# S / S CDI ignition system



## cfellows (Mar 22, 2010)

Just wondered if anyone has any experience with the S / S CDI single spark ignition system? For $50, which includes the coil, it looks like a pretty good deal. Any thoughts?

http://www.cncengines.com/orderpage.html

Chuck


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## doc1955 (Mar 22, 2010)

I just recently ordered that unit it looks like it will work out nicely.
As a matter fact I was going to start a new project creating a small ignition box using it.
Just haven't found time yet. When I do I'll post my progress.













Took these with the laptop camera
I ordered and they must of shipped the same day they were very pompt at getting it to me right away.


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## ghart3 (Mar 22, 2010)

Think it is the greatest.  Just goofed and left the ignition on for a week.  Engine started right up.  It is small, doesn't need big batteries. Using 4 rechargable AAs. Runs for long time on those batteries. The most trouble free ignition system that have ever had.


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## GailInNM (Mar 23, 2010)

Chuck,
Arv (PutPutMan) used one on his recently completed "Tiny" as shown in the thread at:
http://www.homemodelenginemachinist.com/index.php?topic=8096.0

He seemed to like it quite well.

I have one to put into my "Tiny" build in a few weeks.

Gail in NM


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## Longboy (Mar 23, 2010)

.....I have that ignition Chuck on a Breisch Hit Miss I bought on Ebay this winter. I got the $100 kit. Works well and the 4 AA battery pak is bigger than the board and coil assembly. Fits in a shallow 3x5 box. The model ignition coil and C cell battery holder on the Webster engine obtained thru Ebay cost me $32 w/out batterys. Can't beat the compact size either type.  Dave.


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## putputman (Mar 23, 2010)

Chuck, that unit was recommended to me by a friend. I called S/S and talked to Roy Sholl. Explained to him that I knew nothing about electronics. He recommended that I buys the complete unit the first time. It included the coil and all the stuff the $50. unit has plus the battery holder, batteries, charger, switch with a charging pigtail, and all the necessary Futaba connectors. 
We later spoke on the phone and he walked me through all the necessary connections.

I will buy the $50.00 units in the future as I now have the chargers etc.

I personally have never worked with a supplier that is so cooperative and helpful as Roy.


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## b.lindsey (Mar 23, 2010)

Chuck, I don't have any personal experience with these yet, though it has been recommended to me also by someone whose opinion I trust. I am planning on using it on the Briggs build myself though I haven't purchased it yet, so will be following the comments of others here with great interest.

Bill


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## cfellows (Mar 23, 2010)

Thanks for your input, everyone. Looks like I will be ordering one of these for my Henry Ford engine.

Chuck


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## stevehuckss396 (Mar 23, 2010)

Hi Chuck! 

That is the same ignition that I used on the Peewee. They are awesome!!


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## ariz (Mar 23, 2010)

I bought the same system from a UK supplier, Apache

assembled in few minutes and it worked at the first try: the spark plug that I built myself showed a nice blu spark at every passage of the magnet over the sensor

unfortunately the engine didn't run at all, but the CDI ignition system was worth every pound that I spent


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## slick95 (Mar 23, 2010)

Chuck,

Great ignition system. Completely trouble free and reliable. Used it on my Odds N Ends H&M engine:

http://www.homemodelenginemachinist.com/index.php?topic=7773.45

And Roy is very helpful if you have questions or need advice.

Jeff


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## Rustkolector (Mar 23, 2010)

I have used one of Roy's CDI ignition systems for a year now with complete satisfaction. I asked him to put a remote LED on the ignition to aid in timing as well as an indicator that the system is working. A good add-on. 

Jeff


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## Diy89 (Mar 24, 2010)

Another vote of Go and buy it. It is a Great company to do business with. Excellent products and 
Great no, Fantastic service.


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## cfellows (Mar 27, 2010)

Thanks again to everyone for the informative responses. I did order and received the basic single spark system along with the spark plug boot and wire. The latter, by the way, is a pretty slick arrangement.

