X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from aspensprings.uwyo.edu ([129.72.10.32] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTPS id 4488028 for flyrotary@lancaironline.net; Thu, 30 Sep 2010 16:41:06 -0400 Received-SPF: none receiver=logan.com; client-ip=129.72.10.32; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht2.uwyo.edu (ponyexpress-ht2.uwyo.edu [10.84.60.209]) by aspensprings.uwyo.edu (8.14.4/8.14.4) with ESMTP id o8UKeRu2014345 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Thu, 30 Sep 2010 14:40:27 -0600 (MDT) (envelope-from SBoese@uwyo.edu) Received: from ponyexpress-mb5.uwyo.edu ([fe80::9813:248c:2d68:a28b]) by ponyexpress-ht2 ([10.84.60.209]) with mapi; Thu, 30 Sep 2010 14:40:25 -0600 From: "Steven W. Boese" To: Rotary motors in aircraft Date: Thu, 30 Sep 2010 14:40:25 -0600 Subject: RE: [FlyRotary] Re: New SAG Theory Discussions of SAG Thread-Topic: [FlyRotary] Re: New SAG Theory Discussions of SAG Thread-Index: ActgtuRSip6+m1Z2Q+yYmzUnEkLKQgAJv5tA Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_E1AA3B1AF41D8049B1E3FBD5E225626004E2453FE4ponyexpressmb_" MIME-Version: 1.0 --_000_E1AA3B1AF41D8049B1E3FBD5E225626004E2453FE4ponyexpressmb_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, That's the way I see it too. The change in the thermal conductivity of the= electrode core (if it is indeed a factor) seems to take much longer to bec= ome a problem and may simply not be significant when 100LL is the predomina= nt fuel. The longevity of the plugs when not exposed to 100LL seems to sup= port this. Since I have found only the one plug with the large cavity in the copper co= re, it is not possible to draw general conclusions from this. This plug ma= y have suffered from a manufacturing defect. However, the less dramatic po= rosity development shown in the SEM photos is seen in all the older plugs a= nd is less likely to be anomalous. Steve Boese ________________________________ From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf Of = Ed Anderson [eanderson@carolina.rr.com] Sent: Thursday, September 30, 2010 9:46 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: New SAG Theory Discussions of SAG Thanks for the clarification, Steve However, that raises a new question. If the porosity is even a significan= t contributing factor to thermal cycling, I would expect the same thermal c= ycling deterioration with Mogas or 100LL - not certain why it would be diff= erent between the two? IF not significantly different, then that leaves th= e lead enhanced corrosion as the major culprit - at least that is the way i= t appears to me. Agree, regardless of cause - the answer is replace the plugs - however, if = you discover the colder plugs last longer - then that would permit me to re= duce my bushel basket storage of old spark plugs - cleaning (even if it wer= e possible) does not appear to be a option any longer {:>) Ed Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com --_000_E1AA3B1AF41D8049B1E3FBD5E225626004E2453FE4ponyexpressmb_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Ed,

That's the way I see it too. Th= e change in the thermal conductivity of the electrode core (if it is indeed= a factor) seems to take much longer to become a problem and may simply not= be significant when 100LL is the predominant fuel. The longevity of the plugs when not exposed to&nbs= p;100LL seems to support this.

Since I have found only the one = plug with the large cavity in the copper core, it is not possible to draw g= eneral conclusions from this. This plug may have suffered from a manu= facturing defect. However, the less dramatic porosity development shown in the SEM photos is seen in all th= e older plugs and is less likely to be anomalous.

Steve Boese

=

From: Rotary moto= rs in aircraft [flyrotary@lancaironline.net] On Behalf Of Ed Anderson [eand= erson@carolina.rr.com]
Sent: Thursday, September 30, 2010 9:46 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: New SAG Theory Discussions of SAG

Thanks for the clarification, Steve

However, that raises a new question. If&nbs= p;the porosity is even a significant contributing factor to= thermal cycling, I would expect the same thermal cycling deterioratio= n with Mogas or 100LL - not certain why it would be different between the two? IF not significantly different, then that leaves the lead e= nhanced corrosion as the major culprit - at least that is the way it appear= s to me.

Agree, regardless of cause - the answer is replac= e the plugs - however, if you discover the colder plugs last longer - then = that would permit me to reduce my bushel basket storage of old spark plugs = - cleaning (even if it were possible) does not appear to be a option any longer {:>)

Ed

Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

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