Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Wed, 26 Jan 2005 14:57:15 -0500 Message-ID: X-Original-Return-Path: Received: from systems3.net ([68.14.236.16] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP-TLS id 623574 for lml@lancaironline.net; Wed, 26 Jan 2005 14:44:25 -0500 Received-SPF: none receiver=logan.com; client-ip=68.14.236.16; envelope-from=cberland@systems3.net Received: from systems0d3b724 ([192.168.1.81]) by systems3.net (8.13.1/8.13.1/Debian-12) with SMTP id j0QJhthr025982 for ; Wed, 26 Jan 2005 12:43:55 -0700 X-Original-Message-ID: <010801c503de$a496daa0$5101a8c0@systems0d3b724> From: "Craig Berland" X-Original-To: "Lancair Mail List" Subject: [LML] Re: Plugs and Mags X-Original-Date: Wed, 26 Jan 2005 12:38:37 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0105_01C503A3.F522D360" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-Virus-Scanned: clamd / ClamAV version 0.75-1, clamav-milter version 0.75c on linux X-Virus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0105_01C503A3.F522D360 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Charlie K wrote: I had several (three to be exact) when over 500 hours,=20 that I would discover a mag drop that traced to a individual plug which = had=20 a cracked insulator. No other indications anywhere of=20 detonation/mechanical/dropped plugs during its history. Can it be that = the=20 porcelain becomes more brittle or soft or??? Any ideas?? During my General Motors Engineering days, broken plugs were an issue. = Tests were run and we found most mechanics over torqued spark plugs and = that plugs that were spec'd to be torqued to 19 ft lbs would fracture = the electrode when torqued to 29 ft lbs. When the electrode fractures, = the plug is junk and also it is a lot easier to break the ceramic if the = electode is fractured. Since then, I always use a torque wrench to = install plugs. ------=_NextPart_000_0105_01C503A3.F522D360 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Charlie K wrote:
 I had several (three to be exact) when over 500 hours, =
that I=20 would discover a mag drop that traced to a individual plug which had =
a=20 cracked insulator. No other indications anywhere of=20
detonation/mechanical/dropped plugs during its history.  Can it = be that=20 the
porcelain becomes more brittle or soft or???  Any = ideas??
During my General Motors = Engineering days,=20 broken plugs were an issue. Tests were run and we found most mechanics = over=20 torqued spark plugs and that plugs that were spec'd to be torqued to 19 = ft lbs=20 would fracture the electrode when torqued to 29 ft lbs. When the = electrode=20 fractures, the plug is junk and also it is a lot easier to break = the=20 ceramic if the electode is fractured. Since then, I always use a torque = wrench=20 to install plugs.
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