Can you lay out a simple schematic of the ADIS-4 firing two
 separate coils?  One for the front rotor and one for the rear
 rotor.  I was thinking the ADIS-4 #10 pin fired one coil and the
 front rotor and the #12 pin firing the other coil for the rear
 rotor, I am confused by the 12 volt power supply wire, through
 the #8 pin, going directly to the dual coils.  I am using a
 separate ADIS for the trailing plugs and all four coils that
 came with the Renesis engine so I won't have a wasted spark.

 --
 Karibian


 A 4 cyl EDIS won't work IMHO.
 It uses two waste spark coil packs to handle four spark plugs.
 Using a waste spark on the trailing plugs is not allowed
 so you are one coil short.

 An 8 cylinder EDIS system on the other hand uses four waste spark
 coil packs (four single coils) So you can use two stand alone coils
 for the the trailing plugs and one waste coil pack for the leading
 plugs I think but I would check it on a bench test set up before I
 put it on a rotary engine. It is also possible to use four stand
 alone coils with the 8 cylinder version which is what I recommend.

 Which EDIS system do you have? You will also have to find
 a Ford EDIS trigger wheel.
 http://www.megamanual.com/ms2/36-1.htm

 This pdf covers the whole thing for a piston engine.

 Paul Lamar

 Paul,  The EDIS 8 fires every 90 degrees of shaft rotation so only half
  the
 outputs are usable on an engine firing at 180 degree intervals.  The
  hall
 effect sensor is mounted about 52 degees befor the ignition point and if
 hooked up to the EEC 4 or 5 computer backs up the timing for advance.
 Without an input from an EEC 4 the coils fire 52 degrees of teeth on the
 trigger wheel from where the hall effect sensor is mounted.If I
 understand Karibian in his post he wants to use two EDIS 4  modules each
 firing two plugs at 180 degree intervals. If there are two hall effect
 sensors 180 degrees apart around the trigger wheel (18 teeth) each
  firing an EDIS module there are four independant sparks at 180
 degrees.  If the second Hall effect is retarded 1 tooth it will
 fire the trailing plugs 10 degrees different than the leading
 plugs.  Leaving the 18 tooth separation and firing leading and
 trailing plugs at the same rotation provides a completely
 redundant ignition system.  The EDIS is a waste spark system
 meaning that the spark energy goes to the cylinder with least
 pressure fires that plug goes thru the engine block and fires
 the second plug on the circuit back to the coil.  If only one
 plug is connected to the coil pack a path to complete the
 circuit brom the block back to the other terminal on the waste
 spark coil must be provided.Firing only one plug will
 dramatically increase dwell on the plug.  The EDIS and Hall
 effect sensor are really light, inexpensive even if new parts
 are used so using two of them doesn't seem to be a problem.  The
 parts are encapsulated in a plastic block so moisture,
 vibration, and low air density should not effect their
 reliability.  Using two 4 cylinder coil packs does add weight
 but until someone weighs two of them as compared to four single
 plug coils the difference in weight is unknown.  Using the 4
 tower coil packs that came with the EDIS would match the
 electrical resistance and inductance of the EDIS and coilpacks
 as Ford designed them and would be expected to be as reliable as
 the car ignition.  My piece of mind is worth a few ounce weight
 penalty using the waste spark coils.  The coil pack is actually
 only two coils molded together with a tower connection of both
 ends of each of the two coils for a total of four plug
 connections.  Two coilpacks is a total of four coils just like
 four individual coils just less mounting brackets to fabricate.



 george grimes

 I was afraid of something like that. Do you have a chart of
 a Ford V8 showing when each cylinder fires as a function of
 the crank angle? I have the firing order. Is the Ford a single
 plane crank or 90 degree crank? Must be a 90 degree crank if
 it fires every 90 degrees. Too bad I thought I was on to something.

 I guess you will need two 4 cylinder EDIS. With a little
 fooling around I think I can get one CAS to fire two
 units. Those are mag sensors and not Hall Effect.
 Hall effect require rotating magnets. Ford calls them
 "Variable Reluctance".

 I would not use the waste spark coil pack on the leading
 plugs with just one plug. I am not sure
 why. Have you tried it with out a spark plug load?
 I dimly remember from way in the past that could be
 a no no. Perhaps it arcs over inside the tower.


