Ignition circuit help

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In addition, a fouled plug (shorted) would take the hit every time and the engine would stop instead of running on one cylinder.

Sage
 
I have heard the same thing Sage has presented. I have to believe that if the Y cable worked like you say, there would be engines out there with Y cables on them. Putting the plugs in series forces the spark in the compressed cylinder
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What do you think your coil is doing??????????????? it does not look lyke a why but you can't judge Santa Claus because of it's suit

In addition, a fouled plug (shorted) would take the hit every time and the engine would stop instead of running on one cylinder.
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your write with this quote you should see what happen when a coil like Steve goes wild backfire all over the place

It sound's like off topic .............................. simply check glow plug operation on a twin.... it doesn't shut off
simply nothing to burn :)
 
I hope you realize that this is the type of plugs I was talking about

glow plugs.JPG
 
I have been looking at coils for plan E. There are dual coils that are 1.5 to 5 ohm and some of them say "for points" Should I just eat this coil and get a 3 or 4 ohm coil? That might solve the entire problem other than the mounting of the coil. I could try this circuit or maybe build the circuit Les posted and see what happens. They are about 55 bucks. Seems reasonable.
 
I think you already proved that the circuit you have will drive a coil that is "normal" so there seems no need to re-build what you have as a driver at least to get you going. If I remember correctly Les' circuit was not significantly different, just possibly more fault tolerant. None of the circuits are going to blow a coil meant for 12v (unless you leave it on for a long time).
Where are you looking up the coils? Seems reasonable that if it says "for points" then it's a more conventional coil and it might work.
Are they available from places like Autozone etc?
You could buy, try and return if unsuccessful. (Check the return policy though). Not sure about what resistance would be good. Two ohms would be reasonable. The circuit as-is should drive 6 amps ok.

Maybe give Lakc's CDI unit a try on the bench. That'll tell you more about the coil you have.

(Yah I know not much help)

Sage
 
stevehuckss396 said:
I have been looking at coils for plan E. There are dual coils that are 1.5 to 5 ohm and some of them say "for points" Should I just eat this coil and get a 3 or 4 ohm coil? That might solve the entire problem other than the mounting of the coil. I could try this circuit or maybe build the circuit Les posted and see what happens. They are about 55 bucks. Seems reasonable.
Click to expand...


yes :( yes ;) yes ;)
and the rest of it, put in a BIG book of experience or grey hair:hDe:
 
Always good to be looking ahead. You have nothing to lose. Buy the coil if you think it will work. You build enough engines that you'll use what's left over at a later date.

Sage
 
Steve,
If you get down as far as plan G, take a look at the CDI unit from CNCengines that you have used on another engine in the past. The early ones from them had both ends of the high voltage winding available. A couple of years ago they grounded one of them internally in the coil so only 3 terminals are available on the coil instead of the 4 that were available on the early ones.

If yours has all 4 terminals available on the coil, just lift the ground connection that is on one end of the high voltage winding and run it to your second plug. I looked at my coil and both ends are insulated equally so lifting the second end above ground will cause no problems.

Last night I modified one on one of my single cylinder engines and set up a dummy second spark plug with an adjustable gap to check it out. Engine runs same as before as I varied the adjustable gap from zero (shorted) up to 1/4 inch which was the maximum I could set the adjustable gap to. Nice lively second spark in the dummy plug gap all the time.

The last ignitions I got from Roy all had the 3 terminal coils. That was about 1-1/2 years ago. I presume the current crop also does.I was going to check with Roy, but he is currently having problems with Google thinking his website is infected with some malware. All his internal checks say it is OK but Google persists and won't let Firefox browsers (and others) onto his site. I am not going to bug his about my little problems until he gets his problems resolved.

I, as I suspect, the current coils only have 3 terminal, he may have some of the old coils there as replacements as he did sell them on his site in the past. Only a few minute job to change out a coil if he does. Of course if your old system has one of the 4 terminal coils you could use it and replace it with a new system.
Gail
 
If you want to get together tomorrow afternoon just drop me a line. I work till 5ish at 12/Haggerty
 
No problem, whenever you get a chance.
I must be getting old, I remember Autorama being on Daytona weekend.
 
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