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/
>



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