X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "Marc Wiese cardmarc@charter.net" Received: from pmg.Logan.com ([207.170.160.161] verified) by logan.com (CommuniGate Pro SMTP 6.4.0) with ESMTPS id 3783350 for flyrotary@lancaironline.net; Fri, 10 Jan 2025 11:33:02 -0500 Received: from pmg.Logan.com (localhost [127.0.0.1]) by pmg.Logan.com (Proxmox) with ESMTP id 9BBA92A257 for ; Fri, 10 Jan 2025 11:33:02 -0500 (EST) Received-SPF: pass (charter.net: 47.43.20.33 is authorized to use 'cardmarc@charter.net' in 'mfrom' identity (mechanism 'ip4:47.43.20.0/24' matched)) receiver=pmg.Logan.com; identity=mailfrom; envelope-from="cardmarc@charter.net"; helo=impout009.msg.chrl.nc.charter.net; client-ip=47.43.20.33 Received: from impout009.msg.chrl.nc.charter.net (impout009aa.msg.chrl.nc.charter.net [47.43.20.33]) by pmg.Logan.com (Proxmox) with ESMTPS for ; Fri, 10 Jan 2025 11:33:01 -0500 (EST) Received: from smtpclient.apple ([68.184.182.131]) by cmsmtp with ESMTPA id WHwMtxveMq1U6WHwMtz2EZ; Fri, 10 Jan 2025 16:32:55 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=charter.net; s=c20240129; t=1736526775; bh=5yiWZVL47LegvALf5Puv809VA1SsvSdUpSOBlyQOUTo=; h=From:Subject:Date:References:In-Reply-To:To; b=vAu+6rJZC/X96xlYA0p76qgGHdri0UB4x3Lyl5tD58c2RNEVZhCQAnKRX6q9AThrt tgD57/sNEbklym6w6rW1TKzMG3jt9vIxtGBoszTqnX6XqD3kiRXF8xg4djmAYvgQqR 2K3O0fQ26fweSELfkrPfwqcB7jOKHMSIxhIfEcjUOfhtoGHoxUYdsYlEf+VBTHseu+ fz1xyE61JDmlrQ1XmRgeljMC07nFwjnwjudc8Jlg8Pree4XPIKHVVyfzx/QWLZ8wqe Fg+CREkezGMqmXVDvmqC7LAg6PYY41S5/Rb2EX304ORKnRpvRHOZiDNzndlmgnupwL Ny1CRBGJCHT7w== Authentication-Results: charter.net; auth=pass (PLAIN) smtp.auth=cardmarc@charter.net X-Authority-Analysis: v=2.4 cv=OJ4h3zaB c=1 sm=1 tr=0 ts=67814bb7 a=qoXC88jkgkm1v/IAzpf30Q==:117 a=qoXC88jkgkm1v/IAzpf30Q==:17 a=C_IRinGWAAAA:8 a=Ia-xEzejAAAA:8 a=pGLkceISAAAA:8 a=eRLigfuSAAAA:8 a=hOpmn2quAAAA:8 a=7g1VtSJxAAAA:8 a=Y37JtY3EJ7EFoR7NgiUA:9 a=x-KbKg3E5C7cOR0D:21 a=_W_S_7VecoQA:10 a=lqcHg5cX4UMA:10 a=QEXdDO2ut3YA:10 a=Qa1je4BO31QA:10 a=gvSQh4r-fQ0A:10 a=Urk15JJjZg1Xo0ryW_k8:22 a=BfhXYjFvZD4iae-mNffo:22 a=grOzbf7U_OpcSX4AJOnl:22 Content-Type: multipart/alternative; boundary=Apple-Mail-E5819B2C-51EE-4678-BBD8-ACDC86D94CA1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) Subject: Re: [FlyRotary] Re: Flexplate cracks Date: Fri, 10 Jan 2025 10:32:44 -0600 Message-Id: References: In-Reply-To: To: flyrotary@lancaironline.net X-Mailer: iPhone Mail (22B91) X-CMAE-Envelope: MS4xfFn3B4WCl15FGpItBdNOVMf24YS3kLKAzdAVKWxW/3z5e6wuokT6J/No5zxW0WfuiV/N4cYpMPccp6XsYfJI7Dho7pFhb13XMu5ThInFV9F4bDjPB695 iQT+X0FvQTynCRM3tkJ2ltBDbIAZANG6Rj8pftZbAfit/tBy/CQb5Ad2YPtL5yMx3zJ9ozHfwU9e3UK3h97SU91wHJh8DFJ14F8= X-SPAM-LEVEL: Spam detection results: 0 AWL -0.707 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DKIM_SIGNED 0.1 Message has a DKIM or DK signature, not necessarily valid DKIM_VALID -0.1 Message has at least one valid DKIM or DK signature DKIM_VALID_AU -0.1 Message has a valid DKIM or DK signature from author's domain DKIM_VALID_EF -0.1 Message has a valid DKIM or DK signature from envelope-from domain DMARC_MISSING 0.1 Missing DMARC policy FREEMAIL_FROM 0.001 Sender email is commonly abused enduser mail provider HTML_MESSAGE 0.001 HTML included in message KAM_MXURI 1.5 URI begins with a mail exchange prefix, i.e. mx.[...] MIME_HTML_ONLY 0.1 Message only has text/html MIME parts MIME_QP_LONG_LINE 0.001 Quoted-printable line longer than 76 chars MPART_ALT_DIFF 0.79 HTML and text parts are different RCVD_IN_DNSWL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to DNSWL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#DnsBlocklists-dnsbl-block for more information. RCVD_IN_VALIDITY_CERTIFIED_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_RPBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_SAFE_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [flyrotary.com,lancaironline.net] WEIRD_PORT 0.001 Uses non-standard port number for HTTP --Apple-Mail-E5819B2C-51EE-4678-BBD8-ACDC86D94CA1 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable I have to say I=E2=80=99ve got several plat= es from 1-20bs, 3-13brewTt, and 2-RX8=E2=80=99s (series1) that show no evide= nce of cracking, fwiw. 
M
Sent from my iPhone

