'82 450 Igniter - Repair, Replace, or Make?

[bakalorz]

I'm going to put my comments in red, cause its otherwise hard to make multiple quotes in the middle of it all

I think you're both right, in that yes the dwell on the HEI module is adjusted by the bias on the W connector, but there is also dwell in relation to the pickup coil. I don't fully get the whole dwell thing, but I do see that both the W and pickup coil come into it.

Martin, when I hooked it up last night, I was connecting W to 12v like the points setup on Lou's page showed, so was this actually wrong and I should've left it disconnected?

No, that was the right way to do it. if W is connected to 12v its effectively not being used. when you use W to adjust the dwell its hooked into the input circuit somewhere.

The other thing I'm looking at now is the unconfirmed GS450 ignitor schematic.



I can't read the component values on there, but it seems they use a 1K resistor combined with maybe a 3.8K resistor, a zener diode, and maybe a 0.22uF capacitor to couple the pickup coil to the base of the transistor, and a 4.7K resistor is also used to connect to the collector.

I can't read it, so can't really comment much, what are the wire colors coming in representing. I got the impression the Zener is not on the input but providing a refrence voltage for something.

I do actually have some zener diodes, but I don't know what type they are or if that actually matters.

The zener value has to be right for it to do what it should, they are NOT interchangeable

Is it worthwhile trying this setup at all? I can't get my brain around how that should work though.

That looks like it is the whole igniter ... you would not use the HEI modules with it.

There is also the attached schematic the German fellow did that uses a 47K resistor in conjunction with a diode to couple the signal to the base of the transistor, and this one I can actually sort of comprehend.

I like the way he couples the signal in, its worth trying replacing the cap and 280 ohm resistor with a diode as he shows as an experiment

I'm not trying to second guess any of your ideas here either guys, I'm just trying to get my brain around it all and at the moment I'm not succeeding at all.

I am not familiar with the ignitior, I started reading the thread to learn more than anything else ... I only started commenting because I thought an Opamp was probably the wrong way to go ... I'm only guessing ... somewhat educated guesses, but just guesses.

I also now am thinking that my perceived need to invert the signal is actually not quite right.

For the positive going signal to fire a spark, it needs to turn the coil off, which means the transistor needs also to be off. Does that sound right?

So going just by the German fellow's circuit, normally T1 will be off and T2 will be on, meaning the coil will therefore be on.

I'm not sure ... His D3 and D4 allow the coil voltage to influence the base of the last transistor, so that may complicate things.

When the signal generator generates its tiny positive going signal and therefore raises the voltage slightly on the negative side of D1, this turns T1 on, thereby turning T2 off, and therefore firing a spark by turning the coil off again.

I imagine this is also the exact same theory behind your two transistor setup too Martin, so probably that's what I should've been trying.

With the two transistor amp, it should be biased so that normally Q4 is off, so that Q3 is on, so that the module is off.
when the signal generator generates its tiny positive going signal it turns Q4 on, turning Q3 off, turning the HEI and coils ON
When the signal generators tiny positive going signal stops, Q4 turns off again, Q3 on, and the HEI kills the current to the coils ... and then it sparks, as the tiny positive going signal ENDS

Sorry for my confusion here and if it's making you guys confused too...

 

[Guest]

Ok wow, I think my head just exploded... but again in a good way

I should've clarified that when looking at the ignitor schematic and the German fellow's circuit, I'm only really looking at the first two transistors as everything after that I expect to be covered by the HEI module.

I just tried cranking some more to get a good signal, and the best I could get was a replication of the earlier positive going 80mV signal.

So, I'll next try with the diode and 4.7K resistor (R6) feeding the base of Q4 (in your second schematic), I'll drop R7, and I'll use a 5.6K in place of the 4.7K R8. I'll leave R5 as is.

And yes, I'll do the 5.6K on both circuits for sure.

I think I got what you're saying in relation to biasing Q4 so it is off.

Also, I really do appreciate your help here, and I'm aware that my lack of understanding is making the whole thing harder than it should be. I have every intention of following through on this and making it work like it should.

Thanks again.

Hopefully I can test again in the next day or two as I need to get ready for the funeral shortly.

 

[Guest]

Sorry, R6 should be 47K rather than 4.7K I just realised... or should it still be 4.7K? His R2 (your R5) are quite different, so I should probably stick with the 4.7K's.

