coil questions

here it is i hope......
 

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Using the second waveform as a example the coil current would turn on as the timer makes the ground circuit and the current would ramp upward to approx 4 amps (12 volt battery) in approx 1.5 mile sec. The firing point is the coil discharge by dropping straight downward with diminishing ocillations showing proper discharge with even pattern and then the start up of the next firing cycle.
I will get some captures later from a running engine to show timer operation etc....
 
I do however find it almost impossible to adjust the coil to have only a single spark however.


The aim in using a HCCT is to adjust the coil so that each spark is a single, clean spark. The second point on the underside of the point set is sort of a damper that needs to be regulated to achieve this.

The coil will buzz creating multiple sparks as long as the citcuit is closed but when not adjusted properly each spark is not clean & often you can see many double & weaker sparks in place of a regulated series of individual well defined sparks when the HCCT is rotated.
 
The double firing that I am speaking about is when the ******** bounces twice or more on the same energy pulse not when two or more of the 16 pulses fall within the firing cycle. The firing cycle being when the roller is in contact with one of the 4 points in the timer.
 
Jack, we were both posting at the same time. Ron,s videos he made in conjunction with the MTFCA are very good in showing how to get the points not to double fire. I have come to the conclusion, it's a lot of work but worth it.
 
GOOD POST GUYS !!!

I never even dreamed a T could be adjusted to have a single spark per cylinder. I will get some scope pics as time goes on and spend a sat or so looking at this one for sure.
I assume this would be even harder to do using the magneto as the voltage rises quite a bit ?????
 
Voltage doesn't matter, the coil should be set to fire a single spark at 1.3 amps. With 12 volts the coil will ramp up quicker to the 1.3 setting. This is why a T will run better on 12 volts over 6 is that with a quicker ramp time, the timing is slightly advanced.
 


The wave pattern previously posted demonstrates what we are describing in a "double spark" The first impulse is a little weak, the next two are strong & even - there should be 16 of these per revolution of the flywheel, the last one is about half intensity and a double spark.

The multiple sparks seem to be created when the points rebound too rapidly - the rivett on the cushon spring needs to be adjusted to act as a shock absorber so the points make & break smoothly when triggered to vibrate.

I would inmagine the result is much the same as if you put 8 different spark plugs, all with different gaps, in your modern engine. The engine would run & probably do a job but it would run noticeably better if all plugs (and sparks produced) were exactly the same.
 
OK, is this double sparking something not to be concerned with if running on 12v battery? IE, only does it on mag?
 
Double sparking will happen whether on mag or batt and needs to be adjusted correctly to prevent it. There is someone in your area with a HCCT or strobospark or you can send them to someone who does. What area are you from?
 
Had the chance to discuss some of this at the Speedster planning meeting held this weekend at Potters Piston Parlor in Bismark Illinois.

The 20 or so T guys threw some more fuel on the fire i guess.

.The number of sparks between comutator segments would be deternined by the type of timer the engine was running on.

.The magneto sends out a a/c voltage making the polarity switch every other pole as well....not really a problem but something else to think about.

. We ran a T engine on a dyno and changed the cam timing but didnt mess with the spark timing of the coils etc. Thats coming up next and there was lots of discussion .
 
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