Lynn E. Hanover

Before I was "saved" I raced a Fiat Spyder. Pretty cool twincam 1800CC.



I ran a crank trigger with the Chrysler pieces. The pickup has two leads and a nice connector plug on the end, so I used the whole thing. We had 250 PSI cranking, so it could kill a starter trying to start it with 35 degrees in place.



So I added a chrysler reluctor wheel to the stock points style distributor. I ran the wires from that pickup and the wires from the crank trigger to a double pole, double throw AC switch on the dash. I ground out the advance slots, so I could start the engine with 5 degrees of advance. That way I had two sources for triggering the amplifier. Both the distributor and the crank trigger would give 35 degrees at full tilt.



You could do the same thing on a rotary with the stock distributor or the crank angle sensor and the stock crank reluctor wheel. I am lost from this point because I am not at all famillier with the computor stuff. But it can be done without too much trouble. Then you can drive around on the recommended curve and advance. Then stand on it and once above the max advance of the stock curve, you have max advance you want. Or you could change it around to retard when the nitrous comes on, or after X amount of boost comes in. Even do it with as manifold pressure sensor.



In a 4 rotor, you can run the two rear housings from the crank trigger, and the front two from a stock distributor or crank angle sensor, or the stock reluctor wheel with a bit of electronic tomfoolery.



I run an electronic distributor with just the leading pickup connected to both the leading and trailing MSDs. No stock igniter. Just a shielded pair of leads (in a dash 4 braided hose) to the MSDs. It is just too easy. When I get some time I will return to the crank trigger system timed off of the flywheel.



When we got the first Mazda electronic distributor, I hooked it up using the stock igniters that came bolted to the sides. I was trying to run split timing with it, and the trailing timing would bounce back and forth between 25 degrees of the leading and the 20 degrees I wanted.



I asked another Mazda racer about this and he didn't even look up. He just said "your using those stock igniters!" "Throw them away". Not only would they pick up signals to fire from each other, they could be triggered out of phase when the rear housing fired, and kill the engine. Mazda later moved them to the fender to get them away from the secondary ignition wires, with some success. Then gave up all together. With a powerful CD or MSD added, it was a disaster.





Lynn E. Hanover

CGeek2k

What kind of signal is the pulse coming out of the CAS, connectivity, voltage, etc? And what wires is it on? I ask because I am trying to use a CAS off of my parts car to measure the speed of something. I have a cheap datac unit that has 0-5V analog inputs and can be programmed to count pulses if I knew how to set up the circuit. I have used a small multimeter to check for connectivity between the red and white wire pair and the green and white/black wire pair but I cant find any change in the resistance when the CAS is spinning or stopped in any position.



Sorry about the thread jack



Thnx

Andy

bill shurvinton

Its a variable relutance sensor, so voltage out is proportional to speed. At a couple hundred RPM you will get about 2V. At a couple of thousand you will have about 100V.



For you application it would be worth using a J109 ignitor as an interface. In this case the output that normally connects to the coil would be used as an open collector line.

Apex13B

i have been comtemplating a german style coil on plug system, using a crank "buzzsaw" from a cosworth DFV for quite some time now.

j9fd3s

the rx8 actually has a system like this. its got one pickup and a trigger wheel on the front pulley. the pickup is a really funky shape, but it bascially tells the computer where the engine is in its cycle

Lynn E. Hanover

Ok, I just checked that out. The 90 degrees, 180 degrees are OK. The spark is still in the exhaust cycle. The next 90 degree point is at 270 degrees and that is also 90 BTDC on the next rotor face. So another spark at 270 is out of the question.



So there is that answer.





The stock coil running a "lost spark" system (so they don't have to buy another coil) Fires one housing at (whatever BTDC) and the other end of the coil fires housing 2 at a point way late in the exhaust cycle so it has no effect on performance. So late in the exhaust cycle, there is little pressure, so there is a good arc (conductivity) on that end, and the plug in the firing housing is more likely to fire.



A basic rule is that the higher the cylinder pressure, the higher the voltage it takes to get an arc across the plug gap. So higher voltage and shorter gap, or, both.



As a NA engine revs up, the actual cylinder filling goes down. In other words, each cycle has a smaller volume of fuel air mixture to compress, so (A) the compression ratio is going down. And (B) Even without the compression ratio changing, the smaller volume of fuel/air would make less power anyway. So we could get past 9,000 RPM with a breaker points distributor. in a NA engine.



With no turbo, this only means that I run a leading plug gap of .010" to .015" on Ice cold NGKs ($25.00 each). The trailing are protected from the charge speed so the gap dosen't seem to bother that too much. The rotor drags the fuel air mixture past the plugs at the speed of a rifle bullet. The chance of this working at all is remote. So the rotary used at high boost, with nitrous, at high RPM etc. May have a problem with the ignition system.



If you have a high speed problem, like it feels like a rev limiter or kind of goes flat above a certain RPM, (because the leading plug can misfire and unless the trailing also misfires, you won't feel it) try a set of cold plugs gapped at 0.010". If the problem goes away or moves up in the RPM range, you need more spark energy.



An over rich mixture is easier to light than a over lean mixture. The MSD was first used on Chrysler V-8s called the (Lean Burn engines) They were jetted so lean that without the MSD they would not run at all.



So if you can control mixture, make it richer and if it runs better you have three choices. It needs more spark energy, and, or, it was too lean.



MSD has a manual sold at hot rod shops that is full of useful information. Pick it up when you go in to buy the giant degree wheel.



If you run one coil to drive both plugs on one housing, it is likely that you will have to shorten the leading plug gap, or both gaps. And for turbo installations, even drive the coil with an MSD.



Lynn E. Hanover

Jeff20B

Yep, there is a 270º problem, but I figured out a way around it with a crank triggered ignition. Here is a quick little diagram. Each leading pickup will be mounted 180º opposite of each other. There will be a magnet at each area of the pulley where I marked it with a degree (0, 90 and 180).

Jeff20B

And if you're gutsy enough to attempt this in a distributor, here is what it might look like.



Note, this is what it MIGHT look like. I think the leading pickups would have to be spaced 90º apart.

Lynn E. Hanover

I have never done anything with the stock igniters once I had cross fire problems.

I took them off and have never thought about them again.

I wouldn't recommend them to anyone.



I did the first version with Chrysler pickups and amplifiers.



Then again with MSDs.





Lynn E. Hanover

Lynn E. Hanover

How about this.



Four pickups at the four corners of the compass.



one reluctor.



Two pickups (say at 9 o'clock and 3 o'clock) run the front two housings, the same as I ran mine.



The second set mounted at 12 o'clock and 6 o'clock run the rear two housings.



If the timing retards as you rev the engine, reverse the leads from the pickup.



You have to check the timing on all four housings. I moved the pickups in slotted holes to adjust timing.





Lynn E. Hanover