X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Sun, 13 Aug 2006 15:32:26 -0400 Message-ID: X-Original-Return-Path: Received: from smtp108.sbc.mail.mud.yahoo.com ([68.142.198.207] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with SMTP id 1319932 for lml@lancaironline.net; Sat, 12 Aug 2006 15:12:26 -0400 Received-SPF: none receiver=logan.com; client-ip=68.142.198.207; envelope-from=elippse@sbcglobal.net Received: (qmail 88147 invoked from network); 12 Aug 2006 19:11:41 -0000 Received: from unknown (HELO Computerroom) (elippse@sbcglobal.net@75.15.131.252 with login) by smtp108.sbc.mail.mud.yahoo.com with SMTP; 12 Aug 2006 19:11:41 -0000 X-Original-Message-ID: <000901c6be43$26b9b9b0$fc830f4b@Computerroom> From: "Paul Lipps" X-Original-To: "Marv Kaye" Subject: EI sparks X-Original-Date: Sat, 12 Aug 2006 12:11:43 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C6BE08.7954BC50" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C6BE08.7954BC50 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable On a waste-spark system, two plugs, 180 apart in the firing order, = fire in series; one just before the top of the exhaust stroke, and one = near the top of the compression stroke. So for all practical purposes, = they fire simultaneously! On the Lycomings, it's 1&2, 3&4, and 5&6 on = the 6 cyl. So if cylinder 1 is normal and 2 is not, for instance, it = would indicate possible breakdown in the #2 wiring, a fouled plug, or = bad connections, as Scotty pointed out. The coil transformer secondary = is totally isolated from ground. The voltage leaves one terminal, jumps = a plug gap, travels across the engine, jumps the other gap, then returns = to the other coil terminal. It's a good idea to keep the high-voltage = wiring mounted away from any metal, as there is capacitive coupling from = the coil to ground. This coupling, along with capacitive coupling from = the HV wiring to ground, can form a capacitive voltage divider which = reduces the output. Excess wiring capacitance, acting in shunt with the = secondary resistance, can create a voltage drop which reduces peak = voltage and slows rise time. On my Lancair, I use non-metallic standoffs = where possible to keep the HV wires away from the engine. It doesn't = have to be a lot; 1/2" works. It's also prudent to keep HV wiring from = closely parallelling other wires so as not to induce voltage transients = in them; they may be part of sensitive circuitry. These considerations = apply to all waste-spark systems, not just LSE! ------=_NextPart_000_0006_01C6BE08.7954BC50 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

On a waste-spark system, two plugs, 180 = apart in=20 the firing order, fire in series; one just before the top of the = exhaust=20 stroke, and one near the top of the compression stroke. So for all = practical=20 purposes, they fire simultaneously! On the Lycomings, it's 1&2, = 3&4, and 5&6 on the 6 cyl. So if cylinder 1 is normal = and 2 is=20 not, for instance, it would indicate possible breakdown in the = #2 wiring, a=20 fouled plug, or bad connections, as Scotty pointed out. The coil = transformer=20 secondary is totally isolated from ground. The voltage leaves one = terminal,=20 jumps a plug gap, travels across the engine, jumps the other gap, then = returns=20 to the other coil terminal. It's a good idea to keep the high-voltage = wiring=20 mounted away from any metal, as there is capacitive coupling from the = coil to=20 ground. This coupling, along with capacitive coupling from the HV wiring = to=20 ground, can form a capacitive voltage divider which reduces the = output.=20 Excess wiring capacitance, acting in shunt with the secondary = resistance,=20 can create a voltage drop which reduces peak voltage and slows rise = time.=20 On my Lancair, I use non-metallic standoffs where possible to keep the = HV wires=20 away from the engine. It doesn't have to be a lot; 1/2" works. It's = also=20 prudent to keep HV wiring from closely parallelling other wires so as = not to=20 induce voltage transients in them; they may be part of sensitive = circuitry.=20 These considerations apply to all waste-spark systems, not just=20 LSE!

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