X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from omr-d03.mx.aol.com ([205.188.109.200] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6705465 for flyrotary@lancaironline.net; Mon, 27 Jan 2014 22:20:58 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.109.200; envelope-from=shipchief@aol.com Received: from mtaomg-mcb02.mx.aol.com (mtaomg-mcb02.mx.aol.com [172.26.50.176]) by omr-d03.mx.aol.com (Outbound Mail Relay) with ESMTP id C40C5701CDDAC for ; Mon, 27 Jan 2014 22:20:25 -0500 (EST) Received: from core-ddd002b.r1000.mail.aol.com (core-ddd002.r1000.mail.aol.com [172.29.52.197]) by mtaomg-mcb02.mx.aol.com (OMAG/Core Interface) with ESMTP id 91D4838000085 for ; Mon, 27 Jan 2014 22:20:25 -0500 (EST) References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: Exhaust Leak at Turbo Outlet Flange In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: shipchief@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8D0E9EF0538DEBB_75C_7009F_webmail-m267.sysops.aol.com" X-Mailer: AOL Webmail 38306-STANDARD Received: from 174.61.189.169 by webmail-m267.sysops.aol.com (64.12.145.225) with HTTP (WebMailUI); Mon, 27 Jan 2014 22:20:25 -0500 Message-Id: <8D0E9EF052F5937-75C-1E23F@webmail-m267.sysops.aol.com> X-Originating-IP: [174.61.189.169] Date: Mon, 27 Jan 2014 22:20:25 -0500 (EST) x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20121107; t=1390879225; bh=fMZJ7TgGE9eeh+CgPMIHbimCITXgtMJsI9uuPamNicE=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=sKfJjhegdgcPDaO0zYK/VWmWfS29YSnjDJUjDVRTcVYg74slnAOy/iZJ9Tki6n0Rr xrbzuLsScxKEVeO+4LVULDBULyfOqmId60lcnl/H1ZlFWYCiLzJ9MdpAipb+/jfv7V UMxygDDXAp6Nz6UyU9dw9zKXPov1XXBcoAMI5cQQ= x-aol-sid: 3039ac1a32b052e721f96139 This is a multi-part message in MIME format. ----------MB_8D0E9EF0538DEBB_75C_7009F_webmail-m267.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Dave; you pretty well summarized the problem. Ross the Subaru guy over on the VANs air force forum had valuable input as= well. After I cleaned up and inspected the mess, installed grade 8 bolts and gra= de C high temp lock nuts on the turbo mount flange. I used the stainless em= bossed shim type gasket. I assembled the turbine exhaust - to - exhaust pipe flange W/O gasket, usi= ng 1" grade 5 bolts that I had on hand. I used grade 8 washers, stacked bas= ed on the hole depth, they are not all the same depth. I removed the Kevlar exhaust pipe wrap, cut off an undamaged section, and = stuffed it into the burned thru hole in the turbo blanket. I made exhaust pipe heat shields out of cut offs from galvanized building = studs, left over from building my hangar. N89SE ran like a top, and made the 32 minute flight back to the Home Drome= with no trouble.=20 Today I shopped at the local specialty fastener store and picked up more G= rade 8 hardware and some 1/16" cobalt drill bits, no one seems to carry dri= lled head grade 8 bolts around here. I brought the top cowl home to repair the heat damaged spot over the turbo= . The repair might be an aluminum inspection door. Oh, one last thing; today I post flight inspected the repair, and all eigh= t fasteners took 1/12th of a turn to re-tighten. I figure that's just therm= al setting. Even if safety wired, they would need to be un-wired and re-tor= qued at least once?=20 (I posted similar on the VANs forum, so you might see this over there too) -----Original Message----- From: Lehanover To: Rotary motors in aircraft Sent: Mon, Jan 27, 2014 10:59 am Subject: [FlyRotary] Re: Exhaust Leak at Turbo Outlet Flange If you use locking nuts like Jet nuts that grip the stud, you just back out= the stud on removal. Use the stock nuts or stainless nuts and safety wire = them in the tightening direction. They never come loose and can be removed = without drama. On my NA engines I use no exhaust gasket. Just a bead of GE = 100% silicone tub and tile calk. Keep it well away from the ports. Never ha= d a leak, but I had no back pressure from a turbo hot section either. Might= be worth a try. =20 =20 Lynn E. Hanover =20 =20 =20 In a message dated 1/27/2014 9:09:09 A.M. Eastern Standard Time, cardmarc@c= harter.net writes: =20 =20 I believe Mazda uses some Inconel hardware on the 93+ 13Brew engines=E2= =80=A6=E2=80=A6=E2=80=A6=E2=80=A6found this out the hard and expensive wa= y. =20 Marc =20 =20 =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On B= ehalf Of David Leonard Sent: Saturday, January 25, 2014 8:14 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Exhaust Leak at Turbo Outlet Flange =20 =20 =20 =20 Bummer! Glad you are safe. =20 =20 =20 =20 =20 I use the stock steel nuts. Locknuts might be an improvement but not if = there is any non-steel component. I did loose one of those nuts once wit= hout to-do. Not sure how long it was gone. The other 2 held everything = together. =20 =20 =20 =20 =20 Be very careful with what gaskets you choose. I found some nice-looking = aftermarket turbo manifold gaskets for about $20 while the stock versions= are about $90 each, so I installed one. It lasted about 30 hours until = it disintegrated. The resulting exhaust leak burned through a coolant li= ne and I dead sticked onto a local airport (departing from a formation ro= utine at an airshow!.. complete with a cloud of steam). =20 =20 =20 =20 =20 Sigh, the stock ones are nothing but stainless steel layer, not some sort= of fiber stuff in the after market ones.