X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2611492 for flyrotary@lancaironline.net; Mon, 24 Dec 2007 00:54:07 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao102.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20071224055327.VPHL24689.fed1rmmtao102.cox.net@fed1rmimpo03.cox.net> for ; Mon, 24 Dec 2007 00:53:27 -0500 Received: from BigAl ([72.192.143.193]) by fed1rmimpo03.cox.net with bizsmtp id UVt71Y0014AaN600000000; Mon, 24 Dec 2007 00:53:07 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Spark Plugs Date: Sun, 23 Dec 2007 21:54:20 -0800 Message-ID: <000001c845f1$6d487880$6401a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C845AE.5F253880" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C845AE.5F253880 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable In olden times we could do a clean cut, read the plugs and re-jet up or = down depending. But then motor fuel had lots of lead in it and would give you = a color. A clean cut was from at temperature an a full throttle load, = ignition off and clutch in. So you were looking at the color of an operational = plug. Today we have no lead, and no colors to look at. So nobody looks at = plugs anymore. If you want to check for too high a heat range, check for = cement boil around the center electrode, and or flecks of porcelain missing. =20 The light color with a plume of black is typical but usually the leading plug will just look dirty. Even the end of the shell will be black. = These plugs are not the coldest plugs you can get. So long as the cement is staying out of sight, these are fine. You use a higher heat range if you = get fouling below full throttle. You cannot hurt an engine with too low a = heat range. You can destroy it with too high a heat range. I use the coldest = heat range made by NGK and they don't foul. R6725-11.5 $25.00 each. =20 Lynn E. Hanover Thanks, Lynn. I'll probably run these another 20 hours and check them again. =20 Interesting; I buy these on-line from Rock Auto in boxes of 4 for $5 = each. The local parts stores want about double that. I found them selling on e-bay for $12. Hum-m-m, looks like a business opportunity. Al ------=_NextPart_000_0001_01C845AE.5F253880 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

In olden times we could do a clean cut, read the plugs and = re-jet up or down depending. But then motor fuel had lots of lead in it and = would give you a color. A clean cut was from at temperature an a full throttle = load, ignition off and clutch in. So you were looking at the color of an = operational plug.

Today we have no lead, and no colors to look at. So nobody looks at plugs = anymore. If you want to check for too high a heat range, check for cement boil = around the center electrode, and or flecks of porcelain missing.

The light color with a plume of black is typical but usually the leading = plug will just look dirty. Even the end of the shell will be black. These plugs = are not the coldest plugs you can get. So long as the cement is staying out of = sight, these are fine. You use a higher heat range if you get = fouling below full throttle. You cannot hurt an engine with too low a heat range. You can = destroy it with too high a heat range. I use the coldest heat range made by NGK = and they don't foul. R6725-11.5 $25.00 each.

Lynn E. Hanover

Thanks, Lynn. = I’ll probably run these another 20 hours and check them again. =

Interesting; I buy these on-line = from Rock Auto in boxes of 4 for $5 each. The local parts stores want about = double that. I found them selling on e-bay for $12. Hum-m-m, looks = like a business opportunity.

Al

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