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Old 03-26-2017, 12:47 PM   #1
Chuck Sea/Tac
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Default Coil tester diagram

Is there a link to a simple diagram for a coil tester?
I have a clip soldered to a spark plug, with a pigtail coming off. I hooked it to the neg of battery , and pigtail to minus of coil. Hi tension wire to plug, and then sparked the positive side of coil to positive terminal of battery to simulate points.i get coil spark, but no plug hi tension spark. Have I got this correct? I also tried several different coils, with the same results.
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Old 03-26-2017, 01:37 PM   #2
Kevin in NJ
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Default Re: Coil tester diagram

Here is a link to Tom W. simple and effective coil tester:

Coil Tester

A coil tester needs to have a variable gap you can adjust. It also must have a heat mode to cook up the coil. Often a coil tests good cold and fails horribly when warm.

You can also check condensers but just buy the A&L burnout proof item and not worry about it.
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Old 03-26-2017, 01:38 PM   #3
Drive Shaft Dave
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Default Re: Coil tester diagram

I don't see a capacitor in your circuit. You need one or no secondary spark.
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Old 03-26-2017, 02:34 PM   #4
Chuck Sea/Tac
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Default Re: Coil tester diagram

Ok ,that's what's missing. I didn't realize I needed storage to spark when the circuit collapsed. I thought the condenser was more to protect the points from burning.
On the same thought line, why doesn't my electronic ignition need a condenser?
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Old 03-26-2017, 03:15 PM   #5
Tom Endy
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Default Re: Coil tester diagram

Bratton's sell a coil tester that can be used on the car. Part number 17150. it has a gap that can be expanded and you can see if a strong spark can breach the gap. They also sell a tester that will determine the polarity of the coil as it is wired to the car. Part number 17140. I have had both for years and they are very handy tools.

When I first obtained the polarity tester I used it to check every club member's car that was present at a club event. About half of them had the polarity reversed.

The only thing the coil tester will not do is tell you if the coil will fail at very high temperature. A coil will expand at a high temp under the hood. It can cause the high voltage windings to short out. When the car and the coil cool down the short disappears.

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Old 03-26-2017, 04:11 PM   #6
Tom Wesenberg
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Default Re: Coil tester diagram

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Yes, just connect a condenser to the coil primary terminals and you should have good spark. The condenser does protect the points from arcing and burning, but it is also needed to absorb the higher voltage and bounce it back through the coil to give the really high voltage spark.
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Old 03-26-2017, 07:11 PM   #7
updraught
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Default Re: Coil tester diagram

Quote:
Originally Posted by Chuck Sea/Tac View Post
Ok ,that's what's missing. I didn't realize I needed storage to spark when the circuit collapsed. I thought the condenser was more to protect the points from burning.
On the same thought line, why doesn't my electronic ignition need a condenser?

Good question. A Google of "
why doesn't my electronic ignition need a condenser?" brings up
http://www.breakerless.com/igntionfacts.htm

".... the coil current can be switched off much faster. This results in a faster collapse of the flux, creating a higher secondary voltage. Additionally, since this thing is a solid chunk of silicon, there is no opportunity for creating an arc (or the erosion that results from it)."
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Old 03-27-2017, 10:20 AM   #8
Will N
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Default Re: Coil tester diagram

Quote:
Originally Posted by updraught View Post

Good question. A Google of "
why doesn't my electronic ignition need a condenser?" brings up
http://www.breakerless.com/igntionfacts.htm

".... the coil current can be switched off much faster. This results in a faster collapse of the flux, creating a higher secondary voltage. Additionally, since this thing is a solid chunk of silicon, there is no opportunity for creating an arc (or the erosion that results from it)."

I think another reason is that in a 12 volt system with points, there is usually a resistor that drops the voltage in the primary circuit because 12 volts going through the points will burn them out quickly. Without the points to worry about, you don't need the resistor to lower the voltage in the primary, and with the higher voltage in the coil, you don't need the recharging of the coil that the capacitor provides in a points system.
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Old 03-27-2017, 12:01 PM   #9
johnbuckley
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Default Re: Coil tester diagram

Quote:
Originally Posted by Tom Endy View Post
When I first obtained the polarity tester I used it to check every club member's car that was present at a club event. About half of them had the polarity reversed. Tom Endy
.... and tell me Tom , did putting the polarity right make any noticeable difference?
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