=20 =20 =20 =20 =20 =20 On another occasion I was using some very nice and expensive exhaust clam= ps that were steel but I didnt notice that part of the block holding the = nuts was aluminum. About 50 hrs in something caused the alumimum to get = too hot, which created an exhaust leak, which accelerated the process. I= t burned a hole in the cowl and splatered molten aluminum everywhere - so= me of it is still around. =20 =20 =20 =20 =20 Another time I was using some fancy exhaust wrap. It slowly disintigrate= d over the course of 100+ hours and was generally an annoyance. =20 =20 =20 =20 =20 I tried a flowmaster hushpower muffler but melted most of the stuffing ou= t of it on the first flight. Luckily it melted pretty cleanly and didnt c= log the exhaust. =20 =20 =20 =20 =20 Moral of the story.. as if it didn't take me long enough to beat this th= rough my skull.. NOTHING that is not made of steel or better goes into a= ny part of the exhaust system. Particularly gaskets and nuts. =20 =20 =20 =20 =20 Guess I should have passed that one along sooner. Glad you got back safe= ly. Good job. =20 =20 =20 =20 =20 Dave Leonard =20 =20 On Sat, Jan 25, 2014 at 5:14 PM, wrote: =20 =20 =20 =20 =20 =20 =20 I had the nuts come loose on my turbo manifold on the block, I'm using = with out the turbo, so I drilled the nuts and secured them with wire. = JohnD =20 =20 =20 =20 =20 =20 Thanks for keeping us all informed , helps us all to make sure we look = for often simple overlooked areas. =20 =20 =20 =20 =20 Cheers =20 =20 Christian=20 =20 =20 Renises 13 b rv7 Sent from my iPad =20 =20 On 26/01/2014, at 3:17 AM, shipchief@aol.com wrote: =20 =20 =20 =20 During the 8th flight of my RV8 with 13B Turbo, I experienced an exha= ust leak at the turbo exhaust flange. I mistakenly used brass exhaust= nuts which are twice as tall as regular nuts. They work great on mo= st engines. I should have know better, as the temperature at the turb= o outlet, under the insulation is much higher. =20 =20 The brass nuts softened and deformed into a flange face at the washer= ! Once the tension was gone, the heat & vibration did the rest. =20 =20 The exhaust gasket blew where the gap was widest, at the top. =20 =20 The escaping heat burned thru the insulating jacket and the stick on = reflective aluminum. Then the fiberglass cowl charred, I smelled = that! =20 =20 I was close to my destination, and high, so I was able to pull off th= e power, put down the nosed and get on the ground without incid= ent. =20 =20 I'm disassembling it now, looks like I need 4 high temperature lock n= uts and a TO-4 exhaust flange gasket. I should review and improve the= insulation over the turbine housing. Also I need to repair the charr= ed area of the cowl, which might be in the form of an aluminum access= hatch. =20 =20 ----------MB_8D0E9EF0538DEBB_75C_7009F_webmail-m267.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8"
Dave;
you pretty well summarized the problem.
 Ross the Subaru guy over on the VANs air force forum had va= luable input as well.
After I cleaned up and inspected the mess, installed grade 8 bolts and gra= de C high temp lock nuts on the turbo mount flange. I used the stainless em= bossed shim type gasket.
I assembled the turbine exhaust - to - exhaust pipe flange W/O gasket, usi= ng 1" grade 5 bolts that I had on hand. I used grade 8 washers, stacked bas= ed on the hole depth, they are not all the same depth.
I removed the Kevlar exhaust pipe wrap, cut off an undamaged section, and = stuffed it into the burned thru hole in the turbo blanket.
I made exhaust pipe heat shields out of cut offs from galvanized building = studs, left over from building my hangar.
N89SE ran like a top, and made the 32 minute flight back to the Home Drome= with no trouble.
Today I shopped at the local specialty fastener store and picked up more G= rade 8 hardware and some 1/16" cobalt drill bits, no one seems to carry dri= lled head grade 8 bolts around here.
I brought the top cowl home to repair the heat damaged spot over the turbo= . The repair might be an aluminum inspection door.
Oh, one last thing; today I post flight inspected the repair, and all eigh= t fasteners took 1/12th of a turn to re-tighten. I figure that's just therm= al setting. Even if safety wired, they would need to be un-wired and re-tor= qued at least once?
(I posted similar on the VANs forum, so you might see this over there = too)
-----Original Message-----
From: Lehanover <Lehanover@aol.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, Jan 27, 2014 10:59 am
Subject: [FlyRotary] Re: Exhaust Leak at Turbo Outlet Flange