So, I want to mount the ignition module to the wood base on the underneath side of my plumbing parts engine. Can you fellows give me some hints on how to mount the ignition board? There's no holes for screws. Also, I'm not sure if the board can be enclosed or if it requires good ventilation for cooling.






Thx...
Chuck


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## putputman (Mar 27, 2010)

Chuck, I used Velcro to hold my coil unit under the Tiny I.C. engine. The base is also enclosed and so far it hasn't been a problem. I don't run the engine very long at one time.


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## ghart3 (Mar 27, 2010)

For a 4 cyl engine, 
Roy said that ventilation wouldn't be needed and fairly sure he is right.
Milled out 3 pockets. 

One for the ignition module.

One for the wiring connections and the LED light to show ignition is on. Led fits in hole to rear to the back side.

The last one is battery compartment. Base can be slid off of end of table to expose open area and batteries changed while base rests on table.  Simple screw in switch makes contact with plus terminal of battery for on/off sw.

Each compartment has thin piece of Micarta screwed on to hold things in place.






Ignition wires for hall sensor run up square tube on one side and the coil wire runs up the square engine mount tube on other side.


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## cfellows (Mar 27, 2010)

putputman  said:
			
		

> Chuck, I used Velcro to hold my coil unit under the Tiny I.C. engine. The base is also enclosed and so far it hasn't been a problem. I don't run the engine very long at one time.



That's a good idea. Did you just glue one half of the velcro to the bottom of the board? Also, how do you turn it off and on?

Thx...
Chuck


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## doc1955 (Mar 28, 2010)

I put together a box for mine. You can tell I'm not a wood person the box didn't come out real pretty but it hold the stuff together. I have it set up with a bayonet plug in for the spark wire and a 2 wire jack for the ground and the sensor wire it has a green pwer LED and a micro toggle switch. This way I can use it with more than 1 motor I took a little video with my wife's Ipod on my this is the first time I've had my odds and ends engine running in a long time. I was playing with the CDI module and was amazed it will actually throw a spark between contacts about a inch apart! I am very impressed with this unit I may just order another one.

[ame]http://www.youtube.com/watch?v=a1-gSRgTfZs[/ame]


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## putputman (Mar 28, 2010)

Chuck, I used a Velcro that had a sticky back on both pieces. It stuck quite well even after I removed the Velcro and put it back on several times.

When I bought my unit from S/S, I purchased the complete package. It included the batteries, charger, on/off switch with charging pigtail, coil, and hall sensor w/magnet. Later I ask Roy if he could fix me up with a LED that I could tell if power was on or off. He made up a LED with a pigtail and Futaba connector that plugged in between the battery and the coil. Sent it to me free. 

The extra pigtail on the switch allows you to charge by shutting off the power and not removing any other connections.

I think any of these components can be purchased separately.


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## cfellows (Mar 28, 2010)

Thx, Doc, I considered making a separate unit, but decided against it since I don't have multiple IC engines to run with it.

Gary, I like the looks of yours, very tidy. However, I don't want to take the engine apart to mill out the bottom of the board, so, I'm going to use Arv's suggestion and just velcro the circuit board to the underneath side of the engine. I will keep the battery separate so I can just unplug it to turn the unit off and also to recharge it.

Thx everyone...
Chuck


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## Rustkolector (Mar 28, 2010)

I routed out my wood base to hold the ignition module and battery back. Both are installed using red 3M heavy duty double faced tape. It is about 1/16" thick, soft, and holds very well. I also use it to hold pieces to the lathe face plate. I have run my unventilated system for hours on end at shows with no ill effects, or overheating. 

Jeff


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## cfellows (Apr 4, 2010)

I was doing some troubleshooting yesterday on my plumbing engine (wouldn't start) and I pulled the plug out to see if it was firing. I discovered that the S / S CDI ignition module fires twice, once when the switch closes and again when it opens.  Has anyone else observed that? Just wonder if that's normal operation. I'm using a micro-switch instead of the hall affect transistor...

Seems like that could potentially be problematic if my ignition is firing at the beginning of the compression stroke, where the switch closes and at the top of the compression stroke when it opens.

