X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from qw-out-2122.google.com ([74.125.92.25] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3748820 for flyrotary@lancaironline.net; Wed, 08 Jul 2009 00:12:58 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.92.25; envelope-from=fluffysheap@gmail.com Received: by qw-out-2122.google.com with SMTP id 3so1939877qwe.25 for ; Tue, 07 Jul 2009 21:12:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=qHmzdWrDoQ/l5m7Qsu15gx38aqGi6qMI08rxAVAU48U=; b=NYmRe57OdqgG6M+vxdtKi8o/ZC7NGm/w7CJbyVVGo4fHm0jGUMTqWB7WHXCicexy1Y 7pWmC8obhmZAb2x4PhFrBp2IftoLK4Lbwz0WIyazhXKjhgQZ+K0iQm4391cAj0reeBlY dpm0TjfanEKfm9IP7KIIdtscVDDTGU7OvjL00= 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/ljwTT7Mfmlhcysq7Y4ZeTKb6HlObsNZ3hNdAsZO1aNmByf9nd8P8JDD3l8xMGMHa coi/YnPrRrAcY1Z5GmR05ttSSpywQx5cDpjbKqGy+meiz2BE1DOlCJBjCCyjyP0KULna frDyvvHHm+2nw1GpPfVgBGFoVBiC2dm6QsUng= MIME-Version: 1.0 Received: by 10.224.37.65 with SMTP id w1mr7398896qad.51.1247026342063; Tue, 07 Jul 2009 21:12:22 -0700 (PDT) In-Reply-To: References: Date: Tue, 7 Jul 2009 21:12:20 -0700 Message-ID: Subject: Re: [FlyRotary] SAG- Spark plugs From: William Wilson To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015175cdc6025081b046e29f206 --0015175cdc6025081b046e29f206 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit The '93-'95 have the same spark plug specified as the 2nd gens, both turbo and non - BUR9EQ/BUR7EQ. This is not really a surprise because, even though the car is faster, the engine still spends 99% of the time puttering along at 2800 RPM making 30 HP. I would tend to agree that a colder plug is probably better for aircraft use because of the sustained high RPM. On Tue, Jul 7, 2009 at 8:43 PM, Lynn Hanover wrote: > In a message dated 7/7/2009 3:22:56 P.M. Pacific Daylight Time, > bbradburry@bellsouth.net writes: > > Steve, > I hope Lynn chimes in here. He has seen a lot of plugs under a lot of > conditions. They look pitted to me. There seems nothing wrong with your > conditions. The only thing on the list would be too lean.?? > Someone is out there writing up a great response right now! :>) > Bill B > > That plug has been too hot. > > Stock Mazda plugs are rather cold in heat range by way of the guards around > the shell. The electrode runs a bit hotter than normal. Plug heat ranges are > determined by how far down the shell the porcelain touches. The longer the > heat path, the hotter the plug. > > Using car plugs in the aircraft application seems to be asking for trouble. > In the car on the freeway you use 2,600 RPM and 1/2 throttle, maybe 24 to 28 > HP. Not much of a challenge for a spark plug. But there is the > driver who will jump into his 95 twin turbo in LA and run out to LasVegas > at full tilt and expect to still have an engine when he gets there. And > usually he does. So, if I was to use a street plug in an aircraft, I would > use the 93-95 twin turbo plug, whatever that is. > > The aircraft application, less the 100LL fuel problem, is clearly a cold > racing plug with a conventional gap or close to it. > > Years ago when we started racing rotaries, Champion said to use the N-57G > Fine wire center with gold paladium plating and a conventional ground strap. > About 20% of the center wire is exposed in an end view. > > The N-57G and similar are discontinued and the N-82 series replaced it. The > shell is thinner and the porcelain is wider. Same fine wire center, no gold > anything. 20% of the wire exposed in an end view. > Both worked fine even with points and a Kettering coil. > > Poor folks race with Autolight AR2692 end style and small porcelain just > like the N-57G. Full size center wire, conventional strap, but 100% of the > center wire is exposed in an end view. Actually used by NASCAR and the local > circle track people, and stocked by Autozone and others. About $5.00 a box > of 4. They work fine. I raced them one weekend, no problems, but we were > getting the NGK plugs for free so I stuck with them. > > The NGKR6725-115 stamped on the body actually means that the heat range is > 11.5 not 115. $25.00 each. > 50% of the center wire exposed in an end view. Free for some Rotary engined > competitors. Retracted gap (the whole thing is inside the shell. Fine wire > center and fine wire ground strap. Ice cold. Long body so it is easy to > install and remove in the rotary. > > I grind off those eyebrow things above the plug holes so I can use any plug > I like. And any 5/8" plug just goes in so easy. Most heat ranges are > available in the 5/8" shells. > > Rotaries do not like high heat range plugs. The housings crack across the > leading plug hole. Over time a complete set of radial cracks form. > > In the picture, left to right is the Autolight AR2592, Champion N-82, NGK > R6725-115, and Champion > N-57G. > > Lynn E. Hanover > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > --0015175cdc6025081b046e29f206 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable The '93-'95 have the same spark plug specified as the 2nd gens, bot= h turbo and non - BUR9EQ/BUR7EQ.=A0 This is not really a surprise because, = even though the car is faster, the engine still spends 99% of the time putt= ering along at 2800 RPM making 30 HP.=A0 I would tend to agree that a colde= r plug is probably better for aircraft use because of the sustained high RP= M.

