Posted for "Cy Galley" <cgalley@qcbc.org>:
Your point about fitting materials is a very valid one.  The fact that the
drains are aluminum is not. No pressure. The lines to your filter or cooler
are using pressure but it a continual pressure not a varying pressure line a
prop line. I would imagine that under the right conditions, a harmonic or an
"oil hammer" might be induced in the prop line which might be the reason for
Lycoming to go with steel fittings.

That's my SWAG!

Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh

Editor, EAA Safety Programs
cgalley@qcbc.org or experimenter@eaa.org

Always looking for articles for  the Experimenter

You might want to look at the oil drains on any Lycoming engine, they are
Aluminum AN  fittings.
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