rotarydankus again

okay, two 75 corvette spec hei modules [they have longer dwell) trash the mazda igniters, on top mazda ign, theres two wires one keyed hot , other way shinnier goes to -coil . on gm hei mod one end has an b on one term, and a c on the other, they get pluged into the original mazda igniter wires,the other two terminals at the other end are marked L and H , they get jumpered to the stock pickup terms, get it ? then get you two saturn or gm DIS coils, I used saturn ones cause i have 1/2 doz of them laying around, i wired them up to the factory coil harnesses and plugged the leading wires to the 1 and trialing to the other, had to change boots cause gm used pedistal coil terms, viola fired rite up no putter at all , and them suckers will throw three inches of spark so be careful, will make diagram meanwhile heres pics

hett2jzgte

i would be very grateful for a closer shot

alien_rx7

No putter, but how does the car run overall on the street now?

rotarydankus again

i cant tell that theres any difference but it starts fast, it runs considerably smoother, warming up this morn only puttered 4 or 5 times in 5 minutes! heres a better set of pics

rotarydankus again

heres another angle

rotarydankus again

i got rid of the old roter and cap and the coils, double checked timing today, rite on. only need a connecter that will fit the factory pickup, heres another view

Jeff20B

iTrader: (13)

If both your leading plugs fire at the same time, how did you seperate the trailing plugs?

rotarydankus again

didnt used another coil for trails , it acts the sam as the leadings, only 20 degrees later, the gm system is waste fire the cylinder not under compressin fires anyway it just doesnt matter , if you had two picckup coils u could do a 4 cyl, 3 a v6 4 a v8 5 a v ten get it ? thanks trev

Jeff20B

iTrader: (13)

So you're saying that you're not running simultaneous firing on your leading plugs then?

Your engine would probably have more power with less than 20º split between L and T. Also, I'd like to ask you if both your leading plugs fire at the same time.

If your trailing are running just like your leading, only 20º later, then you've got single leading sparks, and single trailing sparks per each rotor face. Fair enough. That's how a stock FB runs.

rotarydankus again

yes jeff u r correct they both fire simultaneosly, you just like the fc , only they used three coils, the thing about saturn coils was size they are easier pakaged, and the gm module is already up for the task , u were saying more /better performance if i narrow up the gap, by how many degrees ? and do you draw the leading towards the trailing or vise versa? on the scope kv readings hit 40k+ nice spark lines and lots of dwell, i get a stutter on rough roads that i think is poor vibration resistance at the pickup coil plugs as i used just solder on terminals, no connector body , will fix this asap , thanks for info , jeff, was hoping to get on dyno today but seeings, how theres only 24 hrs in day instead of 36 i didnt have time

Jeff20B

iTrader: (13)

The only thing you've got to watch out for are firing the trailing together. That would be bad for the engine. It's ok to fire both leading together, like what your is running doing now.

Leave the leading where it is and move the trailing closer. Bring it down to 15º and see if there is a difference. You can experiment from there. Try 10º and 8º after you've gotten familier with how to adjust trailing timing. If you've still got the vacuum pot on your dizzy, look for the one with the two screws on top. Loosen them and the trailing pickup can be rotated slightly inside the dizzy housing. Tighten the screws when you're done.

rotarydankus again

jeff why would firing both trails together, its the same event as the leading only later right ? what am i missing? the whole point was to get rid of the cap and roter cause they look dorkey with three empty holes, now youve got me worried its on there now,

Jeff20B

iTrader: (13)

The reason why it's bad to fire both trailing plugs together is because one will always ignite the incoming mixture BEFORE it gets down into the correct area of the engine.

You may have saved your engine from disaster with your trailing timing so far behind leading. With trailing 20º after leading, it allows the rotors to rotate further before igniting.

Or maybe I'm not thinking very well right now since it's late here. others are welcome to answer your questions with regard to rotor timing, advance/retard, firing trailing at the same time (and why it's a bad idea), etc.

rotarydankus again

i took a closer look at the fb cap and roter , they split the leadings and the trails simul fire , so i looked at the fc coils , lo and behold they fire the leads together, and the trails are on separate coils but share igniters, which leads me to believe that they simul fire too, ttso i should be alright , rite?

hornbm

Mabey its just me, but I cant understand a single word your saying dude. Incomplete sentences dont really bother me, I use them all the time. However incomplete words are just insane! Are we to lazy to finis typin ou word?

Jeff20B

iTrader: (13)

Why would they simul-fire from two seprate coils?

You're on the right track, but not quite there yet.

The FC fires both leading plugs together, like you said. The FB fires them selerately, like you said. So far, you are correct. Both the FB and FC fire their trailings 180º apart. The FC does it with direct fire out of two seprate coils, while the FB does it with one coil out of a cap.

You're almost there. I just wanted to try to make it a little more clear.

honegod

I am new to all this, and am confused.

the FB dizzy I have has a cap and rotor.
the FC dizzy I have has NO cap and rotor.


the FB dizzy has one reluctor {cam} for two pickups.
the FC dizzy has two seperate reluctors {cams} one for each pickup.

