The lost coil count is now up to 3.  The ones that went bad were the Delco # D581 LS1 Truck coils.  I have not had any problems with them (still using 3 of them) since installing a cooling plenum over the coils fed by a blast tube but I no longer carry or recommend them. 

 

 The D580 version for the LS1 Corvette engine has no history of failure that I know of and that is what I now carry and recommend. 

 

GM came out with a "new style" coil for the truck engine (Delco # D585) that has a heat sink on the igniter side of the coil.  They don't say it is a fix for heat related failures of the D581 but there is little doubt in my mind that it is.

 

Tracy

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

From: Ed Anderson

To: Rotary motors in aircraft

Sent: Tuesday, May 23, 2006 1:36 PM

Subject: [FlyRotary] Re: Another case of heat-soaked coils?

Tracy, lost two LS1 coils believed due to over heating.  He now has air flow
to his 4 LS` coils (also sitting on top of the engine).  I suspect the Mazda
coils may take more heat than the LS1 coils, I have not lost one to heat
(yet)  - but that is just speculation on my part.

Ed
----- Original Message -----
From: <cardmarc@charter.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, May 23, 2006 1:30 PM
Subject: [FlyRotary] Re: Another case of heat-soaked coils?


> Heat soak of the coils is hard to believe. In the 3rd gen turbo cars the
> coils sit on top of the engine between the engine and the intake manifold,
> and they get mighty hot and hardly ever stop working, in traffic at +100F,
> with ac on, stop and go.....?
> Marc
>
> ---- Kelly Troyer <keltro@att.net> wrote:
>> And the people said "Amen" !!
>> --
>> Kelly Troyer
>> Dyke Delta/13B/RD1C/EC2
>>
>>
>>
>>
>>
>>
>> -------------- Original message from "Tracy Crook"
>> <lors01@msn.com>: --------------
>>
>>
>> Right-O on the difficulty of long distance diagnosis.
>>
>> John did tell me that the threshold of 'splutter' was around 38" Hg MAP.
>> Since the engine quickly went down hill even at lower throttle settings
>> and he thought it was only running on one rotor at the end of testing,  I
>> suspect there are a lot of clues to what is wrong other than the
>> 'splutter' at 38".   We just don't know what they are.  The coils being
>> bad is a long shot since it would mean that two of them died at once, not
>> likely but possible.
>>
>> Sermon follows:
>>
>> Guys,  Learn to be very sensitive to your engine.   Know every nuance of
>> its character.  If you don't know what the air drifting out of the inlets
>> after shutdown smells like,  you aren't paying enough attention.
>>
>> Tracy
>> ----- Original Message -----
>> From: Ed Anderson
>> To: Rotary motors in aircraft
>> Sent: Tuesday, May 23, 2006 7:45 AM
>> Subject: [FlyRotary] Re: Another case of heat-soaked coils?
>>
>>
>> John, Not being there makes it hard to make an assessment.  Anytime I
>> have
>> had an engine spitting and popping it either mean the air/fuel mixture
>> was
>> too lean or I had a ignition problem (mainly timing).  I have no
>> experience
>> with any coils other than the stock Mazda but additional cooling
>> certainly
>> could not hurt.  It really sounds like to me your engine is increasing
>> rpm
>> until its getting into a region where the air/fuel mixture may be too
>> lean.
>> Normally a too lean engine will pop and spit but not certain if your
>> sputter
>> is same as my sputter {:>).  Also you did not mention what boost levels
>> you
>> were running when this was happening.
>>
>> Ed
>>
>>
>>
>> Any time my engine acts abnormal, its grounded until I figure out the
>> problem
>> ----- Original Message -----
>> From: "John Slade" <sladerj@bellsouth.net>
>> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
>> Sent: Monday, May 22, 2006 9:56 PM
>> Subject: [FlyRotary] Another case of heat-soaked coils?
>>
>>
>> > Yesterday I took a friend for a ride and the engine purred sweetly for
>> > the
>> > entire trip. Looking back, the only thing different was that there
>> > didn't
>> > seem to be an rpm drop when I disabled leading or trailing coils during
>> > the runup.
>> >
>> > Today all was normal during runup (except perhaps the coil disable
>> > causing
>> > no rpm drop) and full power got me 5300 before I couldn't hold it any
>> > more
>> > on the brakes. Take-off and climb were normal. On the downwind I was
>> > showing 5800 rpm so I decide to coursen the prop. When I did I felt a
>> > splutter. I reduced throttle and the engine ran normally. I increased
>> > throttle. More splutter. I reduced throttle and it ran normally at
>> > 4600.
>> > Any more throttle and all I got was reduced power & popping and
>> > spitting.
>> > I circled the field trying mixture adjustments, checking fuel pressure
>> > on
>> > both pumps, coil & injector defeat and swapping to B computer. Nothing
>> > seemed to make any difference, so I landed.
>> >
>> > The only change since the previous flight was that I'd replaced the
>> > plugs
>> > with a clean set - not new - just clean. Suspecting a bad plug I let
>> > the
>> > engine cool down a bit, then installed new ones. Later in the day the
>> > engine ran fine during taxi and again reached 5300 on runup.
>> > Acceleration
>> > seemed normal then, halfway through the takeoff roll, I felt a
>> > splutter,
>> > so I aborted and rolled off the runway.
>> >
>> > When I added power to taxi clear of the runway the spitting got much
>> > worse. So bad, in fact that it seemed to be running on one rotor and
>> > there
>> > was insufficient thrust to move the plane forward. I tried adjusting
>> > mixture and defeating injectors & coils again and the engine eventually
>> > stopped. I was able to restart, but had the same symptoms. The rpm was
>> > fairly steady at 1100 or so, but this was the max rpm I could get. The
>> > EM2
>> > was flip flopping rpm readings 2300...400...2100..800...every couple of
>> > seconds.
>> >
>> > I called Tracy from right there on the taxiway. As always - he took the
>> > call and listened to my unscientific whining. Thank you Tracy :)
>> > Anyway,
>> > his best thought was that it sounded like it might be a coil heat-soak
>> > problem. It definitely seems heat related, and my cowl has been running
>> > a
>> > bit hotter since I installed the new T04 turbo.
>> >
>> > I pushed (yes pushed) the plane back to the hangar, then tried turning
>> > the
>> > prop to feel all six compression strokes. To my untrained arm muscles
>> > the
>> > compressions all felt the same. I ordered 4 new coils and will report
>> > if
>> > this corrects the problem. Whether it does or not, I see a separate air
>> > duct for the coils in my future. The blow tube I installed may not be
>> > providing enough cooling. I once tried installing a temp sensor at the
>> > coils, but this sent other EM2 temp readings haywire - induced current
>> > from the ignition? - so unfortunately I don't have temp readings on the
>> > coils.
>> >
>> > Anyone have additional thoughts on this?
>> >
>> > Sincerely,
>> > Frustrated in Florida (I could add another F at the beginning to help
>> > with
>> > the .ing alliteration, but I won't)
>> >
>> >
>> >
>> >
>> > --
>> > Homepage:  http://www.flyrotary.com/
>> > Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>> >
>>
>>
>>
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>



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