 

[Guest]

Ok, attaching the next schematic to try which is the combination of the German fellow's pickup setup with Martin's setup.

 

[john82q]

over thinking?

over thinking?

Pete, (and Martin)

I think your making this harder than it needs to be, Pete, your a computer guy down load some SPICE software and have a fiddle with these circuits, and some transistor examples, im sure in no time youll understand better.

I have used LTspice before ages ago, I down loaded a new copy tonight its come a long way. I quickly made 2 circuits, the values (componets) are nothing particular, and thats the value of a simulator, nothing goes pop and you can plug in values based on what you have at hand and work up a solution from there. ( you simply draw the circuit the software does the math) .

"W is normally the terminal providing the bias voltage to the negative side of the pickup-coil."

According to lou's notes W is a reference voltage and can be used for adjust the dwell, tying it to 12 v disables it,just leave it disconnected, don't worry about it till after you get her running.

Now I still belive all you need is a 0 heading pulse attached is how to use a opamp without a negative supply, the zeners optional it is there because I have a bad feeling about the input using 12V.(i could be wrong I there I know sweet FA about the HEI)

V1 is the 12, V2 across pickup, "out to the HEI G" B to 12v and C to the coil (-ve)


Now humour me and try the opamp idea attached...


John

 

[bakalorz]

Ok, attaching the next schematic to try which is the combination of the German fellow's pickup setup with Martin's setup.

Thats about what I would try, although I would try it without R3 first.

 

[bakalorz]

Thats about what I would try, although I would try it without R3 first.

Also, one addititonal comment:

You said you have a bunch of the transistors, but didn't mention diodes ...
If you dont have any diodes handy, use the base/emitter junction of an extra transistor. just connect the base of the extra to the base of Q1, the emitter to the pickup coil, and let the collector float.

This is theoretically better than using the diode, since the idea of using the diode is just to add enough bias to compensate for the base emitter junction of Q1 anyway ... and using another similar transistor means that this will be matched better than with a diode which may have a slightly different drop.
(if you look at your figure, you'll see a teensy little diode drawn on the emitter of Q1)

Also, re-reading Lou's notes, if you connect W to 12 volts, you definately don't need R3.

 

[Guest]

Pete, (and Martin)

I think your making this harder than it needs to be, Pete, your a computer guy down load some SPICE software and have a fiddle with these circuits, and some transistor examples, im sure in no time youll understand better.

I have used LTspice before ages ago, I down loaded a new copy tonight its come a long way. I quickly made 2 circuits, the values (componets) are nothing particular, and thats the value of a simulator, nothing goes pop and you can plug in values based on what you have at hand and work up a solution from there. ( you simply draw the circuit the software does the math) .

According to lou's notes W is a reference voltage and can be used for adjust the dwell, tying it to 12 v disables it,just leave it disconnected, don't worry about it till after you get her running.

Now I still belive all you need is a 0 heading pulse attached is how to use a opamp without a negative supply, the zeners optional it is there because I have a bad feeling about the input using 12V.(i could be wrong I there I know sweet FA about the HEI)

V1 is the 12, V2 across pickup, "out to the HEI G" B to 12v and C to the coil (-ve)


Now humour me and try the opamp idea attached...


John

You're right on my part John, I have been known to over think and over complicate things every now and then...

So the circuit attached... I assume a 741 is suitable for whatever that particular op amp is?

I have some zeners, but I need to identify them as I can't remember if I had them for 5v work or 12v work.

I definitely agree with your statement about the 0 heading signal though, that is definitely what I need.

My only question on this is in regards to getting the coil to turn on first though, and is it safe for the coil to leave it on all the time between pulses from the signal generator? Perhaps I'm not getting something here still...

I just downloaded LTSpice myself and will have a play with that also.

Now that you mention it I do recall Spice software from years ago myself, but I never actually used it, just new it was good for simulations.

Also, one addititonal comment:

You said you have a bunch of the transistors, but didn't mention diodes ...
If you dont have any diodes handy, use the base/emitter junction of an extra transistor. just connect the base of the extra to the base of Q1, the emitter to the pickup coil, and let the collector float.

