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Bill,
Because this plug has been used by several on this list and its use has been a topic
of discussion in the past.................."And" because one of the most knowledgeable
members of our little group Lynn Hanover has personally seen it used............But
you are correct that one has to be careful what plugs you put in a 13B to make
sure that nothing projects into the rotor chamber on the leading plugs and that the
plug tip is not too long and makes contact with the steel rotor housing liner when
used for the trailing plug (Small plug opening).............Jump in here Lynn !!............
A noted Arizonia rotary engine builder tested this plug some years ago and his
most notable comment was that it did not live as long as some of the others he
had tested.............But they are relatively cheap and if they will last as long as
any other plug before encountering "SAG" then their use might be easier on the
pocketbook.............I plan on their use for breakin and tuning and flight if no
problems with them are encountered............FWIW
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from "Bill Bradburry" <bbradburry@bellsouth.net>: --------------
Kelly.
I have always been afraid to change something like plugs that I don’t know anything about. I read somewhere that the plug could extend into the chamber and be hit by the apex seal. How would you know that a plug would fit if it is not listed?? (other than Lynn said it would :>) )
Bill B
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer
Sent: Wednesday, July 08, 2009 7:45 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] SAG- Spark plugs 2592 or 2692?
You are correct................You have to look up the AR2592 plugs by part number............This plug
is actually used in some early Chevrolet and Chrysler Big block engines for racing..........
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from "Bill Bradburry" <bbradburry@bellsouth.net>: --------------
Kelly,
I don’t see a call out for the rotary engine in the Autolite info…???
Bill B
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer
Sent: Wednesday, July 08, 2009 3:27 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] SAG- Spark plugs 2592 or 2692?
I believe the mystery is solved...............Apparently "AR2692" is a typo error
and "AR2592" is correct..............Check out the link below............Full of info.....
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from "Kelly Troyer" <keltro@att.net>: --------------
I have never found a trace of a "AR2692"............Lynn which is correct ??...................
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from Jeff Whaley <jwhaley@datacast.com>: --------------
Lynn’s email referenced 2 part numbers … Poor folks race with Autolight AR2692 and … In the picture, left to right is the Autolight AR2592.
So which number is it correct? 2592 or 2692?
Jeff
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer
Sent: Wednesday, July 08, 2009 2:35 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] SAG- Spark plugs
I checked my local "Auto Zone" and they claimed to be unable to get the "AutoLite"
AR2592 sparkplug...............Checked "Rock Auto" (Link below) and they have them in
packs of 4 for $2.69 (each plug)...........Ordered 8 of them for $21.52 + $5.47 shipping
but "AutoLite" has a rebate offer of $0.50 per plug for up to 16 plugs until Nov. 30,2009
for copper core plugs (rebate link below).............To find the sparkplug do a part number
search (AR2592) , Add the manufacturer (AutoLite) , Then use "all" for the part group
because if you use "Ignition" and "Sparkplug" for part type it will say "No part found"....
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from Lynn Hanover <lehanover@gmail.com>: --------------
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
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