Message-ID: <003a01bf49f4$5de686e0$b66b1b3f@oemcomputer>
Reply-To: "dfs" <dfs@gateway.net>
From: "dfs" <dfs@gateway.net>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: O-290 & O-235s
Date: Sat, 18 Dec 1999 23:40:16 -0800
Mime-Version: 1.0

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William T Bartlett's information sounds like it's coming from a guy who
knows his stuff.

What I'm not sure of though is whether that much in-depth data will help
someone to make the choice between an O-235 and O-290. I don't disagree with
him as I'm not an aircraft wrench - however my comment about the
desireability of starting with the -L2C version of the O-235 comes from the
fact that the -L2C and -N2C were the latest versions of this venerable old
boat anchor - and I just figured that'd be the best place to start as long
as you are purchasing the engine anyway.

My suggestion that the -L2C was the one to start with (compared to the -N2C)
stems from the fact that Lycoming had serious lead fouling problems with
the -L2C on 100LL (and this on an engine touted to be designed expressly FOR
100LL!) and tried to correct it by putting small relief "pockets" in the
combustion chamber adjacent to the valve heads (thereby creating the -N2C
version). Doing so lowered the compression ratio a bit because of the
slightly increased combustion chamber volume and, therefore, the rated HP -
so if you're going for the high compression pistons to up the HP, the
resulting compression ratio comes out somewhat higher in the -L2C. Which is
what your money is going for in the first place.

But hey! As I've said many times before here, you pays your money and you
takes your chances!

Dan Schaefer

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