Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Thu, 28 Nov 2002 01:09:50 -0500 Message-ID: X-Original-Return-Path: Received: from ncsmtp02.ogw.rr.com ([24.93.67.83] verified) by logan.com (CommuniGate Pro SMTP 4.0.1) with ESMTP id 1887830 for flyrotary@lancaironline.net; Tue, 26 Nov 2002 21:01:16 -0500 Received: from mail5.carolina.rr.com (fe5 [24.93.67.52]) by ncsmtp02.ogw.rr.com (8.12.5/8.12.2) with ESMTP id gAR1xvvL018167 for ; Tue, 26 Nov 2002 21:00:53 -0500 (EST) Received: from o7y6b5 ([24.25.90.153]) by mail5.carolina.rr.com with Microsoft SMTPSVC(5.5.1877.757.75); Tue, 26 Nov 2002 20:59:54 -0500 X-Original-Message-ID: <001801c295b9$a3144c20$1702a8c0@WorkGroup> From: "Ed Anderson" X-Original-To: "flyrotary" Subject: Spark Plug Fouling X-Original-Date: Tue, 26 Nov 2002 21:06:08 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 After doing some reading about sparkplug fouling (reference to my 25hour average life using 100LL), I believe that the combination of carbon core suppression sparkplug wires AND a resistor sparkplug may be contributing to their short effective life. I just refitted my 13B with MAGNECOR Metallic Inductance EMI Suppressed Conductors. They seem to suppress any ignition noise in the radio as well as the carbon core ones. >From what I read, apparently the average inductive generated sparkplug pulse takes approx 100nsec rise time. If the sparkplug has carbon or lead fouling coating the ceramic cone this tends to provide a lower resistance path for the spark. As the leading edge of this slow? rising pulse starts to build the voltage is bled off by the lower resistance path which may prevent the pulse from rising to a voltage level necessary to jump the electrode gap. They used to make spark plugs that had a fairly large space gap in the center electrode wire inside the porcelain part of the plug. This prevented any voltage from getting to the cone/center electrode and prevented the "Bleed Off". Once the voltage build up sufficient to jump the space gap it had more than enough voltage to jump the electrode gap at the firing end. Also, this space gap apparently had the effect of causing the effective duration of the pulse to decrease from 100nsec to approx 10nsec. Due to these effects these type sparkplugs were fairly effective in firing a fouled plug, but alas apparently they are no longer made. This may also be part of the reason that some of the CDI type ignitions are more effective in firing fouled plugs (shorter pulse rise time which doesn't permit as much voltage to be bled off and the voltage is higher to begin with). So will let you know if this improves the plug life. Next is to get some no resistor sparkplugs from the motorcycle shop and try them out. Ed Anderson Matthews, NC RV-6A N494BW eanderson@carolina.rr.com