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Message-ID: <20041126001135.6410.qmail@web51103.mail.yahoo.com>
Date: Thu, 25 Nov 2004 16:11:35 -0800 (PST)
From: Steve Brooks <prvt_pilot@yahoo.com>
Subject: Re: [FlyRotary] sealant question
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-546087@logan.com>
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Marcv,
Halomar is a blue compound that is more grease-like
than anything.  I don't know if halomar ever does
harden.  I think that it just gets sticky.

The gray subtance that you described, sounds like
Permatex Ultra-Gray.  It is often used on parts when
rebuiding rotaries.

My understanding is that Ultra-gray is not corrosive
to aluminum, and makes a pretty good gasket/sealant.

Steve Brooks

--- Marvin Kaye <marv@lancaironline.net> wrote:

> 
> First of all, I hope everyone had a happy
> Thanksgiving.
> 
> I managed to spend the better parts of the last 2
> days getting everything 
> disconnected from the top of the Eagle in order to
> pull the intake manifold... 
> we were attempting a full power runup when, at about
> 3450rpm, I saw 3 puffs of 
> black smoke from the left exhaust, and the aircraft
> owner (in the pilot seat) 
> saw something cloudlike fly over the top of the
> fuselage.  He shut it down and 
> we found, upon inspection, that there was coolant on
> top of the gearbox, 
> obviously from a leak at the front of the intake
> manifold.  I did a 
> compression check yesterday to verify that we hadn't
> blown a head gasket and 
> that test yielded excellent results (all cyls 175psi
> +3 psi max), so the heads 
> are ok.
> 
> I finally got the intake manifold off late this
> afternoon and found that they 
> use o-rings to seal both the intake and coolant
> ports between the heads and 
> the manifold.  The throttle body appears to be
> gasketed to the manifold only 
> with a thin film of red RTV between the ground
> surfaces.  The o-ring grooves 
> and the areas between them, however, were sealed
> with a light grey material, 
> with a texture very like silicone, but it only stuck
> to the primed (I assume 
> it's primed) inner surface of the manifold, not the
> ground surfaces that it 
> mates to on the heads.  Is it possible that this is
> Hylomar?
> 
> I'm not sure about why the leak developed yet, as
> the gasketing all appreared 
> to be ok... but I want to insure that when I put
> everything back together with 
> new cork gaskets between the front & rear top edges
> of the block-to-mainfold 
> junction and new o-rings on the heads that I use the
> proper sealant.  I was 
> afraid that getting the manifold off was going to be
> a complete PITA but it 
> actually popped off pretty easily, due to the
> sealant used and its lack of 
> adhesion with the raw metal surfaces of the heads. 
> I'd like to insure that 
> the next person (sure hope it's not me <g>) that has
> to remove the manifold 
> has no harder a time than I did so would like to use
> the same kind of sealant. 
>  TIA for the help.
> 
>     <Marv>
>  
> 
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:  
> http://lancaironline.net/lists/flyrotary/List.html
>