On Tue, Jul 7, 2009 at 8:43 PM, Lynn Hanover= <lehanover@gma= il.com> wrote:
In a message dated 7/7/2009 3:22:56 P.M. Pacific Daylight Time, bbradburry@bellsout= h.net writes:
Steve,
I hope Lynn chimes in here.=A0 He ha= s seen a lot of plugs under a lot of
conditions.=A0 They look pitted to me.=A0 There seems nothing wrong with yo= ur
conditions.=A0 The only thing on the list would be too lean.??
Som= eone is out there writing up a great response right now!=A0 :>)
Bill = B
That plug has been too hot.
=A0
Stock Mazda plugs are rather cold in heat range by way of the guards a= round the shell. The electrode runs a bit hotter than normal. Plug heat ran= ges are determined by how far down the shell the porcelain touches. The lon= ger the heat path, the hotter the plug.
=A0
Using car plugs in the aircraft application seems to be asking for tro= uble. In the car on the freeway you use 2,600 RPM and 1/2 throttle, maybe 2= 4 to 28 HP. Not much of=A0a challenge for a spark plug. But there is the
driver who will jump into his 95 twin turbo in LA and run out to=A0Las= Vegas at full tilt and expect to still have an engine when he gets there. A= nd usually he does. =A0So, if I was to use a street plug in an aircraft, I = would use the 93-95 twin turbo plug, whatever that is.
=A0
The aircraft application, less the 100LL fuel problem, is clearly a co= ld racing plug with a conventional gap or close to it.
=A0
Years ago when we started racing rotaries, Champion said to use the N-= 57G Fine wire center with gold paladium plating and a conventional ground s= trap. About 20% of the center wire is exposed in an end view.
=A0
The N-57G and similar are discontinued and the N-82 series replaced it= . The shell is thinner and the porcelain is wider. Same fine wire center, n= o gold anything. 20% of the wire exposed in an end view.
Both worked fine even with points and a Kettering coil.
=A0
Poor folks race with Autolight AR2692 end style and small porcelain ju= st like the N-57G. Full size center wire, conventional strap, but 100% of t= he center wire is exposed in an end view. Actually used by NASCAR and the l= ocal circle track people, and stocked by Autozone and others. About $5.00 a= box of 4. They work fine. I raced them one weekend, no problems, but we we= re getting the NGK plugs for free so I stuck with them.
=A0
The NGKR6725-115 stamped on the body actually means that the heat rang= e is 11.5 not 115. $25.00 each.
50% of the center wire exposed in an end view. Free for some Rotary en= gined competitors. Retracted gap (the whole thing is inside the shell. Fine= wire center and fine wire ground strap. Ice cold. Long body so it is easy = to install and remove in the rotary.
=A0
I grind off those eyebrow things above the plug holes so I can use any= plug I like. And any 5/8" plug just goes in so easy. Most heat ranges= are available in the 5/8" shells.
=A0
Rotaries do not like high heat range plugs. The housings crack across = the leading plug hole. Over time a complete set of radial cracks form.
=A0
In the picture, left to right is the Autolight AR2592, Champion N-82, = NGK R6725-115, and Champion
N-57G.=A0
=A0
Lynn E. Hanover
=A0

--
Homepage: =A0http:/= /www.flyrotary.com/
Archive and UnSub: =A0 http://mail.lancaironline.net:81/lists= /flyrotary/List.html


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