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Date: Wed, 23 Jan 2013 15:14:02 -0500
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From: "Mark  Ravinski" <mjrav@comcast.net>
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Subject: Re: [LML] Plenum only to Cylinder heads
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Paul,
I built a plenum as you describe back many years ago for my 360.
It works great.  I can't find the pictures of it now but I did post them on 
the LML previously.
You might find them with a search.  I made the inside surface by fitting 
some .062" G-10 flat sheet between the last two fins on each barrel.

Mark Ravinski
IO360   1554 hrs

--------------------------------------------------
From: "Paul Miller" <pjdmiller@gmail.com>
Sent: Wednesday, January 23, 2013 8:27 AM
To: <lml@lancaironline.net>
Subject: [LML] Plenum only to Cylinder heads

> Thinking about all the air leaks that typically show up in the IO550 
> Legacy cowl. A full size plenum has been accomplished by some folks.  What 
> about a plenum that went from the inlet and simply exited onto the three 
> cylinder heads on that side?  It would be smaller, maybe easier to build, 
> lighter.   You could use a silicone seal where it would fit on the barrel 
> to keep a tight fit and wires could be kept away I believe.
>
> How much better would the cooling be and would the lack of air to the rest 
> of the crankcase or cylinder bases cause problems?   Still need to route 
> some bleed to the accessories and oil cooler which we do already but I'm 
> talking about ducting the inlet straight to the head and avoiding most of 
> the leakage points and perhaps achieving better overall cooling.
>
> Second:  Why does the alternator duct exit below the engine?  The exit air 
> may be warm but certainly less than CHT so why not duct the alternator 
> exit back into the upper deck and regain the pressure loss that goes 
> straight through the alternator and bypasses the cylinder fins?
>
> Thoughts?
>
> Paul
> Legacy
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