1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

doing the direct fire

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Old Mar 26, 2004 | 12:58 AM
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doing the direct fire

ok I am getting the MSD 6a, 2 blaster 2 coils, and 1 accel coil for the trailing.... I read the how to and I am still a little confused... it says I dont need the DIZZY at all but does that mean I just dont plug into it except for the signal wire or can I take some of it off for a cleaner look... I have never done ignition on a car before really so I dont know... I know I cant take it all out because of timing... does anybody have any pics of there direct fire system and what everything looks like?
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Old Mar 26, 2004 | 01:01 AM
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not sure if this is what you read, but it's got pics. =D

http://www.mazspeed.com/msd.htm
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Old Mar 26, 2004 | 02:12 AM
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I'm still not convinced that splitting the output of the MSD is a good idea. People keep doing it though.
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Old Mar 26, 2004 | 10:57 AM
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https://www.rx7club.com/showthread.p...hreadid=287203

Check it out, it is Paul Yaws Direct Fire Ignition conversion.
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Old Mar 26, 2004 | 12:35 PM
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hey thanks guys I read yaws but that one on mazspeed helped out more since it had pics...
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Old Mar 29, 2004 | 07:20 AM
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Jeff20B-
I really don't understand what your objection to the MSD 6A is (other than cost, which is a valid concern.) Don't get me wrong - I like your DLDFIS setup, and will probably try it, but remember that the MSD is just *triggering* the coils to fire. The "power" of the ignition depens on the coils, not so much the trigger, yes? I mean, you can trigger the things by touching a wire to ground and then removing it. It's the collapsing field in the coil that generates the spark.
Now, having said that, I'm not convinced that the MSD's method of firing, the Multiple Spark Discharge that gives it its name is of any benefit to rotaries. It's supposed to fire over 20 degrees of crank rotation, but that's on piston engines. Not sure how it actully works out on our weird engines. I do know from other's experience that the 6AL's rev limiter is next to useless on our cars, since the thing will just keep revving on the trailing ignition.

On a slightly different tack, will a second-gen leading coil pack with integrated ignitor fire off of the magnetic trigger in an FB dizzy? I think someone tried this on the SA22C email list, but I forget the results. I know that it will fire off of the stock FB ignitor with the built-in ignitor removed...

You know, now that I think about it, I'm not so sure that your DLDFIS is necessary. I think that one ignitor might do the job. Remember, this is wasted spark - one of the coils is firing against exhaust, so it's "easy" to fire. Should't require much in the way of trigger signal to light it off. Hmmmm... Need to get an FC leading coil...
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Old Mar 29, 2004 | 11:33 AM
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First you misunderstood what I was saying. The CD output of the MSD is a low amp/high volt jolt that is great for firing a single coil. When people start hooking up two coils in parallel, it cuts the already low amps in half. This produces a weaker spark on both coils. My solution is to use an FC leading coil so there is only one primary for the MSD to 'jolt', thus the amperage will be up to normal.

The MSD's mutlisparks go down to one spark at who knows what RPM. Seriously, there is no way to know. There is no info in the instruction booklet other than it fires multiple sparks over 20º of crankshaft rotation (no mention of the amount of cylinders etc). Whatever that translates to for rotaries is anybody's guess.

Rotaries need a long duration spark. The MSD provides a short duration spark at probably anything above idle.

If you try to fire an FC coil with an FB ignitor, the ignitor will burn out. You need the ballast resistor that usually comes with the FC coil. Inittab has done this and it worked If memory serves.

One ignitor hooked to two coils in series is called SLIDFIS (Single Leading Ignitor etc). It didn't work in parallel due to too little resistance (too much load).

You're kinda like I was back in '99 just starting to experiment with rotary ignition stuff. Keep on learning. It's fun.
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Old Mar 29, 2004 | 11:36 AM
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double

Last edited by Jeff20B; Mar 29, 2004 at 11:42 AM.
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Old Mar 29, 2004 | 11:37 AM
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tripple

Last edited by Jeff20B; Mar 29, 2004 at 11:42 AM.
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Old Mar 29, 2004 | 03:03 PM
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Originally posted by Jeff20B
First you misunderstood what I was saying. The CD output of the MSD is a low amp/high volt jolt that is great for firing a single coil. When people start hooking up two coils in parallel, it cuts the already low amps in half. This produces a weaker spark on both coils. My solution is to use an FC leading coil so there is only one primary for the MSD to 'jolt', thus the amperage will be up to normal.

The MSD's mutlisparks go down to one spark at who knows what RPM. Seriously, there is no way to know. There is no info in the instruction booklet other than it fires multiple sparks over 20º of crankshaft rotation (no mention of the amount of cylinders etc). Whatever that translates to for rotaries is anybody's guess.

Rotaries need a long duration spark. The MSD provides a short duration spark at probably anything above idle.

If you try to fire an FC coil with an FB ignitor, the ignitor will burn out. You need the ballast resistor that usually comes with the FC coil. Inittab has done this and it worked If memory serves.

One ignitor hooked to two coils in series is called SLIDFIS (Single Leading Ignitor etc). It didn't work in parallel due to too little resistance (too much load).

You're kinda like I was back in '99 just starting to experiment with rotary ignition stuff. Keep on learning. It's fun.
The 2nd gen coil works perfectly when you open up the back, wire in the resistor that's already in there with the wire from the stock coil. I did a write up on it- it's on the FAQ sticky. It works quite well, and would be a great candidate for MSD if you decided to do it. The 2nd gen ignitor is useless, btw... throw it out.
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Old Mar 29, 2004 | 05:07 PM
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How about if you hook the magnetic trigger fo the dizzy to the FC ignitor in the coil? Plug it in like you would an MSD?

And I still think that the MSD puts out way more than enough to trigger multiple coils. It's only something like 50mJ to trigger a coil. Here's part of the thread from the MegaSquirt Yahoo group discussion:
Exactly. But the capacity in this case is generally 100-150mJ. Which is quite some belt. Given that in most cases you only need 50mJ to get a good fat spark I can't see a problem. Certainly the rotary boys have been firing 2 big coils in parallel without problems for many years.

Certainly an area for research though. I'm planning to get some of the new GSXR COP coils and have a play some time.
Bill



========================================
Message date : Mar 29 2004, 03:07 AM
From : "clare"
To : megasquirt@yahoogroups.com
Copy to :
Subject : [megasquirt] Re: Coil on plug ignition, doable?
bill SHURVINTON writes:

Clare,

curiousity piqued. Why do you think this is so?

Bill

Do you understand how a CDI works, compared to a standard Kettering
ignition?
A capacitor is charged , then fired into the coil, which is a "pulse
transformer" The capacitor, unlike the battery of the kettering system, has
a very finite capcity
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Old Mar 29, 2004 | 05:11 PM
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why dont you guys just have 4 msd 6as and 4 coils to run each sprakplug
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Old Mar 29, 2004 | 06:57 PM
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Originally posted by riceburner1r2001
why dont you guys just have 4 msd 6as and 4 coils to run each sprakplug
4 MSD's = 640.00+4 coils= $48 for a grand total of $688.00.
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Old Mar 29, 2004 | 11:24 PM
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PaulAber: you said it ! ! !
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Old Mar 29, 2004 | 11:24 PM
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PaulAber: you said it ! ! !
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Old Mar 30, 2004 | 01:14 PM
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I just realised I had another Diamond coil last night. I found it in a box with a rat's nest and other odds -n- ends.
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