X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 29 Nov 2013 18:52:24 -0500 Message-ID: X-Original-Return-Path: Received: from mail-qa0-f52.google.com ([209.85.216.52] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6619225 for lml@lancaironline.net; Fri, 29 Nov 2013 12:45:49 -0500 Received-SPF: none receiver=logan.com; client-ip=209.85.216.52; envelope-from=james@seilbach.com Received: by mail-qa0-f52.google.com with SMTP id k4so2096339qaq.4 for ; Fri, 29 Nov 2013 09:45:15 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:date:message-id:in-reply-to :references:from:to:subject:content-type; bh=QVnWMOyOxOJSBCcYTjT800LaFCCHoqlCheEB3dfLI0k=; b=mqhtYkI4iMQXO27oYjitzAdQ1LPDOwdm9kI0fQSPqp8nwdKOsUjj5UuwhUzKuJ1JCa 5rQmjDONFyTsp+hAG1EIgmb70Cclty3uxqWEslgYqzGjZRGS+9oSMchtzmGQv50k5wfu Zf0a577uLsj1lTXJ1PHSWHj1O+TaOUFKENn3kGgj+ZFK8pMVqZ6UtfRRZjql8mRk2b6h VrLipPO8uCcn1Ht9eQAO0bBSkD3jT8OuAJN9LaLlUul9fNR010oCaBa7WNFVC1LL2qx7 K0YYstOUKoEdnI8A2kGW5ykcLek7ZJ+oIqJ8JLFaJ0CuQY+PcQ8LR5EMue4pdUeSkLOz 1Qeg== X-Gm-Message-State: ALoCoQnZM5jdQjTnBWLxpElPYSj4sHrd/tzEJF87dKIt2evteKW6cvQW4XIG/H93+7F/sYqBvst0 X-Received: by 10.49.28.226 with SMTP id e2mr47982427qeh.80.1385747115440; Fri, 29 Nov 2013 09:45:15 -0800 (PST) X-Original-Return-Path: Received: from [127.0.0.1] (ec2-54-235-159-154.compute-1.amazonaws.com. [54.235.159.154]) by mx.google.com with ESMTPSA id j4sm8577779qan.4.2013.11.29.09.45.14 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 29 Nov 2013 09:45:14 -0800 (PST) MIME-Version: 1.0 X-Mailer: Nodemailer (0.5.0; +http://www.nodemailer.com/) X-Original-Date: Fri, 29 Nov 2013 09:45:14 -0800 (PST) X-Original-Message-Id: <1385747113969.22ae0d7d@Nodemailer> In-Reply-To: References: X-Orchestra-Oid: 810D86B5-FDCF-4560-BB5A-6D81EED5B0A6 X-Orchestra-Sig: 7a94e7eda10ed195f29c55bef734bedaa9e87ba8 X-Orchestra-Thrid: TE48EAAD9-896B-4AB0-A843-99A798075A25_1452442518248502587 X-Orchestra-Thrid-Sig: b85814ca9e5aebfbaca1ac4e15aecd811c4208bd X-Orchestra-Account: f41d46505927c05022a316da4d9e641e52866023 From: james@seilbach.com X-Original-To: "Lancair Mailing List" Subject: Re: [LML] Re: [LNC2] Lycoming Exhaust Flange Nuts Content-Type: multipart/alternative; boundary="----Nodemailer-0.5.0-?=_1-1385747114726" ------Nodemailer-0.5.0-?=_1-1385747114726 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Mon, Nov 25, 2013 at 6:03 AM, Chris Zavatson wrote: > John, > Attached is a photo of the socket I use for that buried exhaust nut.= =C2=A0 Even though the wall thickness is very thin I can reach full = torque=C2=A0on the nuts. > =C2=A0 > Chris Zavatson > N91CZ > 360std > http://www.n91cz.net/ > =C2=A0 > On Friday, November 22, 2013 1:54 PM, John Cooper wrote: >=20=20=20 > The inboard nut securing the crossover exhaust flange on the #2 cylinder = is pretty much impossible to loosen or tighten with any tool known to = mankind. The exhaust pipe itself bends right over the stud so the flange = has to be lowered just to get the nut started. On the back (inboard) side, = the inter-cylinder baffles are right up against the nut. There's no access = at all from the forward of the aircraft because the cylinder fins are right= there. On the aft side, both the oil drainback line and intake tube must = be removed to have any chance of getting a tool in there and the stud from = the #4 cylinder intake leaves little room to swing a wrench. Here's a photo= of the tool I custom made to remove that one nut. The open area on the = wrench was necessary because the 5/16-18 UNC Lycoming exhaust nut was = almost right up against the exhaust pipe and a standard box wrench wouldn't= fit in between the nut and the pipe. Neither would a standard open end = wrench.=20 > That worked OK to remove the nut, although I could only unscrew it > half-a-flat at a time. It was a tedious process. > After having some AD work done on my O-290-D2, the engine is back on > the mounts and I'm now in the process of reinstalling the crossover > exhaust. I used the custom tool (above) to tighten the exhaust > flange nut half-a-flat at a time (again), but the tool wouldn't > torque it; It was too weak in that direction and tended to open up > and slip. So now I'm going to have to weld up some kind of stronger > tool which will fit in there, or use another kind of nut > altogether...which brings me to: > Has anybody used 12 pt. reduced-dimension nuts on their exhaust > flanges=3F I was surprised that they were even available with course > threads, but href=3D=22http://www.summitracing.com/parts/arp-401-8303/overview/=22= >Summit Racing carries them in stainless steel with coarse threads = (photo at link). I ordered 8 of these today which I intend to use on my = exhaust flanges. They take a 3/8=22 wrench which I am confident will have = enough clearance to be able to get back behind the exhaust pipe where a = 1/2=22 wrench won't fit. These are not lock-nuts so I'll still use a split = lock washer underneath. Any comments on this plan would be appreciated. > One other thing I learned in this ordeal: 5/16-18 Lycoming =22exhaust > flange nuts=22 take a 1/2=22 wrench, whereas =22standard=22 5/16-18 = nuts > take a 9/16=22 wrench. Don't ask me how I know this... ------Nodemailer-0.5.0-?=_1-1385747114726 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