 Paul Lamar

   Paul,  It fires an EDIS 8 every 90 degrees just like when
 it had a distributor cap.  It fires one coil pack every 9 teeth
 on a 36tooth wheel.  Using the waste spark coils fires the 4
 cylinders on the second revolution using the same four outputs.
 Using a 27 tooth wheel with an EDIS 8 there would be three
 outputs 120 degrees apart (still counting 9teeth) and the
 missing tooth would reset the count not firing the
 fourth output'.  I haven't tested this three rotor idea but IMHO
 that is how it works based on two weeks of Internet research.
 Personally for the return circuit back to the waste spark coilI
 suspect a resistor would be required in series with the
 plug lead.  I am intending to just screw some extra spark plugs
 into a block of aluminum bolted to the block which won't fire
 anything just provide the electrical load.  For the four rotor
 there is a small pad on the connector bell housing between the
 engine sections thick enough to screw the plugs into which was
 necessitated to be able to remove the pattern from the
 castings and You are right they are actually variable reluctance
 coils not Hall effect.  I am going with two of them so that I can
 fire the plugs separated by a few degrees of E-shaft rotation and
 to make each half of the ignition completely independent.  This
 is also a multi-spark ignition at the lower RPM of the car engine
 but resorts to single spark at high RPM with an upper continuous
 RPM of 8000 RPM With no moving parts and the reliability and
 price of well developed mass production parts I just don't see
 any downside to this stand alone ignition.  Ford liked it enough
 to build 12 million of them before incorporating it into the
 engine computer.

   george grimes

   Upload a schematic for Hurant.

   Paul Lamar

   George...

   I am not certain that the current path you described above is
 correct. I
   have always read that the wasted spark was really not a full spark
 due to
   the much lower pressure and conductivity of the combustion atmosphere
   compared to the cylinder that is loaded with fuel and air. The
 current is
   simply looking for the least resistant path, and the charged
 cylinder is
  it.
   Therefor, of the two possible outlets of each coil, the one with the
  lowest
   resistance at the point of arc, releases the load.

   Correct me if I am wrong

   Ed Carver

   Here is the way I think it works.

   Air is an insulator. Higher pressure better insulator.
   Higher resistance. High altitude magneto's must be
   pressurized.

   Power = voltage times current. The waste spark is looking
   at a comparatively low pressure low resistance chamber. Almost a short.
   There is no voltage across a short. So no power is dissipated but
   the spark jumps easily.

   So the compressed mixture gets most of the spark POWER.

   One might try grounding the un used spark tower.

   Paul Lamar Leesburg VA

  If the coils could handle it the ford edis 4cyl would be ideal for the
  2 rotor. Each coil fires It's two plugs every 360 degrees. And the
  coils fire 180 degrees apart.
  The edis coils can't handle two sparks under pressure.
  The edis coils do not have igniters built in. LS1 coils do. So you
  could remove the edis coil and fire four ls1 coils. It would take a
  big resistor between the edis module and the coils. LS1 coils fire on
  a 5v signal.
  Blake
  --
  Blake C. Lewis


 Have been following this thread for a while. However, with having only
 one
 rotor to fire in the single rotor, I had not much to contribute. There
 is an
 exception with something I ran into. Using a coil with a build in igniter
 like an LS1 or RX8 coil the following need to be considered. These
 coils are
 unsuitable for using with a direct CAS trigger. The 5V signal need to be
 appr. 2ms long, and the spark occures at the end of this pulse,
 resulting in
 a constant 2ms delay of the timing. This can only be accounted for
 with an
 ECU.
 I am using on the single rotor a Street Fire CDI,  firing a single waste
 spark coil from an older GM.
 FWIW.

 Richard Sohn
 N2071U
  --
 Thanks Richard. That answered the questions I had on those type
 of inductive ignition systems. I suspected as much. I won't
 waste any further effort with them. I suspect this may be the
 cause of some of Marks S ignition problems. However any CD
 system can be  fired when needed as long as there is enough
 time to charge the cap.

 The EDIS on the other hand has the ECU built in.
 And that is why it needs to be set 10 degrees ahead.
 It may not work at 7500 RPM.

