RE: Scratch Built Ignition???
 

A big thank you to everyone who has helped out!!! Im sorry that I have not got back sooner. Im very busy trying to go to school 3 nights a week work 48 hours and spend time with my wife on the weekends. So I have not been able to spend much time with this project. I am also trying to build a 33% extra 230. . I have a rather large engine for it 50-60cc to put this system on!!!I give yall a heads up on my system in a few!!Thanks alot. Matthew

RE: Scratch Built Ignition???
 

I have a small spark coil that I use in my CDI system. It is 5/8" Dia. by 1 3/8" Long with 3" leads. The specs for the coil are 400 Vdc in and 26 KV out, these are maximum values, minimum input voltage is 200 Vdc for the smaller weed trimmer type engines (31cc and below). If anyone is interested in purchasing a coil I can ship to most 48 states and Canada for $14.95 which includes First Class Postage.

I am including an image provided it uploads.
[img][/img]

Thanks,
Roy Sholl

RE: Scratch Built Ignition???
 

You will need to go to my gallery to view the coil.

Thanks

RE: Scratch Built Ignition???
 

Where is this Gallery?

RE: Scratch Built Ignition???
 

Where does the High Voltage lead go ???
I'm interested....

"Where is this Gallery?"

Look at the bottom of the message box..... ;)

[:-]

RE: Scratch Built Ignition???
 

Thanks for the help guys. I tried to upload a picture in my message but it did not work, I was able to upload one to my gallery here at RCU. Jim is right on, the gallery icon is at the bottom left of MY message block.

The brown wire is where the spark plug wire gets attached and the red and blue wires are for the 400 Vdc. The blue wire is + and the red wire goes to ground.

I'm not sure what I'm doing wrong but I can not upload a picture into my message.

Roy

OK now we have pictures!!!!!!!! Computers- aren't they wonderful!!!!!!!!!!!!!!

RE: Scratch Built Ignition???
 

please e-mail me your order/payment/shipping info....

[:-]

RE: Scratch Built Ignition???
 

I am selling a PIC controlled CDI unit for $65.00 plus $4.95 for shipping, handling, and insurance via USPS first class mail for a total of $69.95. Foreign orders will run more.

The unit is a PIC/CDI module, a wired Hall sensor, and rare earth magnet. You supply the spark coil, battery pack, switch harness, project box, and plug lead wire. You can learn more details at http://home.earthlink.net/~marlowedc/CDI

Payment can be through PayPal (fastest way), money order or personal check. If you are interested please send me a private message.

RE: Scratch Built Ignition???
 

Marlowe,

Good explanation on your webpage.

Can you supply a graph showing the automatic advance in degrees relative to RPM, please?

Thanks,

Dan Clarke

RE: Scratch Built Ignition???
 

here it is:

EIS Timing Curve


After doing research on engine timing curves plus conducting many engine runs, I came up with the following timing curve.
This timing curve was then translated into timing parameters and the algorithm was programmed into the PIC chip. So when the PIC measures that the engine is ticking over at 1800 RPM, it delays the spark firing to occur at TDC (zero degrees). Likewise at 6,800 RPM it adjusts the spark advance to 25 degrees BTDC. Above 8,000 RPM the curve flattens to 32 degrees.

RE: Scratch Built Ignition???
 

I have done alot of ignition work on race two stroke engines
Jetskis as my name would suggest

At the top end of the curve about 6000 rpm on wards you need to turn your timing back
this will heat up your tuned chamber (assuming you are using a tuned pipe) and increase the speed of the sonic wave
which returns a pulse back to your exhaust port sooner and allows the pipe to keep reving on
this is worth a lot in overrev for your engine
try it you will be suprised
Here is the curve i use on my 800cc two stroke

RE: Scratch Built Ignition???
 

Whoa, that is so totally different than the curve I'm using (others are using it on their airplane engines too). What is the red line on the upper end of the chart?

With my software I could program such a curve but we are not running high performance, tuned pipe. Thanks for sharing this with me.

RE: Scratch Built Ignition???
 

Ford did the same thing on their Hi performance engines.