Chuck


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## putputman (Apr 4, 2010)

Chuck, I was having the same problem when I was using points on my Tiny I.C. engine. I talked to Roy Sholl about it and he said it is not supposed to do that and he couldn't understand why it was happening. I made a video of it for him to look at but he said he couldn't bring it up on his dial-up internet. 

I felt it was a wasted spark but I couldn't control the timing with it that way. I finally made a new cam with a very short contact time and rotated it so the first ignition was at TDC and the 2nd would be during the power stroke where it wouldn't hurt anything. It was just too hard to control.

I switch to the Hall Effect & Magnet and the engine took off and has run good every since. I just assume I had a defective unit but being it ran OK with the Hall, I wasn't going to pursue it any more.

I think you should contact Roy and explain it to him. He obviously has a problem that should be fixed. 

I hope he is at N A M E S so I can talk to him a little more about the problem. I plan to buy some more units, but I would like them to run with breaker points.


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## doc1955 (Apr 4, 2010)

I noticed the same what I've done to try and address this was to do the same made the trow on the cam more and have a larger point gap to the point where the points just touch this creates a almost zero dwell for the points being closed. It seemed to help a lot with the double fire.


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## ghart3 (Apr 4, 2010)

Just a thought.  If there wasn't a clean break when the points open maybe the ignition module sees a open - close and open again as the points are opening. It is advertised  "MAXIMUM SPARKS PER MINUTE = 12,000"


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## cfellows (Apr 4, 2010)

ghart3  said:
			
		

> Just a thought. If there wasn't a clean break when the points open maybe the ignition module sees a open - close and open again as the points are opening. It is advertised "MAXIMUM SPARKS PER MINUTE = 12,000"



Yeah, I wondered about that too. Thought maybe the switch was bouncing. 

Chuck


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## putputman (Apr 4, 2010)

Chuck, when I talked to Roy, he suggested it might be a bounce. I took a video while turning the engine over by hand. It is not a very good video but it does show that a spark occurs when the points make and again when they brake.

I'm convinced it isn't bounce.


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## cfellows (Apr 5, 2010)

Yeah, I see what you mean on the video. I was turning my engine over by hand, pretty slowly when I detected the double spark. 

Chuck


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## putputman (Apr 14, 2010)

Chuck, I have been wondering if you ever resolved the double spark problem. Did you talk to Roy Sholl about the problem?

I finally got my drag saw up & running with the Red Wing engine driving it. Now I want to paint & remount all the components on a new frame. At the same time I was thinking to switch the ignition system from the old ford coil to the S / S CDI unit but I would like to still use the point system rather than Hall effect. 

I will be at NAMES next week and will talk to Roy if he is there. I was hoping you have contacted him also so he realizes mine was not the only unit that had a double spark.


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## cfellows (Apr 14, 2010)

Arv, I've not contacted Roy about the double spark problem. Near as I can tell, it's not causing a problem. However, feel free to give Roy my name if you'd like. I'm using a microswitch activated by a cam.

Chuck


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## cfellows (May 2, 2010)

Arv, did you get a chance to talk with Roy at NAMES about the double spark issue on his coils?

Chuck


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## Ctmouse (May 7, 2019)

I'm in need of some direction as I need a new ignition System for this mini Tractor Motor it has a set of points Condenser and a coil from a lawn mower (the coil is bad) this was used to provide spark to a NKG CM 6 Plug I was using a small 12 volt battery for the coil Which I believe I fried the coil! I'm in the begining stages trying to bring this back to Life.
This was built my an uncle way back in the day and has sat in the basement for decades now. I really Don't have much history on it other than it did run back then. after some research it appears to be a version of a HUMBLEY Oil Pull tractor. I am hoping to replace the ignition and get it to run again. I believe this would be just an air cooled motor that has forward and reverse capabilities. ant help on this project or suggestions would be greatly appreciated.

thx Rick


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## bluejets (May 7, 2019)

Did you see my writeup from a few months back?
https://www.homemodelenginemachinist.com/threads/model-engine-cdi-easy-and-cheap.31128/#post-322284


