved
March 2020
Comments
Run-out
measurement:
Figure 33
Camshaft with Integral Gears
Findings/
Corrective Action
Acceptable
Replace
Acceptable
Replace
Done
72-20
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