On Mon, Nov 25, 2013 at 6:03 AM= , Chris Zavatson <chris=5Fzavatson@yahoo.= com> wrote:

John,
Attached is a photo of the socket I use for that buried exhaust = nut.=C2=A0 Even though the wall thickness is very thin I can reach full = torque=C2=A0on the nuts.
=C2=A0
Chris Zavatson
N91CZ
360std
=C2=A0
=

On= Friday, November 22, 2013 1:54 PM, John Cooper <snopercod@comporium.net> wrote:
=20=20 =20=20=20=20 =20=20
The inboard nut securing the crossover exhaust flange on the #2 cylinder is pretty much impossible to loosen or tighten with any tool known to mankind. The exhaust pipe itself bends right over the stud so the flange has to be lowered just to get the nut started. On the back (inboard) side, the inter-cylinder baffles are right up against the nut. There's no access at all from the forward of the aircraft because the cylinder fins are right there. On the aft side, both the oil drainback line and intake tube must be removed to have any chance of getting a tool in there and the stud from the #4 cylinder intake leaves little room to swing a wrench. Here's a photo of the tool I custom made to remove that one nut. The open area on the wrench was necessary because the 5/16-18 UNC Lycoming exhaust nut was almost right up against the exhaust pipe and a standard box wrench wouldn't fit in between the nut and the pipe. Neither would a standard open end wrench.

<Tran= sformed=5FLancair exh stack removal 005.JPG>


That worked OK to remove the nut, although I could only unscrew it half-a-flat at a time. It was a tedious process.

After having some AD work done on my O-290-D2, the engine is back on the mounts and I'm now in the process of reinstalling the crossover exhaust. I used the custom tool (above) to tighten the exhaust flange nut half-a-flat at a time (again), but the tool wouldn't torque it; It was too weak in that direction and tended to open up and slip. So now I'm going to have to weld up some kind of stronger tool which will fit in there, or use another kind of nut altogether...which brings me to:

Has anybody used 12 pt. reduced-dimension nuts on their exhaust flanges=3F I was surprised that they were even available with course threads, but <a href=3D=22http://www.summitracing.com/parts/arp-401-8303/over= view/=22>Summit Racing</a> carries them in stainless steel with coarse threads (photo at link). I ordered 8 of these today which I intend to use on my exhaust flanges. They take a 3/8=22 wrench which I am confident will have enough clearance to be able to get back behind the exhaust pipe where a 1/2=22 wrench won't fit. These are not lock-nuts so I'll still use a split lock washer underneath. Any comments on this plan would be appreciated.

One other thing I learned in this ordeal: 5/16-18 Lycoming =22exhaust flange nuts=22 take a 1/2=22 wrench, whereas =22standard=22 5/16-18 = nuts take a 9/16=22 wrench. Don't ask me how I know this...


<exhaust nut socket-sm.jpg>

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