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## rsholl (May 8, 2019)

cfellows said:


> Arv, did you get a chance to talk with Roy at NAMES about the double spark issue on his coils?
> 
> Chuck



Hi Chuck and fellow model builders,

NAMES was crazy busy on Sat. so I'm not sure who all I talked with.
To address the problem Chuck is having and also with some reed switches and points set ups. My CDI is triggered via a logic circuit. What that means is, the WHITE wire, by what ever means, must be pulled to ground. When it is released the CDI fires the coil. What I have heard and seen over time is when the CDI fires when the points close, it is due to point bounce OR the points MOVING when they close. This bounce or rubbing action can only be seen on an Oscilloscope. The logic circuit in the CDI is very sensitive and can detect closing and opening in the micro second and possibly even nano second range. So, any switch that is not 100% clean when they make and break can trigger the CDI. For the past year, I have instructed anyone with a points issue to set the point gap in the .003" range. The CDI does not have dwell time like the old Kettering system does. My logic being, if the points don't have to move far, then there is less chance they could bounce or slide together. I have also tossed out the idea of using a switch/points that are NORMALLY CLOSED and open only when you need the spark. The CDI doesn't care which state it is in most of the time, it just needs to change. The WHITE wire is logic HIGH and if it is held in the ground condition and only released when a spark is needed it should  fire the engine reliably. This doesn't mean it won't fire when they close again but it would be after the correct spark timing and should not be a problem. Now that the new Version CDI is finalized I hope to be able to spend some time looking at remedies for the erratic operation of some micro-switches and points. I hope a small value capacitor on both the micro-switch and some points setups might eliminate the erratic firing. On most electronics with mechanical switches there is software that debounces the switch and that includes push button switches. I could program a module similar to the one used to convert our single spark to a buzz coil but that would be over kill. I am always glad to get feed back from anyone and know I have not kept up as well as I should have. It has been a struggle over the past 2-3 years with the CDI because manufactures kept obsoleting parts. With the new version CDI, I am having the transformer wound here in Ohio and I am hand soldering the components on the board so now we have complete control over the manufacturing of the CDI. If anyone has tried the normally closed points set up, I would definitely like to hear from you. I do get email updates when someone posts and now I hope to be able to keep up with what's going on. I hope this sheds some light on how the CDI operates. The reason we don't see this with the hall sensor is because it is not mechanical and by design it is in one of two states, either ON or OFF, nothing in between.

Regards,
Roy Sholl


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## bluejets (May 8, 2019)

rsholl said:


> Hi Chuck and fellow model builders,
> 
> NAMES was crazy busy on Sat. so I'm not sure who all I talked with.
> To address the problem Chuck is having and also with some reed switches and points set ups. My CDI is triggered via a logic circuit. What that means is, the WHITE wire, by what ever means, must be pulled to ground. When it is released the CDI fires the coil. What I have heard and seen over time is when the CDI fires when the points close, it is due to point bounce OR the points MOVING when they close. This bounce or rubbing action can only be seen on an Oscilloscope. The logic circuit in the CDI is very sensitive and can detect closing and opening in the micro second and possibly even nano second range. So, any switch that is not 100% clean when they make and break can trigger the CDI. For the past year, I have instructed anyone with a points issue to set the point gap in the .003" range. The CDI does not have dwell time like the old Kettering system does. My logic being, if the points don't have to move far, then there is less chance they could bounce or slide together. I have also tossed out the idea of using a switch/points that are NORMALLY CLOSED and open only when you need the spark. The CDI doesn't care which state it is in most of the time, it just needs to change. The WHITE wire is logic HIGH and if it is held in the ground condition and only released when a spark is needed it should  fire the engine reliably. This doesn't mean it won't fire when they close again but it would be after the correct spark timing and should not be a problem. Now that the new Version CDI is finalized I hope to be able to spend some time looking at remedies for the erratic operation of some micro-switches and points. I hope a small value capacitor on both the micro-switch and some points setups might eliminate the erratic firing. On most electronics with mechanical switches there is software that debounces the switch and that includes push button switches. I could program a module similar to the one used to convert our single spark to a buzz coil but that would be over kill. I am always glad to get feed back from anyone and know I have not kept up as well as I should have. It has been a struggle over the past 2-3 years with the CDI because manufactures kept obsoleting parts. With the new version CDI, I am having the transformer wound here in Ohio and I am hand soldering the components on the board so now we have complete control over the manufacturing of the CDI. If anyone has tried the normally closed points set up, I would definitely like to hear from you. I do get email updates when someone posts and now I hope to be able to keep up with what's going on. I hope this sheds some light on how the CDI operates. The reason we don't see this with the hall sensor is because it is not mechanical and by design it is in one of two states, either ON or OFF, nothing in between.
> ...