At the highest revs, 7500-8000rpm I'm guessing, the advance was retarded slightly for more power.
Their distributors had 2 vacume lines running to it.

What's old is new again.

RE: Scratch Built Ignition???
 

The ignition i am using can run two curves in it
the red line is the other curve but i am not using it so it just on it default setting

It one they use on alot of (80-125) mx bikes

RE: Scratch Built Ignition???
 

Marlowe I am just starting work on a homie 25
And i am looking to go wild on it as its going in a hovercraft which is not following any other design than my own
I am looking to get an ignition for the engine if you can help me out with an ignition i will post results etc up here and maybe we can all learn something regarding the curves
i have a crude form of dyno in my test equipment that measure time between a certain rpm to a time between another rpm of which i can set the start and finish rpm, also i will be using egt measurement so you know its going to be right.

I will be using a tuned pipe on this engine so i am not sure how that will effect the people that don't use one.

the reason they retard the timing up top is because the hotter a pipe the faster the sonic wave travels
as the rpm comes up a engine need a faster return on the pulse to keep it scavenging effectively
With the retarded timing the exhaust heats up and makes for a quicker return on sonic wave helping the engine to rev on
However when it get to the point that the pipe will no longer return the wave back fast enough we shove some timing back into the engine to help pick up a wee bit more power
putting the timing back in is worth about 200rpm (1.5 mile an hour where i come from)
Retarding it top to heat the pipe up is worth massive gains and no body would consider not doing it.
Here is my hovercraft it has had some beatings in its life the poor thing.
I made the mistake of putting the rudders to far away from the propeller but hey it was a home designed model

RE: Scratch Built Ignition???
 

I have an msd ignition system that i can program but it weighs about 2kg but it will let me sort the curve out
and then i can give you a copy of the curve.
Interested ??

RE: Scratch Built Ignition???
 

Great thread, its helping me a lot.
I have a Moki branded electronic ignition came with a 22cc gas off unknown origin, I am not sure but I think it is cdi type, I was told that it has an auto advance curve.
I am however still confused as to which way round these units adjust the timing. Surely all the electronics can do is retard the timing not advance it, this being the case I assume I set the static timing at the fully advanced value and the electronics then retard it as needed(the first spark however would be at full advance) ?????????????/
Im sure Ive missed something obvious here and could do with some confirmation on this before I start the engine,......... thanks for all the great info

RE: Scratch Built Ignition???
 

normally an ignition gets it pulse at about 52 degrees advance so there fore its all retard from then on in
even at full advance that you see its still a 26 degree retard for the ignition box
i hope that makes sense

RE: Scratch Built Ignition???
 

Yea thanks, that does make sense, but is the low end timing pre set retarded?, or does it need to see two magnet passes to set the appropriate value?
I ask this so I can set the static timing correctly with a degree wheel

RE: Scratch Built Ignition???
 

well i havent done a r/c engine before so its based on my other two stroke experience which is quite alot

normally i just fire up the ignition and take plug out and rotate the engine past the pickup and you will get it to fire the plug
have a look at your degree wheel then and you get your static reading
its an easier way of doing it than trying to set it up with out ignition on

RE: Scratch Built Ignition???
 

Thx waxhead, I know the procedure, just not sure on actual figure (degrees), I should set it

RE: Scratch Built Ignition???
 

try looking here for an ignition as well

http://www.msdpowersports.com/2004_goped.html

RE: Scratch Built Ignition???
 

What?
'1.25”H x 2.25”W x 5.75”L and weighs only 15 oz.'

It will almost double the weight of the engine[>:]

RysiuM

RE: Scratch Built Ignition???
 

nice big long thread...especially when you read the whole thing.Now i have a few questions,any way to set up an electronic ignition that runs off a magneto or something similar?(trying to eliminate battery) And have any off you converted a motor to use as a marine engine with electronic ignition?I'm working on converting a husqvarna 39cc for use in a nice sized fiberglass hull.Thanx :)

RE: Scratch Built Ignition???
 

opps ok so its heavy( need more power then haha)
looks cool though
was thinking more for my hovercraft i am building not so worried about weight as you guys