This is theoretically better than using the diode, since the idea of using the diode is just to add enough bias to compensate for the base emitter junction of Q1 anyway ... and using another similar transistor means that this will be matched better than with a diode which may have a slightly different drop.
(if you look at your figure, you'll see a teensy little diode drawn on the emitter of Q1)

Also, re-reading Lou's notes, if you connect W to 12 volts, you definately don't need R3.

Yep, I have a bunch of diodes, 1N4004 from memory.

And yep, I see the diode

So, connect W to 12 volts and ommit R3... got it... although I think I will also try what John suggested and leave W disconnected and use R3 so I can see if either way is better.

Thanks again guys, I don't expect I'll get to try any of this until tomorrow night but I'll definitely let you know what I find.

 

[john82q]

pete
I'm thinking coil wont be on all the time, as the module controls it.
my take any way. (dwell = coil on time)

if you dont have a zener use a resister, all its doing is provideing feed back to set the amps gain.

LM471 will be fine

sent you a PM with my email respond and i will send you the ltspice file save you drawing it.

john

 

[Guest]

Cheers John, got your PM and sent you an email.

Just waiting for some couches to be delivered so I can bust my back getting them up and down stairs (love moving furniture) so checked on here while I'm waiting.

Hopefully tomorrow night I can get stuck in and try some things.

 

[john82q]

LM471 will be fine

just wanted to say, no it wont, well not with tweaking, sorry if i wasted any of your time.

john

 

[Guest]

just wanted to say, no it wont, well not with tweaking, sorry if i wasted any of your time.

john

Haha ok cool, explains why it didn't work as expected, and no probs on wasting time, didn't spend long on it at all.

I actually did get in there tonight as my wife's still a bit seedy after last night due to a few of her ex work mates coming back here after the funeral yesterday.

Anyways... I hooked the 741 up and ended up with 3.1 volts at G on the HEI module which is not what's supposed to end up there at all, was expecting more like 1.6 volts. Cranking produced no spark funnily enough...

So, I went with the revised diagram with the two transistors and the diode as the bias, but still no joy. I've attached the revised diagram.

Cranking was not giving me a nice signal on G still, so I'm not sure where I was going wrong with this one at the moment.

At this point in time, unless I can get some real daytime time to work on it when I can crank and play with the circuits, I can't see me getting any further unfortunately.

However, I'll think some more on this as I'm wondering if doing it this way requires a different hookup of the HEI module.

I do recall when being used with a distributor on a car, that W and G both connect to the distributor, and my initial testing of the HEI module was a AA battery with negative to W and positive to G to fire a spark.

I'm wondering now if I should ditch Q2, connect W to the collector of Q1, and G to the emitter of Q1 rather than the emitter going to ground (or something like that anyway).

I'll obviously need to increase the amplification for that too.

I'll try to find the diagram again that the manufacturer has of the distributor hookup.

Of course I could just be way off track here too...

 

[Guest]

Actually, my last comment at the end there ain't gonna work at all. If what I think is right, then the collector and emitter voltages will just float somewhere near 12 volts.

I'm also tempted at the moment to ditch the whole HEI module thing and go with the German fellow's ignitor circuit.

However, I (and you guys) have already invested alot of time in the HEI modules so I should persevere... it's just frustrating (and I'm impatient).

 

[john82q]

Proving frustrating...aye..

At this point in time, unless I can get some real daytime time to work on it when I can crank and play with the circuits, I can't see me getting any further unfortunately.

may be you will need to make a test rig, either something you can spin or a quiet motor, with the pickups off the bike. I can see the testing being quite time consuming.

Your welcome to come around tomorrow arvo and we can knock something up if you like. (i have the means)

john

 

[Guest]

Proving frustrating...aye..

may be you will need to make a test rig, either something you can spin or a quiet motor, with the pickups off the bike. I can see the testing being quite time consuming.

Your welcome to come around tomorrow arvo and we can knock something up if you like. (i have the means)

john

A test rig would be great but I definitely don't have the means myself at the moment.

This avo's out unfortunately, need to go into the city to do a couple of things.

However, if you're still free and willing next weekend, then I should be able to organise something.

Thanks for the offer of help again too, greatly appreciated. I'm also more than happy to repay in beverages of your choice as well...

 

[Guest]

I got some action!!!!!