 If one is thinking of using it one better test it with
 the Ford trigger wheel mounted on a high RPM electric
 motor.

 ------------------------------------------------------

 This deserves a better explanation as it is fundamental
 to understanding inductive ignition. The 2 milliseconds
 Richard mentioned above is the time it takes for the
 current flowing through the coil to increase to
 its maximum value once the bottom end of the primary
 winding is shorted to ground by the transistor.
 If this time is too long the coil may over heat
 and die. Early Tracy's systems had this problem
 as I recall until Tracy decreased the time.

 It is difficult if not impossible to do this
 by simple sensors looking at the trigger wheel.
 The 2 ms is a fixed time period while the time
 it takes for a given tooth to pass a sensor varies
 with the RPM. As Richard stated some sort of
 device must make these timing calculations.

 Here is a schematic for the Ford EDIS. From
 this you can see it is not a cap discharge
 type ignition and merely an inductive system
 where the 2 ms rule applies.

 The micro controller in the stand alone unit
 does the timing calculations. The 10 degree
 additional advance gives the micro controller time to
 calculate the 2 ms coil charge period and then
 fire the plugs.

 It fires the plugs by rapidly interrupting the coil
 current in the primary of the coil transformer
 inducing a very high voltage into the secondary.

 It takes about 7.5 milliseconds to rotate at
 8000 RPM and two plug firings periods are required
 for the rotary. That leaves 3.75 milliseconds to
 calculate the 2 ms coil charge time period and start the
 current flowing in the coil. A lot now depends
 on the speed of the micro-controller used
 so the Ford EDIS system must be tested at
 that RPM to be sure it will work. We don't know
 what type and speed processor the Ford EDIS
 system uses.


 All this pretty much rules out the stand alone coil
 on plugs systems. That leaves the EDIS or a CD system
 of some sort.

 As far as firing both plugs at the same time with
 a 4 cylinder Ford EDIS,  one plug on each end of the
 waste spark coil, is a simple solution for the rotary
 but the energy in the spark may be much lower.

 BTW the CD system may solve the plug sag/life problem.

 Paul Lamar


The graph for Input Power Consumed appears to be for an constant-dwell
system such as a distributor-based breaker-point system would use.  In
such a system the points stay closed longer at low rpm and thus the DC
resistance of the coil and ballast resistor are the primary determinant
of current flow. At higher rpm the inductive component increases the
apparent resistance so the current goes down.
Inductive solid-state with a 2 ms trigger would be parallel to the
capacitor discharge system, as every spark event has equal energy
consumed, just as the CD system.
The 2004 Chevy Tahoe uses LS-type coils and I have measured the trigger
pulses on the vehicle at 5ms for all rpm. I do not have access to a
Corvette with the LS-1 coils to check what GM uses in that installation
but in playing with a set of LS-1 coils I have determined that the
current flow into the coil indicates about 95% saturation at 5ms. I
cannot detect any difference between the LS-1 and the Tahoe coils in my
test setup.  Useful spark can be achieved with pulses of less than 1ms,
but the energy is much lower than that achieved with longer duration.

Victor Roberts

Another data point. Thanks Victor. 5ms is too long for a for a waste
spark system on the rotary trailing plugs as we must interrupt
the coil every 4 ms at 7500 RPM. That will work however for one
coil per plug computer controlled such as Tracy's system or Ford EDIS.

In theory the CD cap can recharge to 86.5% in as little
as .6 usec given an upper FET on resistance of .3 ohms. Lower
FET on resistance  is available. It takes the e-shaft 222 usec to
rotate 10 degrees at 7500 RPM. That gives me at least 100 usec to recharge
the cap if I wanted to use just one cap, one totem pole circuit and
one coil per spark plug. That is two sparks every 10 degrees.

If I wanted to go to the waste spark coil for the trailing
plugs and one totem pole I would have 4 mses or 4000 usec
so I could still fire four times using 888 usec. That
still gives me over a millisecond to recharge the caps.

Here are some scope pictures for the Aussie system using
an IRF822 FET with a 3 ohm on resistance.

Also the number of sparks for a 4 cyl which I think
we can do better.

Paul Lamar