Date: Tue, 05 Dec 2000 08:00:41 -0800
From: Greg Nelson <gregsays@swbell.net>
Subject: Read your cowlings
To: "lancair.list@olsusa.com" <lancair.list@olsusa.com>
Message-id: <3A2D1129.4E3FD71D@swbell.net>
Reply-To: lancair.list@olsusa.com
Mime-Version: 1.0

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On performing my annual inspection yesterday, I noticed some "blowby"
traces on the lower cowling immediately below the No. 3 cylinder.  I
visually examined each of my exhaust pipes and could see no cause for
blowby but the indications were unmistakable.  I also noticed the No. 3
cylinder exhaust pipe had fractional movement whereas the other exhaust
pipes had virtually no movement.  I removed the retaining nuts of that
exhaust pipe and found a hairline crack surrounding the flange which
anchors the exhaust pipe to the cylinder head.  The reason that the
exhaust pipe had not moved and vibrated out of position is that it was
braced in two other locations along its length.  Even though it was
cleanly broken, it couldn't move out of position.  Of course, such
exhaust pipe bracing is just good construction technique called for by
Lancair and all others.  Perhaps the bracing saved my life and my
beautiful Lancair.

I habitually examine the insides of my lower and upper cowling each time
I remove them.  The cowlings report a lot of information about an engine
including serious chafing of the engine to the cowling, incorrect or
inadequate sealing of the baffling seals to the upper and lower cowlings
(inadequate or faulty cooling of your engine).  The oil leaks of your
engine are easily traceable and alternator belt wear will be apparent in
and around the starter ring.  In this particular inspection yesterday,
the blowby of the exhaust was clearly (but faintly) visible and it had
spread evenly around cylinder No. 3 thus, leading me to my broken
exhaust pipe.

I recommend that your regularly "read" your interior cowlings for clues
on the operating health of your engine.  After each removal (and after
reading), clean them thoroughly so that on next removal you can see all
of the most recent new clues and deposits.   Greg Nelson

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Please send your photos and drawings to marvkaye@olsusa.com.
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