I find my = Inconel metric exhaust hardware in the piles of removed OEM turbo stuff = the =E2=80=98racers=E2=80=99 take off to go single turbo on the later = (93+) models. Works for me.

Marc

From:= = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of marv@lancair.net
Sent: Friday, January 31, 2014 = 7:14 AM
To: Rotary motors in aircraft
Subject: = [FlyRotary] Re: Exhaust Leak at Turbo Outlet = Flange

You might = want to check out McMaster Carr... they have 18-8 bolts (actually cap = screws) with drilled heads... go to their site mcmaster.com and = put 90121A581 into the search box... it's probably = not the right size bolt but it will take you to that catalog page. = Unfortunately they don't appear to have them in metric sizes, but = once you get past 1/4" you can frequently use SAE sizes in lieu of = the metric(as long as you're providing both screw & nut.... thread = pitches don't match.) BTW, take a look at 321 stainless for the = stuff you're thinking about doing in Inconel... IHTH. = <Marv>

shipchief@aol.com = wrote:

>
> Lynn,
> I think you are right about = bolt material, I looked up grade 8 steel, it's
>only rated to 450 = degrees F. 18-8 (304) stainless, although much weaker, has =
>incredible temperature range .  It's rated for = pressure vessel service to
>about 1300F and general use to = 1690F.
> So I just  broke off a 1/16" drill in the = head of an 18-8 stainless bolt,
>trying to make it accept safety = wire. I'll keep working on that.
> I'm considering Inconel 600 = hardware for the turbo inlet flange, it's rated
>to 2000F, but = I'll try the stainless there for now, and watch it a lot.
> I plan = to trim large diameter washers to fit tight against the turbo and =
>header bodies, then after tightening the bolts, = bend  the washer edge up to
>act as a lock tab.
> =
>
>
> -----Original Message-----
>From: = shipchief shipchief@aol.com
> To: = Rotary motors in aircraft <flyrotary@lancaironline.net>
> Sent: Mon, Jan 27, 2014 7:22 pm
> Subject: = [FlyRotary] Re: Exhaust Leak at Turbo Outlet Flange
>
> =
> 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 grade
>C high temp lock nuts on the = turbo mount flange. I used the stainless
>embossed shim type = gasket.
> I assembled the turbine exhaust - to - exhaust pipe = flange W/O gasket, using
>1" grade 5 bolts that I had on = hand. I used grade 8 washers, stacked based 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
>Grade 8 hardware and some 1/16" cobalt drill = bits, no one seems to carry
>drilled 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 eight
>fasteners took 1/12th of a turn to = re-tighten. I figure that's just thermal
>setting. Even if safety = wired, they would need to be un-wired and re-torqued
>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 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 had
>a leak, but I had no back pressure from a turbo = hot section either. Might be
>worth a try.
> =
> Lynn E. Hanover
>
>
>
>
> In = a message dated 1/27/2014 9:09:09 A.M. Eastern Standard Time,
>cardmarc@charter.net = writes:
>
>
> 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 way.
>
> = Marc
>
>
>
>From: = Rotary motors in   aircraft [mailto:flyrotary@lancaironlin= e.net] On
>Behalf 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
>
> =
>
>
> Bummer!  Glad = you are safe.
>
>
> =
>
>
> 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
>without to-do.  Not = sure how long it was gone.    The other 2 held = everything =
>together.
>
>
> =
>
>
> 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 line
>and I dead sticked = onto a local airport (departing   from a formation routine =
>at an airshow!..  complete with a cloud of   = steam).
>
>
> =
>
>
> Sigh, the stock ones = are nothing but stainless steel   layer, not some sort =
>of fiber stuff in the after market   ones. =
>
>
> =
>
>
> On another occasion I = was using some very nice and   expensive exhaust =
>clamps 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.
> It burned a hole in the = cowl and splatered molten aluminum   everywhere -
>some = of it is still around.
>
>
> =
>
>
> Another time I was = using some fancy exhaust   wrap.  It slowly = disintigrated
>over the course of 100+ hours and was   = generally an annoyance.
>
>
> =
>
>
> I tried a flowmaster = hushpower muffler but melted most   of the stuffing out =
>of it on the first flight. Luckily it melted pretty   = cleanly and didnt clog
>the = exhaust.
>
>
> =
>
>
> Moral of the = story..  as if it didn't take me long   enough to = beat this
>through my skull..  NOTHING that is not made = of   steel or better goes into
>any part of the exhaust = system.  Particularly   gaskets and = nuts.
>
>
> =
>
>
> Guess I should have = passed that one along sooner.    Glad you got back =
>safely.  Good = job.
>
>
> =
>
>
> Dave   = Leonard
>
>
> On Sat, Jan 25, = 2014 at 5:14 PM, <downing.j@sbcglobal.net> = wrote:
>
>
>
>= ; =
>
>
>  &= nbsp;
> 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
>
>
= >
> =
>
>
> = Thanks for keeping us all informed , helps us all to = make     sure we look
>for often simple = overlooked = areas.
>
>    > =
>
>
> = Cheers
>
>    > Christian =
>
>
> = Renises 13 b rv7
>
> Sent from my     = iPad
>
>
&= gt;
> On 26/01/2014, at 3:17     AM, shipchief@aol.com = wrote:
>
>    &nb= sp;
>
>  =
> During the = 8th       flight of my RV8 with 13B Turbo, = I experienced an
>exhaust leak 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 = should       have know better, as the = temperature at the
>turbo outlet, under = the       insulation is much = higher.
>
>  &n= bsp;
> The brass = nuts       softened and deformed into a = flange face at the washer!
>Once the = tension       was gone, the heat & = vibration did the       = rest.
>
>  &nbs= p;
> The exhaust = gasket       blew where the gap was = widest, at the = top.
>
>   = ;
> The escaping = heat       burned thru the insulating = jacket and the stick on =
>reflective       aluminum. Then = the fiberglass cowl charred, I smelled =
>      that!
>  &nbs= p;
>
> = 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 ground = without       = incident.
>
>  =
> I'm = disassembling       it now, looks like I = need 4 high temperature lock
>nuts and 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 cowl, = which       might be in the form of an = aluminum access =
>      hatch.
>
> =
>
>
>
>
>
> =
> =

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