If you use locking nuts like Jet nuts that grip the stud, you just bac= k out=20 the stud on removal. Use the stock nuts or stainless nuts and safety wire t= hem=20 in the tightening direction. They never come loose and can be removed witho= ut=20 drama. On my NA engines I use no exhaust gasket. Just a bead of GE 100% sil= icone=20 tub and tile calk. Keep it well away from the ports. Never had a leak, but = I had=20 no back pressure from a turbo hot section either. Might be worth a try.=20  
 
Lynn E. Hanover
 
 
 
In a message dated 1/27/2014 9:09:09 A.M. Eastern Standard Time,=20 cardmarc@charter.net writes:
=20
=20
I believe Mazda=20 uses some Inconel hardware on the 93+ 13Brew engines=E2=80=A6=E2=80=A6=E2= =80=A6=E2=80=A6found this out the=20 hard and expensive way.
=20
Marc
=20
 
=20
= From: Rotary moto= rs in=20 aircraft [mailto:flyrotar= y@lancaironline.net] On Behalf Of David=20 Leonard
Sent: Saturday, January 25, 2014 8:14 PM
To:=20 Rotary motors in aircraft
Subject: [FlyRotary] Re: Exhaust Leak at=20 Turbo Outlet Flange
=20
 
=20
=20
Bummer!  Glad you are safe.
=20
=20
 
=20
=20
I use the stock steel nuts.  Locknuts might b= e an=20 improvement but not if there is any non-steel component.  I did loos= e one=20 of those nuts once without to-do.  Not sure how long it was gone.&nb= sp;=20 The other 2 held everything together.
=20
=20
 
