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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
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