Mailing List flyrotary@lancaironline.net Message #53463
From: Steven W. Boese <SBoese@uwyo.edu>
Subject: RE: [FlyRotary] Re: GM Coil Comparison
Date: Mon, 3 Jan 2011 13:53:57 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

Kelly,

 

My spark plug life has been the same with the stock 13B coils and the D585 coils.  I have had SAG with the D585 coils also.  As I discussed at the Paducah fly in, SAG does not appear to be a spark plug misfire or failure to spark.  The effect on EGT and coolant temperatures is the opposite for SAG as opposed to no spark with either the trailing or leading plug.  I have seen evidence that SAG may be (similar to?) preignition caused by decreased thermal conductivity between the center electrode and the tip of the ceramic.  This decreased thermal conductivity results from corrosion between the ceramic and the center electrode and this corrosion is accelerated by the use of leaded fuel.  There is also some evidence for decreased thermal conductivity of the center electrode copper core as the spark plugs age.

 

Steve Boese

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer
Sent: Monday, January 03, 2011 1:17 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: GM Coil Comparison

 

Steve,

   Good to start the year off with an interesring and educational string !! Steve to shine

some light on Al's question about electrode erosion and possible "SAG" reduction what

has been your experience with plug life and have you had SAG with the D585 coil/igniters??

 

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Turbo

 

 


From: Al Gietzen <ALVentures@cox.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, January 3, 2011 1:38:42 PM
Subject: [FlyRotary] Re: GM Coil Comparison

Aside from the higher spark current from the D585s eroding the sparkplug electrodes more quickly; do we have evidence that it will, in fact, improve performance? Perhaps it is a cure for SAG.

 

BTW; my 6 D581 coils (Mounted atop my 20B) have been in use since my first engine start back in about 2001.  They have survived many hours of ground test runs where cowl temps exceeded 150F (at times I’m sure reached 190+ for short periods); and 200 fight hours with nary a single failure. In-cowl temps are typically about 150 during climb-out; and generally 120-140 during cruise.  

 

Perhaps it helps that they get plenty of air flow (during flight) being pretty much in blast from the rad exit.  I generally run the rad aux fan for awhile after shutdown; but I’d guess high temp is less of an issue when they are not operating.

 

Al

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy
Sent: Monday, January 03, 2011 8:13 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: GM Coil Comparison

 

I highly recommend the air cooled enclosure as Steve Boese (and I) use.  This is especially important on the D581 and the stock RX-8 Renesis coils.  The Renesis coils have a fairly high failure rate even on the car.   The D581 would only last a few hours at 150 F but I have about 250 hours on them with the airbox at 120F.

Don't forget to do the coil disable test to check for failed coils prior to every flight.

Tracy

On Mon, Jan 3, 2011 at 10:53 AM, Steven W. Boese <SBoese@uwyo.edu> wrote:

I have about 100 hours on D585 coils and have had no problems with them so far.  The temperature in their airblasted enclosure is usually less than 100 degrees in flight and has gotten up to 120 degrees during taxi.

 

Steve Boese

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy
Sent: Monday, January 03, 2011 8:41 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: GM Coil Comparison

 

I have a set of the D585 coils but have only evaluated them on the bench for compatibility with the EC2/3  (they are).

I do know that the previous version of the truck coils (D581) are not as reliable as the D580 (Corvette) coils.

Tracy

On Sun, Jan 2, 2011 at 2:16 PM, Kelly Troyer <keltro@att.net> wrote:

Happy New Year Group,

 

        A little info regarding the various GM ignition coils that many of us use on our

Rotary engines with Tracy's EC2 and EC3 boxes that I thought might be of interest

to those that have not seen it before.............Tracy would like your comments on the

the apparently big performance difference between the LS1 verses the LS2 Truck

coils and if an upgrade would be worth the $$ especially for those of us that have

or plan on Turbocharging in light of the higher combustion chamber pressures....... 

 

 

http://www.megamanual.com/seq/coils.htm#ls1

 

http://video.google.com/videoplay?docid=-6218245369765754251&hl=en


 

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Turbo

 

 

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