GM HEI: Cheap and Extremely Effective Ignition Upgrade

[klougnot]

To SchoolDaGeek,

The HEI ignition system works just fine on motorcyles. It works on Lou's KZ, Pinheads CB650, and if you don't believe me here is a video of it running on a Honda 350.

http://www.youtube.com/watch?v=RKFJgPTRlWU

The system works. Stop worrying about all the little bits and pieces hook this puppy up and run! Then you can ride your bike off into the sunset never to be heard from again just like the other forum members who got it to work for them.

[cb650]

KZ twins have done it also. Ibsens link here.

[Volker_P]

Stop worrying about all the little bits and pieces hook this puppy up and run! Then you can ride your bike off into the sunset never to be heard from again just like the other forum members who got it to work for them.

Hey! You are about to spoil an attempt to set a record here!

[SchoolDaGeek]

Gentlemen,

I have tried as many hours as I have had free this summer. I wasn't that lucky for it to work on the first time.

I don't think there is or ever was a person using the GM four pin modules and the GM Coils.

Lou published a paper he wasn't running on. I would have more information if he had simply posted his own setup.

Right now I have a 1 Watt 39W resistor to a set of opposite serial diodes to drop off 1.4v from what they are getting with enough current to simulate A/C on the start booster with a relay to coils and a relay for breaking ground to start.

Everyone else DID ride into the sunset, that is why I have no help here...or any shelter at all from the elements.

[SchoolDaGeek]

[SchoolDaGeek]

[SchoolDaGeek]

[SchoolDaGeek]

So again, I am using a single 1W 39Ohm resistor to drop current between .2 amps, tied to two sets of serial diodes to drop voltage 1.4v. Thursday Dec. 22nd I will let you know late.

[SchoolDaGeek]

Another hour and a half and no dice.

I started without the booster with positive and negative reluctors connected to W and G without start booster to check the spark as Pinhead suggested, and I had strong spark at #4 but weak and spotty at #1, which I cleaned. That BMG site has extended tip referenced NGK plugs that are used in more cars than we have bikes, so I would look into that when purchasing new...they are actually cheaper at the local parts stores and perform better. Maybe I need new plugs now.

I then went exponentially into W+ W- ought with booster, without, switched leads...I must have tried to start that bike 48 times, every single combination I could think of between the two leads of the reluctors to the W and G and off and switched, and with power and without power, etc. jumped to a running car battery. My regulator is working fine, I checked it to start.

So even a high current 39W resistor which would produce .2-.4 amps DC dropped to 1.4 volts DC through dual independent serial diodes on an AC current signal does not produce initial spark potential with a four prong module on Kellees bike at least.

The only closer signal I got was audio, as the bike stumbled under it's own ignition late in the game each time I let off the starter button, but I could not increase the length by going back through all the major connections I mentioned above, then I gave up because it was too dark to even cover the bike back up under the nylon cover.

I have half a mind to go back to stock and use voodoo pins in the module wires I cut too short.

[Deepseamdv]

I'm going to try this mod & today I got all the parts. Looking at the c849 coils how do you tell which wire connection is + or -?

[SchoolDaGeek]

Presumably, a coil acts as a resistor, not necessitating the voltage to travel in any particular direction. There is no single document I can find from Wells or any other source that indicates any polarity.

The symbol for a resistor is VVVVVVVV The symbol for coil is nnnnnnn they are both drawn relative to the circuit, meaning they can be installed in either direction. Think of those AM antennas for radios, or an incandescent filament in a light bulb, tungsten.



On my coils, there is an "H" over the right slot when turned over looking at the primary pointing towards you. I believe this would stand for "HIGH" as in HEI, or the ECM/EST breaking contact with ground and forcing the coils into their high state where they would jump to the secondary coil, through the wires, boots, and plugs, and to the ground of the threads.

The very fact that it is labeled at all signifies to me that it is the engineered location for taking the signal to fire the coils, as they will have constant voltage at the other blankly marked terminal.

I initially thought otherwise, but have had almost no response at all to my setup until I reversed the coils to wire the return path to the modules through "H" on the primary. Now I am getting stumbles when I lift off the start button.

This is because due to the tight tolerances of the coil, with only ONE HALF OHM of tolerance (.2-.7W on 200W scale to be outside of factory tolerances) the winding begins at the top and moves to the bottom. Since the secondary winding is on the other side of the coil, it is reversed, and uses wasted spark anyway, firing every 90 degrees on a normal 4 cylinder car with a distributor.

Our bikes fire two cylinders at a time, so it works out. Just like watching a Tesla Coil, the electrical spark likes to travel backwards from the first point of broken contact in the coil to the last, towards the battery.

So I would say that again, for the 7 pin modules that get constant voltage bias from the battery, it would matter less. On the 4 pin modules though, it may matter much more to get a strong properly jumped initial spark past 300rpm to get the bike started into the idle range with decreased airflow (choke).

[Volker_P]

Presumably, a coil acts as a resistor, not necessitating the voltage to travel in any particular direction. There is no single document I can find from Wells or any other source that indicates any polarity.

Correct, the impedance of a coil does not depend on polarity. So you don't have to worry on orientation how to solder it there.
The impedance however depends on frequency (rpm), usually that's why you want to use a coil instead of a resitor for some applications.

[SchoolDaGeek]

Volker I am glad you are up...what is all this nonsense then about reversing polarity on the reluctors? I never got that part.

I can understand reversing where the signal ends up on the modules, between W and G or P and N respectively, but I don't understand why exactly the signal from the reluctors are polarized?

Is the reluctor coil transverse to the direction of the passing tooth?

[Volker_P]

There you have to differentiate:

The impedance of a coil is a numerical value, independent of the direction of the field. If you reverse the field, you get the same impedance value. That' one issue.

However the reluctors (pic up coils at the crankshaft) may not be seen as a simple impedance in the circuit. Instead they are a kind of power source like a generator. Here polarity plays a role as there is no rectifier between reluctors and ignition module input ports! The polarity is given by the field (gradient) direction. So in fact the reluctors induce a voltage peak when they approch the crankshaft tip and an inversed one when they have passed and the tip goes away (induction requires transients of field either by current change or movement of magnets like here). I think there is a picture by Lou here in this thred with different peak heights depending on rpm and reluctor gaps. So this is what I am talkig about by saying "inductive voltage peak"

The Hei module seems not to do internal rectification (which is probaly a good idea) but only evaluates one polarity of these peaks to set the ignition spark. The second peak may be evaluated for other functions (rpms, ignition advance, coil charge time etc.), so in fact there may be a really good reason for no rectification.

In any case, the Hei people seem to have done it like that. Which finally means you cannot just ignore it and have to care for the polarity of the reluctors.

Reluctor coil orientation is difficult to figure out by guessing as tiny iron yokes may be present to guide the field. However no real need to know about the reluctors orientation. It is a fact that the voltage is reversed when you change the terminals.

Hope one can understand this.
Note that I only have some basic ideas but do not know the details to the Hei stuff. So please don't fix me on details. I assume everything may be deduced from Lou's and Pinheads posts somehow, but this seems real work.

[SchoolDaGeek]

Ah I see the difference!

For general purposes the "generator" example is easiest to understand as in a sine wave. We want the sine wave to lead on the positive plane and finish with the negative.

It is so interesting how coils, transformers, am antennas, and generators all work differently, when they are so physically alike.