Engine Assembly; Corrosion Prevention; Painting The Engine And Engine Components - Lycoming IO-390-D Series Maintenance Manual

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

1. Corrosion Prevention

CAUTION USE ONLY THE RECOMMENDED LUBRICANT OR EQUIVALENT
DURING ENGINE ASSEMBLY.
A. Pre-Lubrication of Parts Before Assembly
Before assembly of each subassembly, clean all of the parts to remove the preservative oil,
grease, and unwanted dirt per instructions in Chapter 05-30.
As preventive action, during engine assembly, apply the recommended lubricant for specified
components identified in the latest revision of Service Instruction No. SI-1059.
If parts are not correctly lubricated, or if a lubricant other than what is recommended is
applied to a part, engine parts could become scored before the engine oil has lubricated the
parts during the first cycle of engine operation. This scoring can cause premature part failure,
or, in some cases, engine failure.

2. Painting the Engine and Engine Components

Lycoming Engines recommends that the basic engine be painted as an assembly (without
accessories, intake tubes, fluid lines, wiring harness). However, if it is necessary to paint an
individual component:
• Do not get paint on any mating surfaces or under the cylinder hold down nuts.
• There must be metal-to-metal contact to ensure correct torque.
• Mask mating surfaces and the area where the nut will contact the component surface.
Table 1 includes paint stripping and painting guidelines for components.
All paint is to be sprayed; however, if it is necessary to use a brush, use care to prevent an
accumulation of pockets of paint. Refer to the paint manufacturer's instructions for drying and
curing times.
Parts requiring use of paint for protection or appearance are to be painted in accordance with the
recommendations using the following approved materials:
• Thinner - Toluene or equivalent (AMS3180 or equivalent Federal Spec. TT-T-548).
• Primer - Zinc chromate (AMS3110 or equivalent MIL-P-8585).
• Enamel - Phthalate resin type (AMS3125C or equivalent MIL- E-7729).
NOTICE: All machined bosses are to be masked before painting. Do not paint areas under
hold- down nuts where torque is required.
Paint Stripping and Painting Guidelines for Components
Aluminum and NOTICE: It is not necessary to apply the primer coat if paint has not been
Steel Parts
(1) Clean and degrease the parts with mineral spirits or equivalent.
(2) Apply one coat of zinc chromate primer, thinned with two parts toluene.
(3) Air dry.
(4) Apply one coat of enamel and bake at 250° to 300° F (121 to 149° C), for
© 2020 Avco Corporation. All Rights Reserved
March 2020

72-10 - ENGINE ASSEMBLY

removed from the part.
1/2-hour.
Table 1
72-10
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