Why not use tried and true "hardware debounce".
The problem you encounter with a mechanical switch is not "new" or unknown, in fact the solution has been around almost forever.
Below is a  link to "hardware debounce" circuit and if the output logic does not suit your application, simply add an inverter transistor stage, simple.

Look at hardware debounce about half way down the page, operation of it is explained under the circuit diagram.

http://dduino.blogspot.com/2012/03/arduino-button-debouncing.html

Another source for explanation is in this video.


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## editor123 (May 9, 2019)

cfellows said:


> I was doing some troubleshooting yesterday on my plumbing engine (wouldn't start) and I pulled the plug out to see if it was firing. I discovered that the S / S CDI ignition module fires twice, once when the switch closes and again when it opens.  Has anyone else observed that? Just wonder if that's normal operation. I'm using a micro-switch instead of the hall affect transistor...
> 
> Seems like that could potentially be problematic if my ignition is firing at the beginning of the compression stroke, where the switch closes and at the top of the compression stroke when it opens.
> 
> Chuck


You could be getting switch bounce if you are using a microswitch. But I see that Roy has already suggested that.


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## rsholl (May 10, 2019)

bluejets said:


> Why not use tried and true "hardware debounce".
> The problem you encounter with a mechanical switch is not "new" or unknown, in fact the solution has been around almost forever.
> Below is a  link to "hardware debounce" circuit and if the output logic does not suit your application, simply add an inverter transistor stage, simple.
> 
> ...




bluejets,

That does not work on our CDI. The WHITE wire is already logic high and feeding any voltage into it is a NO, NO. Most standard automotive points work well if the gap is kept small, in the range of 3 to 5 thousands of an inch. For reed or micro switches you would have much better luck using a NORMALLY CLOSED type switch. If you already have a standard NORMALLY OPEN type switch, just set it up so it is activated (switch closed) and release it when you want to fire the CDI. Another option would be to add the Buzz Module (which I checked and see I do not have listed but will do that next) to an existing single spark cdi and convert it to a Buzz type CDI. The timing would have to be changed slightly as the buzz module will make the CDI oscillate or buzz as soon as the points close and stop when they open. This should not be a major problem for most engine. If there were enough interest, I could program the little circuit board I use for the buzz module and make it de-bounce noisy switches.


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## bluejets (May 10, 2019)

rsholl said:


> That does not work on our CDI. The WHITE wire is already logic high and feeding any voltage into it is a NO, NO.



You could simply use an open collector to my original suggestion and that would suit your needs.


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## rsholl (May 11, 2019)

bluejets, I agree on using the open collector and that is what our hall sensor is, plus it plugs straight into the cdi with no extra circuitry.


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## bluejets (May 11, 2019)

rsholl said:


> bluejets, I agree on using the open collector and that is what our hall sensor is, plus it plugs straight into the cdi with no extra circuitry.



Yes, I am well aware of what a hall effect is.

Very confusing ...I thought the discussion was about using points.  ...??


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## rsholl (May 19, 2019)

Yes, I think we got off subject a bit. Lets get back to a bare set of points and forget about trying to add additional circuitry to them to de-bounce them. The best thing to do when using automotive type points is to set the gap as minimal as possible (less than .005"). The second option is to make the points cam such that the points are normally closed and open very briefly right at the moment you want the engine to fire. If the points bounce then it shouldn't be an issue as the spark would occur after the initial spark required.


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