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Date: Thu, 09 Aug 2007 08:25:33 -0400
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Subject: Fine points of fitting a 320 engine in a 235
From: "bob mackey" <n103md@yahoo.com>
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> For those of you who have installed Lycoming 320 engines
> in a Lancair 235, can you give me some hints, the pro's
> and con's, and the main challenges you ran in to.
>
> Thanks
> Don Asher

Don:

I would be happy to show you my L235/O-320 installation.
Where do you live?

It was originally built by Mike DeHate in 1988,
and I have since refined a few things.  This
aircraft is fitted with an O-320-A2B, narrow deck,
conical mount. It is not roomy behind the engine,
but the space is adequate, once you figure out how
to get the allen wrench into the fuel pump bolts.

The exhaust crosses over in the front and apparently
performs well. It is both quiet and powerful.
One of the exhaust manifold nuts is very difficult
to tighten even with the specially-ground socket.
I'd make that a bit different.

I have an updraft carburetor and forward-facing airbox.
There is a forward inlet on the lower cowl.

Aymar-Demuth developed a 64x78 wood prop for this aircraft
and it seems to work well. I cruise as fast as other
320's, and have no complaints about the climb. The glide is
at least 10:1, but a C/S prop would help with steep descents
to short runways. It would also add several pound to the nose
which might increase the weight I can carry behind the seats
(max 80 lbs now).

Battery is behind the seat. Hydraulic pack is behind the aft
bulkhead.

The upper cowl on the 235 has a fairly flat section over the
engine. That area will oil can in flight. I ending up reinforcing
with 0.100" nomex core and 1 play of 3K carbon. Best to do that
before cutting all the baffling to fit.

Come by and take a look, or I'll have to post lots of photos.

-bob