X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 03 Jan 2011 08:35:34 -0500 Message-ID: X-Original-Return-Path: Received: from mail-iy0-f180.google.com ([209.85.210.180] verified) by logan.com (CommuniGate Pro SMTP 5.3.11) with ESMTP id 4661897 for lml@lancaironline.net; Sun, 02 Jan 2011 22:42:47 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.210.180; envelope-from=donkarich@gmail.com Received: by iyi12 with SMTP id 12so15478999iyi.25 for ; Sun, 02 Jan 2011 19:42:13 -0800 (PST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=F+s9KfB2SQ89RfymsZb9mun+qKcfqtV6C4+GSTXZ/MbMqgbYYbXhbQ19pLjmKAfEQF PFRSPQZqD25iL+kbRgLRlu+nLqScWKPLD+inUR7/RvQmJOTWZkOF/BAILRiGmMEM19eK /awiW7mNjE7KTR+dh4aXHzvpjtDvbiW7cZEPc= MIME-Version: 1.0 Received: by 10.231.59.77 with SMTP id k13mr3722605ibh.188.1294026132910; Sun, 02 Jan 2011 19:42:12 -0800 (PST) Received: by 10.231.149.8 with HTTP; Sun, 2 Jan 2011 19:42:12 -0800 (PST) In-Reply-To: References: X-Original-Date: Sun, 2 Jan 2011 19:42:12 -0800 X-Original-Message-ID: Subject: Re: [LML] Re: spark plug gap From: Don Karich X-Original-To: Lancair Mailing List Content-Type: multipart/alternative; boundary=001485e9a94efb72900498e8ef78 --001485e9a94efb72900498e8ef78 Content-Type: text/plain; charset=ISO-8859-1 another issue to consider is the direction of electron flow. I was taught to rotate the plugs on servicing. I was told to advance each plug on reinsertion one hole. as example from cylinder 1 top to cylinder 3 bottom. then 3 top to 5 bottom etc.. etc. What does this accomplish? It reverses electron flow from center to outer to outer to central thus reducing the wear one the center. ie it ovals out slower prolonging the life of the plug. Only other tip is to be sure and use antisieze (One small drop on threads and a torq wrench to accurately tighten to 35 foot lbs. (important) On Thu, Dec 30, 2010 at 10:10 PM, REHBINC wrote: > Chris, > > A bigger gap requires more voltage to arc. This increases the load on the > rest of the ignition system. stray current losses will increase, insulation > may break down faster, etc. As long as there is sufficient voltage and > current, the bigger gap will result in a bigger spark and initiate a faster > start to the combustion event. The result is a little like advancing the > timing but without as much energy lost compressing the combusted gasses. > Perhaps a better analogy is the difference between operating on one plug > versus two. The spark plug will be a little hotter and could lead to pre > ignition/detonation issues. If the gap is too big, the current finds > somewhere else to go and the cylinder misfires. > > Smaller gap leads to cooler plugs, which could foul. Too small and the > spark doesn't consistently ignite the mixture and the cylinder misfires. > > Small differences within the specification probably won't make much > difference. If the plugs look a little cool, opening the gap to the max may > help a bit. As an old hot rodder, I would always open them up to the limit, > but errosion will lead to misfiring a little sooner. > > Magnetos make increased electrical energy as rpm increases as opposed to > electronic/points that make a reasonably uniform output until high rpm where > coil saturation starts to mess things up. Consequently, the magneto could be > a little more sensitive to large gaps at start up. > > Keeping the electrode edges nice and sharp greatly lowers the voltage > required to fire the plug. With the old fashioned ones, you could file the > center and ground electrodes flat after they had eroded and re gap them. > They would work as well as new as long as the insulators were still clean. > That is a little difficult on the fine wire types and the side electrode > styles. > > Rob > > In a message dated 12/30/10 20:10:05 Eastern Standard Time, > chris_zavatson@yahoo.com writes: > > I have a question for all the engine experts on the list. > What are the pros and cons to wider vs. smaller gap in our spark plugs. > The given range by Champion etc. must balance several parameters. I am > trying to get a feel for why one would choose to be on one end of the range > over the other. Also. what might be expected outside the specified range, > too small or too large. > I am assuming magnetos here. I imagine the answer might change with EI. > thanks, > Chris Zavatson > > > --001485e9a94efb72900498e8ef78 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable another issue to consider is the direction of electron flow. I was taught t= o rotate the plugs on servicing. I was told to advance each plug on reinser= tion one hole. as example from cylinder 1 top to cylinder 3 bottom. then 3 = top to 5 bottom etc.. etc.=A0 What does this accomplish? It reverses electr= on flow from center to outer to outer to central thus reducing the wear one= the center. ie it ovals out slower prolonging the life of the plug. Only o= ther tip is to be sure and use antisieze (One small drop on threads and a t= orq wrench to accurately tighten to 35 foot lbs. (important)

On Thu, Dec 30, 2010 at 10:10 PM, REHBINC <rehbinc@aol.com><= /span> wrote:
Chris,
=A0
A bigger gap requires more voltage to = arc. This increases the load on the rest of the ignition system. stray curr= ent losses will increase, insulation may break down faster, etc. As long as= there is sufficient voltage and current, the bigger gap will result in a b= igger spark and initiate a faster start to the combustion event. The result= is a little like advancing the timing but without as much energy lost comp= ressing the combusted gasses. Perhaps a better analogy is the difference be= tween operating on one plug versus two.=A0The spark plug will be=A0a little= hotter and could lead to pre ignition/detonation issues. If the gap is too= big, the current finds somewhere else to go and the cylinder misfires.
=A0
Smaller gap leads to cooler plugs, whi= ch could foul. Too small and the spark doesn't consistently ignite the = mixture and the cylinder misfires.
=A0
Small differences within the specifica= tion probably won't make much difference. If the plugs look a little co= ol, opening the gap to the max may help a bit. As an old hot rodder, I woul= d always open them up to the limit, but errosion will lead to misfiring a l= ittle sooner.
=A0
Magnetos make increased electrical ene= rgy as rpm increases as opposed to electronic/points that make a reasonably= uniform output until high rpm where coil saturation starts to mess things = up. Consequently, the magneto could be a little more sensitive to large gap= s at start up.
=A0
Keeping the electrode edges nice and s= harp greatly lowers the voltage required to fire the plug. With the old fas= hioned ones, you could file the center and ground electrodes flat after the= y had eroded and re gap them. They would work as well as new=A0as long as t= he insulators were still clean. That is a little difficult on the fine wire= types and the side electrode styles.
=A0
Rob
=A0
In a message dated 12/30/10 20:10:05 Eastern Standard Time, chris_zavatson@yahoo.co= m writes:
I have a question for all the engine experts on the list.=A0
What are the pros and cons to wider vs. smaller gap in our spark plugs= .=A0 The given range by Champion etc. must balance several parameters.=A0 I= am trying to get a feel for why one would choose to be on one end of the r= ange over the other.=A0 Also. what might be expected outside the specified = range, too small or too large.
I am assuming magnetos here.=A0 I imagine the answer might change with= EI.
thanks,
Chris Zavatson

=A0

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