Roll Your Own CDI

[impression]

oh thankyou for the Gearnut

I wish it was possibly to determine which type one is before you buy it

 

[GearNut]

All modern automotive coils are a rising field type.

COP or "coil on plug" are the most common.

 

[DuctTapedGoat]

So, what about a television's flyback transformer - would that work?

 

[GearNut]

I have no idea how those are wound. I bet rohmell does though!

 

[DuctTapedGoat]

I pulled one from an RPTV I was in the process of gutting after rohmell made a mention of it, but I need a CDI to be able to test.

I wish I knew how to test it with a multimeter to see if it would work or not.

 

[impression]

I pulled one from an RPTV I was in the process of gutting after rohmell made a mention of it, but I need a CDI to be able to test.

I wish I knew how to test it with a multimeter to see if it would work or not.

:OOO thatnks for the IDEA !!! i have a CRT monitor 19" flat that i'm gutting for parts soon

 

[Greg58]

I hope you have better luck than I did with the flat panel monitor, no parts had a v rating high enough to be used for the cdi.

 

[Ratchetbirds]

Yeah I was wondering about the flat panel montor stuff you guys were mentioning. I didn't take my old dead one apart because I figured it was low voltage throughout, except for the initial power supply. Now a CRT, that would have lotsa higher voltage stuff in it. Check some of your local scrap outfits, if they are like mine they have hundreds of CRT's and would be willing to sell you one for real cheap. Just a thought.

 

[DuctTapedGoat]

That's why I pulled mine from a rear projection TV, it should drive it like nobodies business.

 

[Ratchetbirds]

Like literally light up the world? Or maybe light up my life, you. Sorry, goofy friday today. That sounds right to me, lotsa big zap stuff in there

 

[impression]

well a transformer or a tesla coil should also do the trick.

Need to read up on flyback transformers though.

 

[Ratchetbirds]

I found this on wikipedia about flyback transformers so be sure to read it with a grain of salt but it may help.

Flyback transformer - Wikipedia, the free encyclopedia

Also here is a chart from where I purchased my capacitors from that cross refrences uf, pf, and nf and also has alot of infor for the layman about capacitors but it is a site for restoring antique tube type radios.

http://www.justradios.com/uFnFpF.html

 

[GearNut]

After reading the Wiki on flyback transformers I can tell that they are a rising field type.
The primary winding is wound first with the secondary winding wrapped around it.
Collapsing field coils are wrapped opposite of that.

 

[DuctTapedGoat]

Hey - that's some good news to hear!

 

[rohmell]

Hey Rohmell, would these caps work?


5 pcs Capacitor CBB 630V 105 105J 1uF 1000nF 5% New | eBay

Sorry for the late reply, I was on Holiday, but yes, those caps will work in the CDI project.

 

[ducedave]

Hay rohmell good to see you here- I built me cdi but no fire I think I cooked the scr with the soldering iron pulling out of the downer board just going to replace it as every thing less check out right-as for pics that's depends on kids and their help with pic phones and so often with young ladies good luck! pulling them away from what ever their doing or avoiding doing so I don't know when pics will be posted

 

[ducedave]

I changed out the scr and it runs but I have way to much advance at idle on up what needs to be changed I'm guessing the 18ohm and or the 82ohm resister for a grater ohm?I'll file out the magnets groove and epoxy up the slack-I've started filing and checked it and it's getting better I'll finish in the morning should kick butt-after the timing is right I'll dial the retard if need be at the 2.2uf small cap with a 3.3uf or a 1.1uf
THANK YOU ALL AND A SPECIAL THANKS TO rohmell WHO MADE THIS POSSIBLE!

 

[rohmell]

I am glad to hear that you have gotten your CDI running!

There are so many variables; magnet timing, type of ignition coil being used, etc, that you will have plenty of opportunity to experiment with different values and fine-tune your CDI for maximum performance.
In place of the two fixed resistors, you could try a variable resistor (potentiometer) to make it easy to experiment on the fly.

 

[ducedave]

I am glad to hear that you have gotten your CDI running!

There are so many variables; magnet timing, type of ignition coil being used, etc, that you will have plenty of opportunity to experiment with different values and fine-tune your CDI for maximum performance.
In place of the two fixed resistors, you could try a variable resistor (potentiometer) to make it easy to experiment on the fly.

Dude you've been good to share your wisdom-I'm going to find the timing sweat-spot by moving the magnet then tune the cdi's curve from that point-hopefully I'll just have to fine tune one end of the curve the retard- 1 question though to get more retard would I go < or > the 2.2uf. small cap on the retard side or is it better to change out the 560ohm. resister < or > for now back to the magnet for me install and test ride time.
it's getting closer,just a Little at a time.

 

[Cagiva4ever]

Hi ! people

Regarding these various cdi plans/files from web, has any1 happen to have the "Siliconchip" web sites mentioned magazine/files from "Programmable Ignition System from March, April & May 2007" ?

Silicon Chip Online - Replacement CDI Module For Small Petrol Motors

Regarding that cdi above, is there other upgrades to cdi designs than Thermistor, Potentiometer Resistor and Resistors for SCR malfunction back-up.. ?

any1 happen to know that is there many options on integrated/build-in timing light/strobo designs ? ive seen strobo on a hobby RC engine cdi instructions found from web.

im so intrested about all these Gizmos on cdi designs...

ive been reading so much during past 1 month but i havent found yet answers to those mentioned guestions.

bye
m