X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao06.cox.net ([68.230.241.33] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 931505 for flyrotary@lancaironline.net; Wed, 18 Jan 2006 11:56:06 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.33; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao06.cox.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20060118165217.JTNF20050.fed1rmmtao06.cox.net@BigAl> for ; Wed, 18 Jan 2006 11:52:17 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: LS1 Coil Failures Date: Wed, 18 Jan 2006 08:55:15 -0800 Message-ID: <000001c61c4f$f4e28d80$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C61C0C.E6BF4D80" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C61C0C.E6BF4D80 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Mark; =20 You raise a good point. The solid state components are 'potted' into = the housing; so vibration is not likely a factor, but internally generated = heat definitely is. Heat transfer out is likely rather poor. At these spark rates the internal components could be considerably hotter than the = 150-180F environment. =20 So higher re-drive ratio equals more need for coil cooling? =20 And do you really cruise down the highway at only 1500 rpm? =20 Al G =20 =20 Subject: [FlyRotary] Re: LS1 Coil Failures =20 Ed,=20 I was thinking about this a while back and was astounded at how many "firings" per second these coils are producing. Each rotor fires once/revolution of the eccentric shaft. Cruising along at 6000rpm, = that's 600 sparks/second/coil. My 5.3L Chevy truck (with LS1 coils), cruising = down the highway at 1500 rpm, each coil fires once every other revolution, or = 750 times/minute, or 12.5 times/second. So, we're really pushing these = coils to the limit. I find it amazing that they don't fail more often than this. = By the way, in 126,000 miles, I have yet to have a coil fail on my LS1. =20 =20 Mark S. =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Wednesday, January 18, 2006 9:09 AM To: Rotary motors in aircraft Subject: [FlyRotary] LS1 Coil Failures =20 Hummm, think I will hold off swapping my stock Mazda Coils for the LS1s sitting on my work bench until we have a better handle on the coil "problem". Have now flow for 300 + hours and over six years with the = stock coils with the only problem being the early failure of the leading = module because of a resistor opening in its base. =20 =20 The wattage of the resistor is apparently too low to carry the load of = the ignition continuously running at 6000+ rpm. Replaced the resistor with = a higher wattage one and no more problem. At least three people have had = this resistor fail using the stock coils - it may well be that the auto folks don't design for their coils to be run at high continuous rpms unlike = the MSD type ignitions for racing.=20 =20 I wonder what the automobile circle are experiencing with their LS1 = coils - anyone know? =20 =20 Ed A ----- Original Message -----=20 From: al p wick =20 To: Rotary motors in aircraft=20 Sent: Wednesday, January 18, 2006 9:57 AM Subject: [FlyRotary] Re: Coil & Alt cooling, Buly's input shaft =20 I'm wondering if 180f under hood is really the main cause for coil fail? Auto's shut off hot in desert, black steel hood, must see temps way = beyond anything we can throw at them. You can't get those puppies to fail regardless of environment. Perhaps there are one or two other = significant causes. I'd be real quick to abandon that manufacturer. =20 -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html =20 On Tue, 17 Jan 2006 22:39:15 -0500 "Tracy Crook" = writes: During my preflight tests this morning I found the third failed ignition coil in the last 150 hours so I finally got serious about dropping the = temps around my coils and alternator. =20 =20 I've been concerned about this since the under-cowl temps are as high as = 180 deg F (delta T through rads is 70 - 90 deg F). The attached photo shows = the solution (hopefully). The alternator plenum is made from a Tupperware container pirated from the kitchen with a skirt made from sheet silicone rubber. A 5/8" ID vinyl hose routes cool air from the oil cooler plenum = to it. ( 3/8" ID hose was tried first, not quite good enough) This was = tried prior to today's scrubbed flight and a temp probe shows that air inlet = temps to the alternator are only 3 - 5 degrees above ambient. Nice. =20 I had recently added a cooling plenum around the coils (also made of tupperware) and fed by a 3/8" ID hose but it was pretty leaky and only dropped temps about 10 - 15 degrees. After replacing the coil today I = built a better fitting plenum and fed it with 5/8" ID hose. This one is made = of space-age cardboard and I'll build a more permanent one from fiberglass = if it works OK. Will test tomorrow if wx allows. =20 Input shaft =20 Buly, got your input shaft today and checked it out. The thrust bearing rollers & races look a little stressed but the roller cage has been completely trashed. I do not think the .005" out of flatness on your bellhousing would explain this and the odd wear pattern on the plate. = The marks and discoloration (heat) on the bearing and shaft look as if there = is misalignment between the E-shaft and the gear drive. When you built = the plate & bellhousing adapter for the drive, how did you verify = concentricity? This is much harder to do than verifying the parallelism of the = bellhousing and plate but is absolutely vital. There is no question that the drive would have soon failed if you had continued to run it. Glad this = showed up before flight. =20 Tracy (Happy to hear that Dave L. is safe! Good flying. ) =20 -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ------=_NextPart_000_0001_01C61C0C.E6BF4D80 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Mark;

 

You raise a good point.  The solid state = components are ‘potted’ into the housing; so vibration is not likely a = factor, but internally generated heat definitely is.  Heat transfer out is = likely rather poor.  At these spark rates the internal components could be considerably hotter than the 150-180F environment.

