> Paul,
> I recently had a chance to snag a complete LS-7 coil
> pack set with the
> D-585 coils.  Here are a couple of  photos of how it
> would fit if
> mounted near the 13b.  There is substantial benefit
> gained by leaving
> the coil pack intact.  The wiring harness is
> vibration proof and
> requires wiring to only one connector.   The spark
> plug wires have the
> impedance matching spring and EMI shield on them.
> The weight including
> the wires is approximately 5 lb.  Here are the
> numbers on the individual
> parts:
>
> Wire harness:  6071
>
> Mounting bracket for all four coils:  4201504
>
> Coil:  L34A29 over 1057 two coils,  and   R34A29
> over 1057 other two
> coils  (The four coils are identical in appearance.
> One coil has a
> sticker marked 4A29),      the steel mounting clamp
> around each coil
> 19005218
>
> Plug wire:  coil boot Delphi 403,  wire  AC Delco
> 9079,  no marking on
> spark plug end
>
> harness plug coil end:  Delphi PBT (4 conductors:
> Bk, Br, Pnk to all
> coils, then Rd, Bl, Gn, Vio to respective coils)
>
> harness jack main connector:  no id marks  (7
> conductors)
>
> inventory tag?, tape wrapped on harness:  15423372
>
> weight complete:  approx. 5 lb
>
>
> Aubrey
>
> The big question is are they going to live being
> pulsed
> twice as often as on the V8? We need to set up a
> test rig
> and measure the temperature rise on the coil as a
> function
> of pulse rate. The rotor fires once per rev while
> a cylinder fires once every two revs.
> --
> Paul Lamar ...No rotor no motor.
>

paul,

i would like to know why gm decided to use single
coils per cylinder, was it performance reasons or just
for marketing? on their 4 and 6 cylinder engines they
use waste spark coils, one per every two cylinder, so
they do spark every revolution. and of course the old
v8 distributer engines used a single coil sparking 4
times per revolution.

as you've written before the big difference between
automotive and aircraft is that the automotive engines
are designed to only run at low power low rpm for
extended times versus the high power high rpm use in
aircraft. i suspect, as was mentioned before, that
putting the coils in a cool air stream will take care of
any potential heating problems. in auto use these
coils sit under hood in a very hot area.

gary

The new one plug per cylinder coils are a lot smaller than the
old big and heavy dist coil enclosed in a metal container
containing oil.

Those old engines had red lines of 4500 RPM.

Paul Lamar

I think the main reason they did away with the old one
coil system and went to one small coil per plug is it
did away with the distributor. It is now up to the computer
to fire the coil when needed. Probably cheaper as the distributor
was expensive to make.

Also the one coil system works fundamentally different than the
one coil per plug systems. In the old days if you turned
on the ignition switch and the points happened to be closed
a large current would flow through the coil on a continuous
basis. I was told as a young boy not to do that. The coil would
get real hot. A large power resistor called a ballast resistor was
used to limit the current.

When the points opened the coil would fire the plug.
The faster the engine ran the less average time the current
had to flow through the coil so the coil actually ran cooler.
It was called dwell time. At high RPM one could run out of
dwell time and the secondary plug voltage would start to
drop off.

By contrast the computer now controls the dwell time at
about a fixed 3 ms. Just enough time to fully charge the coil
with current (let the current build up to a maximum controlled
by the DC resistance of the coil) and the plug fires when the
computer turns the coil off at the end of the 3 ms. The magnetic
field breaks down rapidly causing the secondary winding to
generate a spark. Of course since there is one coil per plug
there is more time at high RPM for dwell time so the one coil
per plug worked better at high RPM.

Unfortunately the one coil per plug are designed for four cycle
piston engines that fire half as often as rotaries.

Perry Mick and I are working on a revolutionary ignition system
if he can come up with a high power high voltage power supply.

Paul Lamar ...No rotor no motor.

-------------------------------------------------------------------
Have you considered something like the EHT circuit/s from a CRT (TV)
or a large computer monitor 19"to 21" these output over 25KV to 35KV
maybe something along those lines might suit what you want to do.
There is certainly enough voltage and will more jump the distance.

Regards David Gaze

Yes I always thought they might make good ignition coils.