Limits And Clearances; Inspections - Lycoming IO-390-D Series Maintenance Manual

IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
Paint Stripping and Painting Guidelines for Components
(5) Use a cloth dipped in paint thinner to remove paint from all surfaces where
Cylinder (Cont.)
(6) Air-dry the cylinder or bake the cylinder in an oven until completely dry.
(7) Refer to Chapter 74-20 and paint the cylinder fin area appropriately for

3. Limits and Clearances

Refer to the latest revision of Service Table of Limits - SSP-1776, for the following.
• Backlash and end clearance of gears
• Clearance between mating machined parts
• Clearance between moving parts that touch
• Torque limits for various nuts, screws, and fasteners.

4. Inspections

NOTICE: Inspections in this section refer to reusable items that do not require replacement in
accordance with the latest revision of Service Bulletin No. SB-240. Be sure to record
part replacement or any corrective action in the engine logbook.
A. Bearing Surface Inspection
(1) Examine all bearing surfaces for scoring, galling, and wear. If a part has one of the
defects, discard it and replace it with a new one.
(2) Make sure that the clearance of each bearing agrees with the specification in the latest
revision of the Service Table of Limits SSP-1776.
• If a bearing is not in the specified limits in the latest revision of the Service Table of
Limit - SSP-1776, discard it and replace it with a new one.
(3) Examine all journal surfaces for galling, scores, misalignment, and out-of-round
condition. Replace a scored, galled, misaligned, or out-of-round component.
(4) Examine the shafts and pins for straightness.
B. Gear Inspection
(1) Examine the involutes of the gear teeth for pitting and excessive wear.
• If pit marks are found, discard the gear and replace it with a new one.
(2) Examine the bearing surfaces of all gears for deep scratches.
(3) Remove minor abrasions with a fine abrasive cloth.
C. Screwed Fitting Inspection
(1) Examine the condition of the threads on screwed fittings (threaded fastenings or plugs).
(2) Remove small nicks and burrs with a small file, fine abrasive cloth, or stone.
• If the part cannot be repaired by polishing it, discard it and replace it with a new one.
• If the part has too much distortion, galling, or mutilation (caused by over-tightening
or use of an incorrect tool) replace it.
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March 2020
Table 1 (Cont.)
it could have accidentally accumulated.
Refer to the paint manufacturer's instructions for drying time and oven
temperature.
spark plug identification.
72-10
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