=20
=20
Be very careful with what gaskets you choose. = ; I found=20 some nice-looking aftermarket turbo manifold gaskets for about $20 while = the=20 stock versions are about $90 each, so I installed one.  It lasted ab= out=20 30 hours until it disintegrated.  The resulting exhaust leak burned= =20 through a coolant line and I dead sticked onto a local airport (departing= =20 from a formation routine at an airshow!..  complete with a clou= d of=20 steam).
=20
=20
 
=20
=20
Sigh, the stock ones are nothing but stainles= s steel=20 layer, not some sort of fiber stuff in the after market=20 ones. 
=20
=20
 
=20
=20
On another occasion I was using some very nice and= =20 expensive exhaust clamps that were steel but I didnt notice that part of = the=20 block holding the nuts was aluminum.  About 50 hrs in something caus= ed=20 the alumimum to get too hot, which created an exhaust leak, which acceler= ated=20 the process.  It burned a hole in the cowl and splatered molten alum= inum=20 everywhere - some of it is still around.
=20
=20
 
=20
=20
Another time I was using some fancy exhaust= =20 wrap.  It slowly disintigrated over the course of 100+ hours and was= =20 generally an annoyance.
=20
=20
 
=20
=20
I tried a flowmaster hushpower muffler but melted = most=20 of the stuffing out of it on the first flight. Luckily it melted pre= tty=20 cleanly and didnt clog the exhaust.
=20
=20
 
=20
=20
Moral of the story..  as if it didn't take me= long=20 enough to beat this through my skull..  NOTHING that is not mad= e of=20 steel or better goes into any part of the exhaust system.  Particula= rly=20 gaskets and nuts.
=20
=20
 
=20
=20
Guess I should have passed that one along sooner.&= nbsp;=20 Glad you got back safely.  Good job.
=20
=20
 
=20
=20
Dave=20 Leonard
=20
=20
On Sat, Jan 25, 2014 at 5:14 PM, <down= ing.j@sbcglobal.net> wrote:
=20
=20
=20
 
=20
=20
I h= ad the nuts=20 come loose on my turbo manifold on the block, I'm using with = out=20 the turbo, so I drilled the nuts and secured them with wire. =20 JohnD
=20
=20
=20
 
=20
=20
Thanks for keeping us all informed , helps us all = to make=20 sure we look for often simple overlooked areas.
=20
=20
 
=20
=20
Cheers
=20
=20
Christian 
=20
=20
Renises 13 b rv7

Sent from my=20 iPad
=20
=20

On 26/01/2014, at 3:17=20 AM, shipchief@aol.com wrote:
=20
=20
=20
During the 8th=20 flight of my RV8 with 13B Turbo, I experienced an exhaust leak at the= =20 turbo exhaust flange. I mistakenly used brass exhaust nuts  whic= h are=20 twice as tall as regular nuts. They work great on most engines. I sho= uld=20 have know better, as the temperature at the turbo outlet, under the= =20 insulation is much higher.
=20
=20
The brass nuts=20 softened and deformed into a flange face at the washer! Once the tens= ion=20 was gone, the heat & vibration did the=20 rest.
=20
=20
The exhaust gasket= =20 blew where the gap was widest, at the top.
=20
=20
The escaping heat=20 burned thru the insulating jacket and the stick on reflective=20 aluminum. Then the fiberglass cowl charred, I smelled= =20 that!
=20
=20
I was close to my=20 destination, and high, so I was able to pull off the power, put down = the=20 nosed and get on the ground without=20 incident.
=20
=20
I'm disassembling=20 it now, looks like I need 4 high temperature lock nuts and a TO-= 4=20 exhaust flange gasket. I should review and improve the insulation ove= r the=20 turbine housing. Also I need to repair the charred area of the cowl, = which=20 might be in the form of an aluminum access=20 hatch.
=20
 
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