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To: flyrotary@lancaironline.net
Subject: Exhaust Leak at Turbo Outlet Flange
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From: shipchief@aol.com
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Message-Id: <8D0E80866C256A7-92C-F8D7@webmail-d222.sysops.aol.com>
Date: Sat, 25 Jan 2014 12:17:04 -0500 (EST)

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During the 8th flight of my RV8 with 13B Turbo, I experienced an exhaust le=
ak at the turbo exhaust flange. I mistakenly used brass exhaust nuts  which=
 are twice as tall as regular nuts. They work great on most engines. I shou=
ld have know better, as the temperature at the turbo outlet, under the insu=
lation is much higher.
The brass nuts softened and deformed into a flange face at the washer! Once=
 the tension was gone, the heat & vibration did the rest.
The exhaust gasket blew where the gap was widest, at the top.
The escaping heat burned thru the insulating jacket and the stick on reflec=
tive aluminum. Then the fiberglass cowl charred, I smelled that!
I was close to my destination, and high, so I was able to pull off the powe=
r, put down the nosed and get on the ground without incident.
I'm disassembling it now, looks like I need 4 high temperature lock nuts an=
d a TO-4 exhaust flange gasket. I should review and improve the insulation =
over the turbine housing. Also I need to repair the charred area of the cow=
l, which might be in the form of an aluminum access hatch.

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<font color=3D'black' size=3D'2' face=3D'arial'>
<div><font style=3D"background-color: transparent;">During the 8th flight o=
f my RV8 with 13B Turbo, I experienced an exhaust leak at the turbo exhaust=
 flange. I mistakenly used brass exhaust nuts&nbsp; which are twice as tall=
 as regular nuts. They work great on most engines. I should have know bette=
r, as the temperature at the turbo outlet, under the insulation is much hig=
her.</font></div>

<div>The brass nuts softened and deformed into a flange face at the washer!=
 Once the tension was gone, the heat &amp; vibration did the rest.</div>

<div>The exhaust gasket blew where the gap was widest, at the top.</div>

<div>The escaping heat burned thru the insulating jacket&nbsp;and the stick=
 on reflective aluminum.&nbsp;Then&nbsp;the fiberglass cowl&nbsp;charred, I=
 smelled that!</div>

<div>I was close to my destination, and high, so I was able to pull off the=
 power, put down the nosed and get on the&nbsp;ground without incident.</di=
v>

<div>I'm disassembling it&nbsp;now, looks like I need 4 high temperature lo=
ck nuts and a TO-4 exhaust flange gasket. I should review and improve the i=
nsulation over the turbine housing. Also I need to repair the charred area =
of the cowl, which might be in the form of an aluminum access hatch.</div>
</font>
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