I have sucky eyes and couldn't see what type of dizzy you have from your pictures.


the dizzy I am calling FB I got from a 12A with the water/oil cooler.

the dizzy I call an FC I got from a 13b turboII with the intercooler on top of the engine.

fatboy7

If you look at the rotor phases during the spark event it will make sense. Because there are two rotors, they are always physically 180* out of phase, or 360* if you look at it like a 4 stroke boinger. In the 4 stroke cycle there are 720* in a cycle, because each 'piston' (or in our case rotor face) goes 'up and down' twice. It gets really confusing when you look at e-shaft phase, and rotor phase. There is 270* of rotor phase that happens to a given face on a rotor for every 360* of e-shaft rotation. I remember reading a technical journal article that measured everything in eshaft rotation while looking at the phase of a single rotor. It was a mess because they didn't explain that the face had TDC at 540* of eshaft rotation.... nice tangent, huh.

Anyway, There are three faces to each rotor. Lets suppose that on the first rotor that the mixture is compressed, ready for spark at TDC. At the same time on that rotor you have one face that is half way through the exhaust phase, and one half-way through the intake phase.

Rotor two has a face also at TDC, but its TDC face is on the otherside of the engine (180* out of phase), during the overlap of exhaust and intake cycles. Therfore its other faces are halfway through the compression phase, and the other halfway through the expansion phase.

Now look where the spark plugs are. On rotor one, the plugs are right where you want them, in the compressed chamber. On rotor two, the apex seal divides the two plugs: the leading plug is in the expanding exhaust side, the trailing is in the compressing unburnt side. There is the problem! If you fire both the trailing plugs simultaneously, one will cause the compressing charge to ignite 180* BTDC.

The second gen coils have three coils to fix that problem. The leading runs direct fire w/wasted spark, but the trailing, which uses two coils and a toggle that directs the energy from the single ignitor to the proper plug.

fatboy7

Its OK to be confused, this stuff is confusing...

The FC dizzy, as you call it, isn't a distributer, its a crank angle sensor. Thats why it doesn't have a cap and rotor, just a pair of reluctors (one is the home signal, it only has 2 'teeth', the other has 24 IIRC, which give the ecu a better idea where the crank is exactly. The home signal gives the ecu a signal telling it that a combusion event needs to occur 'soon' giving the ecu time to prepare for the spark, and calculate when exactly to send the trigger to the ignitors, sending the spark on its merry way.

The FB dizzy has a cap and rotor, because it has to distrbute spark, hence the name. It also has a reluctor, but the construction is different, it is the trigger, sending the signal directly to the ignitors.

Because the CAS on the second gens primary objective, 'to supply the ecu with a reference signal' its signal is very different (weaker) than the signal from the reluctors in the distributer on FBs. Without a ignition computer or some very creative engineering, you have to use the FB dizzy.

rotarydankus again

i tried to post this last niteand the server gave up,i venture forth that if thesecond roter is in the intake and starting to compress when the waste spark occurs from the first rotor , that the result would BE no 180 deg early ignition on no 2 cause of the fact that the uncompressed charge is lean until compressed, so it would not fire, that is untill i boost it with my eaton, then i believe i can solve thatproblem with dual pickups and coils on the trailing side, i think that would solve it ,what do u think,

honegod

that is the theory I am working with, single pickup to dual ignitors and coils for the leading, with waste spark
and dual pickups, ignitors and coils for the trailing, for total seperate direct fire.

how do you intend to mount the second trailing pickup ?
how are you going to trigger the trailing pickups ???

the way I am figuring on is to have the trailing pickups triggered by a seperate and different "cam" {reluctor ?} on the dizzy shaft.

making that cam looks to be Fun++.

on the other hand is the toggle referred to by fatboy7, here.

"but the trailing, which uses two coils and a toggle that directs the energy from the single ignitor to the proper plug."

Jeff20B

iTrader: (13)

I've done a prototype. Trailing doesn't add enough power to justify the effort, in my opinion. I'm not vain enough to need a naked dizzy cap, yet.

Here is a simple test that anyone can perform. Swap your trailing plug wires so T1 goes to T2, and T2 goes to T1. Then try to take it for a spin (I disclaim all responsibility in the event anything should 'go wrong' during or after this test).

If you were to simulspark the trailing plugs together, it would essentially behave the same as swapping the plug wires. Try it and you'll then see why simultaneous firing of both trailing plugs is a no-no.

If you still don't believe us about trailing and its single-fire-only nature, you're welcome to keep using your setup the way you set it up. I won't keep trying to convince you any more. Good luck.

rotarydankus again

so i took your advice on step further i warmed up the car drove it with the dis trailing, then i pulled over and killed the juice to the trailing ign, drove it again and it performed better, so as a comprimise i ended up with an hei module and dis on the leadings , hei module and a msd blaster 2 coil on the trailings through the cap, car seems to run really good now, thanks for the patience u guys, i would have just went with it and not eaalized full potential ,thanks trevor

slashdawg00110

I think I follow what you did, but any chance you could make a little diagram?

rotarydankus again

im working on my presentation now ive dot to drive it also so as to make sure it holds up ill poat it asap