REFLECTOR: IO-540 Engine Plenum & lower baffles

[Keith Hallsten]

This is timely as I am working on the plenum for my IO-540 (260 hp) right
now.  It appears that the factory plenum leaves a HUGE hole on the front
side of cylinder #6.  I assume that this needs to be covered with a separate
piece, laid up on tape on the cylinder and attached to the rest of the
plenum with screws.  Is this right, or am I missing something?

Also, I see Ron used stainless steel for his lower baffles.  I've seen
others use aluminum.  A friend building a Cozy told me his "factory"
instructions call for laying up 2-bid in red RTV, then attaching that (after
cure) to the plenum with screws.  Dave Dent advised me to lay up the RTV/bid
directly onto the cylinders wet, and let it cure/bond right on to the edges
of the cooling fins.  Anyone else want to make a suggestion on lower baffle
installation?

Keith Hallsten
  

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Ron Brown
Sent: Monday, August 29, 2005 7:05 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Engine Plenum

Correct.  The 2 bid gap filler lays on the case rather than butting up 
against it.

The cylinder wraps (on the bottom of the cylinders) holds the plenum down.

See http://home.sprintmail.com/~romott/page55.html



----- Original Message ----- 
From: "Scott Derrick" <scott at tnstaafl.net>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Monday, August 29, 2005 6:48 PM
Subject: Re: REFLECTOR: Engine Plenum


> Ron,
>
> So you put a kind of "foot" on the plenum so the sharp edge wasn't riding 
> on the case?
>
> How did you hold the plenum down?
>
> thanks,
>
> Scott
>
> Ron Brown wrote:
>
>> Scott,
>>
>> I did use the factory plenums but I taped up the engine with duct tape 
>> where the plenums meet the engine case.  Then I laid up two bid from the 
>> plenum onto the tape to make a tight fitting seal - but did not use any 
>> silicone. I think the silicone gets used when folks are having cooling 
>> problems and have to get an airtight seal.
>>
>> My IO360 runs very cool with the set up I have.
>>
>> Ronnie
>>
>>
>>
>> ----- Original Message ----- From: "Scott Derrick" <scott at tnstaafl.net>
>> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>> Sent: Monday, August 29, 2005 5:09 PM
>> Subject: Re: REFLECTOR: Engine Plenum
>>
>>
>>> Its hard to believe that nobody here has built their plenum with an 
>>> improvement over the method shown in the manual?
>>>
>>>
>>> Scott Derrick wrote:
>>>
>>>> I was fitting the plenum on my TSIO520 today,  cutting and filing to 
>>>> get it as low as possible to allow room for a partially modified upper 
>>>> standard cowling.   After I shortened the upper deck manifold and 
>>>> rerouted some of the injection lines I got it as low as practicable.
>>>>
>>>> Now I would like to make the edges that contact the engine more 
>>>> "rubbing" friendly with some kind of silicone edging, it would be nice 
>>>> to have something that slipped over the edge like door seal stuff. 
>>>> What are people using?  I know I can cut Silicone baffle strips and 
>>>> glue and rivet but I thought there might be something a bit more cool 
>>>> looking.
>>>>
>>>> I looked on the Velocity site and the gallery and the only thing I saw 
>>>> was siliconing(as in gluing) the edges to the engine(YUCK).
>>>>
>>>> Also how are people attaching the firewall, runner to plenum assembly. 
>>>> The manual has a direct connection which has no slip joint to 
>>>> accommodate the engine moving around.
>>>> Also regarding the runners to the firewall, the manual has us using the

>>>> cowl screws to hold the runner to the firewall. I'm still toying with 
>>>> the idea of a groove for the cowl to slip into and doing away with all 
>>>> those screws.   Any other suggestions?
>>>>
>>>> I searched my email archives and came up with nada on "plenum" in the 
>>>> subject line.
>>>>
>>>> Pictures are of course are greatly appreciated.
>>>>
>>>> Scott
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>>>>
>>>>
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>>
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