On Jan 10, 2025, at 8:36=E2=80=AFAM, Charlie England ceengland7= @gmail.com <flyrotary@lancaironline.net> wrote:

=EF=BB=BF
I'm pre= tty sure David's got it right. I've got a flexplate that's never been run on= an aviation engine that's cracked. I really think it's a combination of slo= ppy design and 'good enough' manufacturing. Look carefully at the light= ening holes where the cracks usually start. the holes are punched, with no p= ost-treatment to smooth the sharp edges. Then the sheet is stamped putting s= tress on the metal around the holes. Perfect recipe for cracks.

Len Hanover (you still here, Len?) once= speculated that the scrap yards were cracking them by sitting the engines d= own on the flexplates, but I think they're just cracking from mfg-induced st= resses and vibration; even in the car.

Charlie

On Fri, Jan 10, 2025 at 5:03=E2= =80=AFAM David COOK hoursaway1@com= cast.net <flyrotary@la= ncaironline.net> wrote:
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Automotive tech for 4= 0 years, 25 years Cadillac. I saw quite a few cracked flexplates. Why, some w= ere self diagnosed, corrosion between starter and eng. block changed geometr= y, witness marks that cust. would try to start a running eng., loose torque c= onverter bolts, loose trans to eng. bolts, wrong starter held on with one bo= lt. When I was seeking a Mazda RX7 flexplate for out project, first three we= re cracked right out of the cars. I think our starter is shimmed out 1/16", o= riginal RWS PSRU-RD1-B, original starter position. 
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On 01/10/2025 4:44 AM EST Le Roux Breytenbach breytenbachleroux@gmail.com <<= a href=3D"mailto:flyrotary@lancaironline.net" target=3D"_blank">flyrotary@la= ncaironline.net> wrote:
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What i can rember was this also a topic on the late Paul L group d= iscussion.=20
Maybe Dave Leonard can chime in - think more that it was gyroscopic forc= es that craked the plates
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Maybe i can find the photos and topic in my old mails
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Sent from my iPhone=20
Le Roux Breytenbach 
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On 10 Jan 2025, at 08:13, Andrew Martin andrew@martinag.com.au <flyrotary@lancaironline.ne= t> wrote:

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Maybe some of the cracking flexplates are resulting from starting is= sues, the starter motor can hammer the ring gear if not meshing correctly or= if engine misfires on start. may explain why so many flexplates come pre-cr= acked from the wreckers.
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Andrew
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On Fri, 10 Jan 2025 at 11:32, Stephen Izett stephen.izett@gmail.com <flyrotary@lancairo= nline.net> wrote:
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Hi M

I was wondering the same thing.=20

What I discovered first of all was that flex plates are designed= to flex (funny that) and cracking is not limited to our setup.=20
There are companies that specialise in stronger flex plates, par= ticularly for modified and higher horsepower engines.

Since our engines are being used at a higher horsepower per unit= time and therefore higher stress (assumption) perhaps our setup could be li= kened to race applications.
But then our hours of use would be significantly lower (assumpti= on) than an average vehicle, but perhaps not a race application.
Is the cracking we are seeing consistent with race applications?= But they dont race automatics, do they?

So my take on this is that perhaps the flexing of the plate in o= ur setup is to some extent higher than OEM.

Our options seem to be:
1. Replacing the OEM flex plate with a stronger part. Steve B be= ing the latest going down that track and in his case also removing the rubbe= r isolation in the process.
2. Connect direct to the eccentric shaft and therefore taking th= e stress off the Flex Plate doing away with the damping mechanism which Trac= y did, and perhaps is still doing. Would be real nice to know.

Like M, I would appreciate hearing what others know or are think= ing or doing.

Steve Izett












> On 10 Jan 2025, at 2:15=E2=80=AFam, Marc Wiese cardmarc@char= ter.net <flyrotary@lancaironline.net> wrote:
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> Has the cause of these cracks been uncovered, and if so, wh= at is the current thinking on it? An AL racing plate?
> M
> Sent from my iPhone
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>> On Jan 9, 2025, at 1:31=E2=80=AFAM, Steven W. Boese SBoese@uwy= o.edu <flyrotary@lancaironline.net> wrote:
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>> Steve,
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>> I didn=E2=80=99t see the cracks prior to disassembly an= d doubt that they could have been seen on the counterweight side very well -= if at all- when assembled.
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>> I replaced the Flexplate with a steel flywheel about a y= ear ago.  Since then, I replaced the four rubber dampers with machined a= luminum discs giving a solid connection and then dynamically balanced the sy= stem.  This was done because maintaining a dynamic balance wasn=E2=80=99= t possible with the dampers.  Only a few hours of flight have occurred i= n this configuration so far and there has been no indication of problems res= ulting from this change.
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>> Steve Boese
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>>> On Jan 8, 2025, at 11:03=E2=80=AFPM, Stephen Izett <= a href=3D"mailto:stephen.izett@gmail.com" rel=3D"noopener" target=3D"_blank"= >stephen.izett@gmail.com <flyrotary@lancaironline.net> w= rote:
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>>> =E2=97=86 This message was sent from a non-UWYO add= ress. Please exercise caution when clicking links or opening attachments fro= m external sources.
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>>> Hi Steve
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>>> Is this recent then?
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>>> I=E2=80=99m not able to get to my aircraft at prese= nt to check my flex plate which has probably seen 50 hours of service.
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>>> Was it possible to see these cracks assembled?
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>>> I would appreciate your reflections on Tracys latte= r choice to remove the damper, and particularly when using a timber/glass pr= op such as an MT.
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>>> It would be great to have an update and current inf= o from Tracy regarding his no damper hours if anyone can contact him.
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>>> Very helpful, thanks again Steve
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>>> Steve
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>> --
>> Homepage:  http://www.flyrotary.com/
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> --
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