I got some action!!!!!

John, I tried your updated 741 circuit to no avail, and in case my signal readings were wrong in that I do get negative as well as positive signals, I tried both variations.

Then, I got so frustrated I just went bugger it and back to the beginning...

I know that when I put a AA battery's negative to W and positive to G, when I let it go it gives me a nice fat juicy spark.

I also know that the stock ignitor sparks with a positive going signal.

I also want dwell to be controlled by the pickup coils, rather than having to stuff around with biasing the HEI module if I can avoid it (I want simple stuff).

So, working with 0.08v as my input, I decided the most simplest and straight forward way is to go back to the original suggestion of a simple transistor circuit to both amplify and invert the signal.

I played around with LTSpice (thanks again for the heads up on that one John) and used the diode coupling from the German fellow's ignitor circuit to couple the pickup coil to the BC547.

I played around with random resistor values (I won't pretend to know what I'm doing here) and ended up with the attached circuit.

LTSpice showed me an inverting signal dropping from 12v to ground which is definitely right for firing the HEI module and avoiding any ambiguity.

I hooked it up on the breadboard for both pickups and coils, and just cranking by hand quickly enough fires a spark every single time as it should.

So, my question is... even though it appears to work correctly in terms of sparking every revolution, what are the drawbacks of this? Any clues?

If the amplitude of the signal increases with RPM's (which I expect it will), will that have any detrimental effects? I increased it to 1v in LTSpice and it looked ok, but of course it's hard to tell.

I will say this much though... geez it feels good to give it a crank just by hand and see those nice big blue sparks

 

[john82q]

well done Pete.

At least your ambition hasn't exceed your ability! (thats gotta be an all time quote from casey)


Will be interested to know, I see this time you've grounded W, does it make any difference if its disconnected?

john

 

[Matchless]

Pete,
I have been following your progress and just want to say: "Excellent job"!:clap:

The main test will be when running at idle and high RPM's and using the bikes battery which fluctuates at varying RPM's.

The sparking on every revolution should be no problem at all, as that is what the OEM and the German schematic does as well.

Well done!

 

[Guest]

well done Pete.

At least your ambition hasn't exceed your ability! (thats gotta be an all time quote from casey)


Will be interested to know, I see this time you've grounded W, does it make any difference if its disconnected?

john

Cheers John! A very happy man is I. As for exceeding my ability, well, that remains to be seen yet, but I certainly couldn't have gotten where I am without yours (and others) assistance.

The proof is in the pudding as they say, and hopefully this Saturday can be first start day...

I'll test with W disconnected tonight or tomorrow night and see what the difference is (if any).

Also, if you're referring to Casey Stoner, then say no more! I taped the GP last night as Barry wasn't up to staying awake for it and I wanted to keep going on the bike, so I'll try to avoid all the news today and watch it tonight.

Pete,
I have been following your progress and just want to say: "Excellent job"!:clap:

The main test will be when running at idle and high RPM's and using the bikes battery which fluctuates at varying RPM's.

The sparking on every revolution should be no problem at all, as that is what the OEM and the German schematic does as well.

Well done!

Cheers Matchless, but I take no credit.

If it wasn't for you guys and especially Martin and John, then I'd still be scratching my head and contemplating spending a lot of money on a Boyer Bransden or Dyna S.

I'll need to check the timing yet and definitely need to see what it's doing throughout the rev range.

 

[Guest]

Very nice Pete. Now this is getting interesting. You have spark. :clap:

Both FC and me have been working on the GS450, trying to get it to spark. It has been confirmed that the igniter is the problem. We have another 30 year old igniter on our way hoping that it will work. But I have a feeling that it will not. If that fails, we will have to try using these GM HEI modules. Neither of us are good with electronics though. I will have to read over this whole thread again. Keep going!

Well, I'm having reserved celebrations at the moment... I need to actually get the engine running and revving first to see if it works properly or not, and I have a few more tests to do as well, so I wouldn't recommend building one based on this thread just yet

But don't worry, once I know the deal, a proper build write up will be done and I will ask BassCliff to see if he's willing to pop it up with the rest of his stuff. If it works like it is, there'll be a whole 4 components per module with a total of 9 soldered connections per module, so it won't be hugely difficult as long as you can follow instructions and probably use some imagination.