Message-Id: <9903229221.AA922117723@inet001.cardell.com>
Date: Mon, 22 Mar 99 09:48:45 -0500
From: <dechaze@cardell.com>
To: <lancair.list@olsusa.com>
Subject: Re: LC20 Intake system
Mime-Version: 1.0

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Well, I figured my "academic credentials" note would get a reaction from
somebody.  My last couple of postings have not gotten answers so I had to turn
it up a bit.  Here's a brief description of how I've set up the intake system on
my IO-360 in the two-seater.  If anybody else out there stressed over this like
I did, maybe you'll get some benefit.  I invite critiques also, in case I
engineered in a problem.

>From the bottom of the oil pan I come forward with a 90 degree elbow.  To this I
mount the injection unit.  Mixture is on the co-pilot side.  The mixture control
arm threatened to interfere with the cowl splash but fortunately the fellow who
sold me the elbow (and y-pipe below) also had a variety of replacement mixture
control arms.  To the front of the injection unit I mount an off-the-shelf Y
pipe with integral flapper.  It's a big unit, 3.5 inch tubing about 6 inches
long, but comes with an adaptor to mount to the injection unit and reduce
diameter as the air enters the injection unit.  The reason I went with this Y
setup is that I wanted Ram air control and was nervous about building my own
configuration due to the possibility of ingesting broken components.

>From here, I go forward (only 2.5 inches) to the front of the cowl for ram air
(not installed yet) and go sideways to get filtered air.  The filter is mounted
in front of the number 1 cylinder (co-pilot's side) since the number 2 cylinder
area is occupied by the oil cooler.  It's a small off-the-shelf "Brackett"
filter assembly about 5 inches by 5 inches.  It's a replacement part for Cessna
152s among others.  (if the filter's too small, what bad things happen besides
lower manifold pressure?) The trick is to connect the SCAT tube between the Y
and the filter assembly.  This is done by fashioning a plenum at both ends.  The
plenum at the filter is straight forward, similar to what most of you have done
with your oil coolers.  The plenum at the Y must squeeze between the lower cowl
and the alternator and is tight.  The cowl (deep splash required) requires a
little relieving in this area and the SCAT tube is squeezed to an oval. 

The ram air cable routes on the pilot side and passes between the exhaust and
the cowl.  The handle (along with heater control) is tucked under the panel,
against the fuselage side, just forward of the knee.  The throw is short and
nearly frictionless.  The firewall forward is nearly complete and everything
seems to fit.  A complication was the heater SCAT routing.  I have the small
tube routing under the intake/exhaust pipes and the large tube routing between
the pipes and the heads.  Reversing this was possible but caused an interference
with the lower cowl.  The small SCAT tube has a bit of fiberfrax material
siliconed to it where it touches the number 1 exhaust pipe (will that work?).   


So there you have it.  Of course everything sounds good before the first engine
start I imagine.  If anyone is interested in part numbers and sources for the
off the shelf parts, I'd be happy to dig them up. 

Oh, and a special thanks to the list participant who suggested I solve my
dip-stick to mount interference problem by cutting it and sleeving it with
rubber hose.  Solved the problem.

Ed de Chazal
Rochester Michigan