Tighten loose mountings to obtain torque
values specified In maintenance manual.
Repair or replace vibration isolators that
show any evidence of radial slippage.
Properly secure all engine mount retaining
bolts with safety wire.
Replace vibration isolators when metal or
rubber parts indicate sagging or deterioration.
7-12. Preservation of Reciprocating Engines.
Corrosion of aircraft metals and alloys is primarily a light
against moisture. There are two main types of surface
corrosion, direct chemical attack on metal, and
electrochemical action In which the metal being
corroded becomes a part of an electrolytic cell In the
presence of moisture. Both reactions are effectively
retarded In the absence of moisture. Corrosion will not
occur in a clean atmosphere when moisture is not
permitted to reach the metal surface. Preserve
reciprocating engines using the following paragraphs.
Engines removed from an aircraft that has been
involved in an accident In which engine failure or
malfunction Is known or suspected to have been a factor
should not be treated with corrosion protective. No
attempt should be made to operate, motor, or
disassemble an accident-involved engine. All accident
involved engine must be transported to an overhaul
depot or a designated investigation area within 10 days
after the accident. The accident-involved engine shall
be preserved using the following procedures.
Without disconnecting lines or fittings,
make every effort to prevent remaining fuel and oil In
engines from leaking out
Plug all ports and cap all fittings and lines.
Seal openings with applicable covers.
Install engine in bottom half of metal,
reusable shipping and storage container.
Ground engine to container to prevent a
possible explosion of dangerous vapors which may be
ignited by static electricity or a spark.
Secure all loose metal components to the
container with tape, PPP-T-60, to prevent a possible
spark during shipment.
Preservation of Operable Engines to be
removed for Overhaul. Engines to be removed from
aircraft for overhaul, that can be operated without
further damaging the engine or any of its parts, shall be
preserved using the following procedures
compound, be sure none of the
compound is injected into airstream
of the carburetor or master control.
Damage may otherwise result.
Drain oil system and refill with corrosion
preventive MIL-C-6529, Type II.
Type II corrosion preventive consists
of a ready mixed blend of 1 part
Type 1 and 3 parts new lubricating
oil, MIL-L-6082, Grade 1100.
Prior to starting engine for final run,
connect discharge nozzle.
Discharge nozzles shall conform to
designs set forth in figure 7-24 and
be modified in length and thread
configuration to suit engine type and
point of application.
Locate nozzle in a position so that
corrosion preventive mixture Is properly distributed to all
cylinders. Modify nozzle discharge are to provide
sufficient restriction to prevent exhausting corrosion
preventive supply prior to cessation of engine rotation.
For radial engines, precautions shall
be taken to ensure that the quantity
of mixture aspired and the location
employed provides an even amount
of coating for both upper and lower