6 Volt CDI units?

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Geordie Greenwood
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Re: 6 Volt CDI units?

#16 Post by Geordie Greenwood »

It is basically plug and play. The installation instructions are easy to follow. The coil, distributor etc. do not need to be changed, but you do need to use a rotor that does not have a built in resistor, or bypass the resistor.

If you follow Jack's link above to capacitordischargeignition you should find all the information you need.

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Fred Winterburn
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Re: 6 Volt CDI units?

#17 Post by Fred Winterburn »

Folks, I spent the money and joined the forum. I do not own a Porsche of any kind, but I do make a 6V CDI. This is a real CDI, not a transistor-switch inductive system that typically works more poorly than the already challenged 6V Kettering system. I expect to have another batch built and ready by January. The demand for 6V units is so small, that I will only build what I have orders placed for. If anyone is interested and doesn't mind waiting, please pre-order at winterburnignition@gmail.com I do not need a down payment, just an expression of interest in receiving a unit when they become available. Also see: www.capacitordischargeignition.com Thanks Fred Winterburn

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David Jones
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Re: 6 Volt CDI units?

#18 Post by David Jones »

Fred, may I ask how your CDI compares to the no longer available 6 volt Permatune CDI? What is the technical difference that makes yours able to operate at such low voltage versus the higher threshold voltage of the Permatune. I have not had any issues with my Permatune but I always keep my battery on a maintainer.
Do you know how much difference there is between spark intensity of the two units?
If I had known I would live this long I would have pushed the envelope a little harder.
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Alan Hall
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Re: 6 Volt CDI units?

#19 Post by Alan Hall »

Or the old Delta Mark 10 6volt CDI units which were great when you started burning oil but couldn't afford a engine rebuild. I think I still have a couple of these in a box somewhere.

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Re: 6 Volt CDI units?

#20 Post by Fred Winterburn »

David,
I have never tested a Permatune 6V unit. I have tested an old Blue 12V unit and they would trigger and produce a starting spark down to 6V which is quite good. Those units have a weak spark with a strange positive potential spark for the first part of the spark, followed by a negative strike immediately afterwards. The rpm potential with the NOS unit I bought would be sufficient for a 6 cylinder car, but would not maintain the required spark rate for an 8 cylinder. I know nothing about the later Permatune units. The original Blue 12V unit is a very close representation of the Theodor Sturm patent that was filed just a few days after my father filed his CDI patent.
The last batch of 6V units I built were all capable of producing a strong starting spark down to 3V. I advertise 3.5 volts, but every one so far has been better than that. If I hadn't made the units polarity insensitive (diode voltage drops), they would be able to produce a strong spark to as low as 2.1V. I do not know why the 6V Permatune won't function to as low as at least 4V (how low do they go?). The original Hyland that my father designed would function down to 4V at that was considered satisfactory even in very cold weather with reduced battery voltage and more amps drawn to turn over a cold engine. It used a different power supply design than the one I developed for this unit. 4V should be satisfactory for most 6V applications, but I wanted some extra margin. Fred

David Jones wrote:Fred, may I ask how your CDI compares to the no longer available 6 volt Permatune CDI? What is the technical difference that makes yours able to operate at such low voltage versus the higher threshold voltage of the Permatune. I have not had any issues with my Permatune but I always keep my battery on a maintainer.
Do you know how much difference there is between spark intensity of the two units?

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Bill Sargent
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Re: 6 Volt CDI units?

#21 Post by Bill Sargent »

Jack - did you get the Winterburn CDI units up and running with your motor? Be interested to hear your experiences.
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Ron LaDow
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Re: 6 Volt CDI units?

#22 Post by Ron LaDow »

Fred,
I'm in no way opposed to improving the 616 engines, especially if the improvements are 'non-invasive' as it seems your device is.
But I'm not sure what improvement is offered here. Pretty sure I'm not alone in wondering why some parts should be replaced either, especially since I'm not yet clear on what gets replaced and what is gained by doing so.
Specifically, why would anyone change what parts? What improvement are they going to see?
BTW, by convention, the vendors to the Registry post an 'ACHTUNG!' note here regarding new stuff, and then expand on it over in the Vendor notices here: viewforum.php?f=19
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Re: 6 Volt CDI units?

