IO-390-D Series Engine Maintenance Manual
12-10
© 2020 Avco Corporation. All Rights Reserved
Page 76
March 2020
IO-390-D Series Engine Maintenance Manual
NOTICE:
Table 2 only applies to engines that use genuine Lycoming Parts.
Table 2
Guidelines for Identification of Metal Particulates and Chips & Corrective Action
Metals/
Alloys
Tests & Characteristics
Possible Source of Origin
on Lycoming Engine
Next Step
Steel or cast
iron
Picked up by magnet or,
will move when a magnet
is placed on the opposite
surface of the filter
element or strainer cloth –
which will prevent chips
from sticking to the
magnet
Camshaft lobes
Gears
Tappets
Push rods
Rockers
Shafts
Impellers
Piston rings
Cylinder barrels
Refer to Table 3 for
the quantity and size
of the particles
Bronze
When placed in nitric
acid, turns bright green
Connecting rod bushings
Rocker bushings
Crankshaft bearings
Intake valve guide
Piston pin plug
Idler gear bushing
Refer to Table 3 for
the quantity and size
of the particles
Nickel
Not picked up by magnet
Exhaust flange
V-band coupling
Gasket
Refer to Table 3 for
the quantity and size
of the particles
Stainless steel
Valves
Exhaust components
Valve seats
Oil bypass valve spring
Safety wire
Refer to Table 3 for
the quantity and size
of the particles
Chrome
Piston rings
Exhaust valve stems
Refer to Table 3 for
the quantity and size
of the particles
Copper
When placed in nitric
acid, turns bright green
Platings
Refer to Table 3 for
the quantity and size
of the particles
Brass
When placed in nitric
acid, turns bright green
Oil suction screen
Pressure relief valve
spacer
Refer to Table 3 for
the quantity and size
of the particles
