2 stroke - Off the shelf Ignition?

[V22]

I am thinking about purchasing a simple ignition system for a Jan Ridders 2 Stroke "Debbie" engine I am building. The system I am looking at is the Rcexl Single Cylinder CDI Ignition. Is there any reason why I should steer clear of this system? It looks to do the coil and firing work, leaving me with only having to mount a magnet and hall sensor?

Am I missing something here or is this a good way forward?

 

[Swifty]

That's the same as I have in my latest 4 stroke motor. I am very impressed with the system, of course, with a 4 stroke I have a wasted spark on the exhaust stroke.

Paul.

 

[naijin]

I am thinking about purchasing a simple ignition system for a Jan Ridders 2 Stroke "Debbie" engine I am building. The system I am looking at is the Rcexl Single Cylinder CDI Ignition. Is there any reason why I should steer clear of this system? It looks to do the coil and firing work, leaving me with only having to mount a magnet and hall sensor?

Am I missing something here or is this a good way forward?

Best thing that I have bought, I have it running my 4 cycle home made engine ( for the last two years... ) and it never missed a beat, well worth the money

Regards

Nick

 

[Jasonb]

You may want to take a look at the ignition that Jan posted about here recently

http://ridders.nu/Webpaginas/pagina_blokker_vonkcircuit/blokker_crcuit_frameset.htm

Also worth considering the ignitions from S/S, I tend to use them as they don't have the auto advance that the Rcexl ones do and as they use a separate ground wire you don't have that big ugly braided lead and metal plug cap.

http://cncengines.com/ic.html

 

[V22]

Thanks Paul and Nick for the vote of confidence in the rcexl system.

You may want to take a look at the ignition that Jan posted about here recently

http://ridders.nu/Webpaginas/pagina_blokker_vonkcircuit/blokker_crcuit_frameset.htm

Also worth considering the ignitions from S/S, I tend to use them as they don't have the auto advance that the Rcexl ones do and as they use a separate ground wire you don't have that big ugly braided lead and metal plug cap.

I really wanted to avoid disassembling, soldering and reassembling circuits. My interest at this point is in machining and not so much the electronics side.

What issues will the auto advance likely cause?

 

[Jasonb]

Should not be such a problem on a 2-stroke as you are giving it the signal off the crankshaft but these units have their timing charicteristics better suited to higher speed engines and not the slow reving 600-1500 you are likely to want on that engine.

Basically if you set the spark to say 5degrees before TDC the electronics will start altering that thinking the engine is running slow.

 

[tornitore45]

of course, with a 4 stroke I have a wasted spark on the exhaust stroke.

Swifty, I believe that is not a consequence of 4 strokes versus 2 strokes.

I suspect you have the magnet on the crankshaft, if you had the magnet on the camshaft it will give one spark every 2 turns.

It makes no difference unless the RPM is so high to miss.

I have a similar arrangement on a Boxer engine, one fire per revolution hitting one cylinder in compression and one wasted during exhaust on the opposite cylinder.

 

[Swifty]

Mauro, thanks for the input, I actually have 2 magnets on the camshaft so the ignition receives a signal for the correct RPM. As the ignition adjusts itself for spark advance as it gets faster, it's important to have the correct RPM. If the magnet was on the crankshaft I would still get a spark on the exhaust stroke. I initially only had one magnet on the camshaft, until another member pointed out the problems. If you are using point and coil ignition there is no problem with using one magnet.

Paul.