#23 Post by Fred Winterburn »

Ron, Thanks for the warning on advertising within the forum. The system is completely non-invasive in that you use all of the existing ignition components. With this system, points, coils, and spark plugs last longer and the spark is far superior to the Kettering system and considerably superior to a Pertronix 1 conversion. The inherent voltage drop of the pertronix makes it a really poor choice with 6V systems. The only part that won't last as long is the resistor in the Bosch rotor. Those resistors are weak and prone to failure at the best of times but will be really short lived with the CDI. The only way to be convinced at how well this CDI works, is to try one. Results vary, but typically 6V cars see the most benefit and cars with hemispherical combustion chambers. Fred
Ron LaDow wrote:Fred,
I'm in no way opposed to improving the 616 engines, especially if the improvements are 'non-invasive' as it seems your device is.
But I'm not sure what improvement is offered here. Pretty sure I'm not alone in wondering why some parts should be replaced either, especially since I'm not yet clear on what gets replaced and what is gained by doing so.
Specifically, why would anyone change what parts? What improvement are they going to see?
BTW, by convention, the vendors to the Registry post an 'ACHTUNG!' note here regarding new stuff, and then expand on it over in the Vendor notices here: viewforum.php?f=19

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Re: 6 Volt CDI units?

#24 Post by Al Zim »

I have a 1976 BMW motorcycle that needed twin plugs to start easier and not continually ping on acceleration above 4000 RPM. As part of the solution I used the Onan ignition coil which has two primary leads and is epoxy filled and a 3 pin 911 cd unit. If you coupled this with a AGM battery that is used for emergency lighting (also starts the BMW) cost about $100.00 with an off/on switch this would solve your situation with a minimum of cost and could easily be put back to stock. al zim
Last edited by Al Zim on Wed Jan 03, 2018 3:04 pm, edited 2 times in total.
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Charles H Jacobus
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Re: 6 Volt CDI units?

#25 Post by Charles H Jacobus »

Fred:
Does that mean you need to use another rotor, or is there one?

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Re: 6 Volt CDI units?

#26 Post by Fred Winterburn »

What I used to do with Volvos, was grind the resistor out and solder in some #14 wire. I believe that aircooled.net also sells rotors sans resistor for CDI applications. Fred
Charles H Jacobus wrote:Fred:
Does that mean you need to use another rotor, or is there one?

ChuckJ

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Re: 6 Volt CDI units?

#27 Post by Charles H Jacobus »

If you don't have a resistor do you get radio noise interference?

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Re: 6 Volt CDI units?

#28 Post by Fred Winterburn »

The ignition noise is lower with the CDI because the ground return path to the coil is not back through the ignition switch. I have found no difference with or without a resistor rotor. The inherent spark gap built into every distributor creates enough noise on its own. If there is any noticeable noise, spiral wound suppression wires (I like Taylor brand) and/or well built resistor spark plugs can be used with copper conductor plug leads. As long as the total resistance is less than 10 thousand ohms to each spark plug, the CD ignition will have plenty of energy. Champion resistor plugs are weak, NGK strong. On my Volvo and Morgan, I use 5 kohm resistor plug caps normally used for off-road equipment. Those resistors are bulletproof and designed to withstand CD ignitions.
Charles H Jacobus wrote:If you don't have a resistor do you get radio noise interference?

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Re: 6 Volt CDI units?

#29 Post by Charles H Jacobus »

Thank you Fred.

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Re: 6 Volt CDI units?

#30 Post by Jack Walter »

Bill Sargent wrote:Jack - did you get the Winterburn CDI units up and running with your motor? Be interested to hear your experiences.
I'm working on it...too many projects and other distractions. My mother had some health problems and we had to find her a new assisted living facility - that along with my busted arm made for some difficulty finding time to work on the Porsche.
Back at it today after getting some other things out of the way.

I've got the Wimterburn units mounted and the wiring harness run to the back of the engine compartment.
I decided to mount the two CDI units inside the passenger compartment under the back deck that Dean installed in place of the jump seats. There isn't a lot of spare room in a 4-cam engine room.

I did take my two distributors over to a friend of mines shop where we went through both distributors on his Sun machine and got them matched up as well as we could.
I had to hone the distributor bodies to insert the new capacitors as they were .003" bigger in diameter than the cavity in the distributor. Removing the old ones was pretty fun too.

I tested my two coils today and found that one of them has a higher than recommended secondary resistance so I probably should try to find one that is within spec.

I'm going to the PCA Porsche swap meet tomorrow at Ray Morgan's shop and maybe I'll find a good 6 V Bosch blue coil there.

I have to drive my mother in law down to Florida next week but I hope to fire it up and try it out next weekend. I've been following Fred's experiment with the ceramic capacitor as well.
I'll let you guys know how it all works once i crank it up in a week or so.
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