 

So higher re-drive ratio equals more need for coil cooling?

 

And do you really cruise down the highway at only = 1500 rpm?

 

Al G

 

 

Subject: = [FlyRotary] Re: LS1 Coil Failures

 

Ed, =

I was thinking = about this a while back and was astounded at how many “firings” per = second these coils are producing.  Each rotor fires once/revolution of the eccentric shaft.  Cruising along at 6000rpm, that’s 600 = sparks/second/coil.  My 5.3L Chevy truck (with LS1 coils), cruising down the highway at 1500 = rpm, each coil fires once every other revolution, or 750 times/minute, or = 12.5 times/second.  So, we’re really pushing these coils to the limit.  I find it amazing that they don’t fail more often = than this.  By the way, in 126,000 miles, I have yet to have a coil fail = on my LS1. 

 

Mark = S.

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Wednesday, January = 18, 2006 9:09 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] LS1 = Coil Failures

 

Hummm, think I will hold off swapping my stock Mazda Coils for the LS1s sitting = on my work bench until we have a better handle on the coil = "problem".  Have now flow for 300 + hours and over six years with the stock coils = with the only problem being the early failure of the leading module because of a resistor opening in its base. 

 <= /font>

The wattage of the resistor is apparently too low to carry the load of the = ignition continuously running at 6000+ rpm.  Replaced the resistor with a = higher wattage one and no more problem.  At least three people have had = this resistor fail using the stock coils - it may well be that the auto folks = don't design for their coils to be run at high continuous rpms unlike the MSD = type ignitions for racing. 

 <= /font>

I wonder what the automobile circle are experiencing with their  LS1 = coils - anyone know?

 <= /font>

 <= /font>

Ed = A

----- Original Message -----

From: al p wick =

Sent: Wednesday, = January 18, 2006 9:57 AM

Subject: [FlyRotary] Re: Coil & Alt cooling, Buly's input = shaft

 <= /font>

I'm wondering if 180f under hood is really the main cause for coil fail? = Auto's shut off hot in desert, black steel hood, must see temps way beyond = anything we can throw at them. You can't get those puppies to fail regardless of environment. Perhaps there are one or two other significant causes. I'd = be real quick to abandon that manufacturer.

 <= /font>


-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock Subaru = 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru install, Risk assessment, Glass panel design = info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html

 <= /font>

On Tue, 17 Jan 2006 22:39:15 -0500 "Tracy Crook" <lors01@msn.com> = writes:

During my preflight tests this morning I found the third failed ignition = coil in the last 150 hours so I finally got serious about dropping the temps = around my coils and alternator.  

 <= /font>

I've been concerned about this since the under-cowl temps are as high as = 180 deg F (delta T through rads is 70 - 90 deg F).  The attached = photo shows the solution (hopefully).  The alternator plenum is made from = a Tupperware container pirated from the kitchen with a skirt made from = sheet silicone rubber.  A 5/8" ID vinyl hose routes cool air from the oil = cooler plenum to it.   ( 3/8" ID hose was tried first, not quite = good enough)  This was tried prior to today's scrubbed flight and a = temp probe shows that air inlet temps to the alternator are only 3 - 5 = degrees above ambient.  Nice.

 <= /font>

I had recently added a cooling plenum around the coils (also made of = tupperware) and fed by a 3/8" ID hose but it was pretty leaky and only = dropped temps about 10 - 15 degrees.  After replacing the coil today I = built a better fitting plenum and fed it with 5/8" ID hose.  This one = is made of space-age cardboard and I'll build a more permanent one from = fiberglass if it works OK.  Will test tomorrow if wx allows.

 <= /font>

Input shaft

 <= /font>

Buly, got your input shaft today and checked it out.  The thrust bearing = rollers & races look a little stressed but the roller cage has been = completely trashed.  I do not think the .005" out of flatness on your bellhousing would explain this and the odd wear pattern on the = plate.  The marks and discoloration (heat) on the bearing and shaft look as if there = is misalignment between the E-shaft  and the gear drive.  When = you built the plate & bellhousing adapter for the drive, how did you verify concentricity?  This is much harder to do than verifying the = parallelism of the bellhousing and plate but is absolutely vital.  There is no question that the drive would have soon failed if you had continued to = run it.   Glad this showed up before flight.

 <= /font>

Tracy  (Happy to hear that Dave L. is safe!  Good = flying. )

 <= /font>


-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock Subaru = 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru install, Risk assessment, Glass panel design = info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html

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