Well I called friend, an electronic technician, and he explained step uptransformers. Basically the primary windings are going to be a certain amount of copper windings surrounded by a secondary winding field which has double, triple or hundreds more copper windings depending on application. When current is enduced into the primary windings it creates a magnetic field which enduces a current into the secondary windings which due to the multiplied number of windings "steps up" the voltage. Thus when I reversed the polarity on my coil I had 40,000 windings feeding current to lets say 100 windings and since it past their point of resistance that energy was trasnfered into heat, just like the filament in a light bulb thus the reason my coil cooked/ boiled and blew up.

Sound about right?

 

Cali, short form answer is NO....sorry but I am very tired tonight, and can't explain it all now....later...

maybe someone else can....

GENE

 

:skep:

 

It sounds like you've got it! Don't you hate crap like that? There have been a few times I've hooked something up bassackwards and have been totally clueless as to why the d@mn circuit didn't work. The lesson... Voltometer... and check what you're doin all the time. :lol:

 

In order to feed 40,000 to 100 you would have had to connect the 12 volts to the center terminal of the coil. the primary (100 windings)of the coil is connected to the small terminals with nuts the secondary (40,000 windings) terminals are the center (high voltage wire) and one of the small terminals (can't remember which one + or -). So you would have to be very inventive to hook up the coil backwards.

if interested I can see if my scanner will work and scan the theory of coils/ignition for you.

Steve

:steering:

 

Yes would love to read about it.

:yesnod:

 

David,

sounds like :bs

If you reversed the connection it would not blow anything up...however you hooked the coil directly up to a battery without resistance wire and that would cause the coil to overheat. The coil is only connected directly to the battery while cranking because the voltage is low due to the starter drain. Once engine running the resistance wire comes into play and limits the voltage/current in the coil primary.

The vette should have a special insulated resitance wire to the coil for this purpose.

Other electronics savvy folks might like to chime in.

Good luck,
Joe

 

Joe your absolutely right but in my infinite wisdom I bypassed the resister to see if the coil worked then was going to check the resister. Well I proved my theory and at the cost of a $70 coil.


:withstupid: :withstupid: :withstupid:

 

:D More to it than that but the coil does have two windings with a turns ratio of about 400 to one. But with just 12V initial that works out to only about 4,800V on secondary. Now what turns it into 50,000V (on a good coil) is how fast the primary winding current stops or changes direction and all the magnetic lines of force developed in the primary crossing the secondary windings rapidly collapse to produce current flow to the shortest path to ground – the spark plug gap. This happens when the points open up or for an solid state ignition the reluctor opens the primary coil current path and the distributor rotor is pointing at the correct plug. Kinda like the energy built up in primary windings now jumps into secondary windings and out the spark plug - faster than G. Bush can take overtime pay away.
Now I do not know if you really had hooked up your coil incorrectly but the older “stock” coils cannot handle a full 12V for very long. Only for startup is a full 12V is applied to coil from a starter solenoid wire (yellow?) to the pos (+) side of coil. This wire bypasses the normal resistor wire from the ignition switch, which drops coil voltage a bit to reduce primary current and save the coil. Sometimes a “ballast resistor” was installed/used in line with ignition wire the coil +/primary. How much voltage is normal? Sorry, I never measured this. Now there are coils that can handle full 12V all day (HEI) but you need to do the research here.
Next time for the + pos side of coil connect the starter and ignition switch wires (unless your using a electronic box which you will need to follow their instructions) and the coil negative side should go to the distributor – which controls its path to ground. You can verify proper polarity with a long pencil lead between sparkplug and ground with engine running. Sparks need to fly towards ground but please use insulated pliers to hold the pencil. :thumbs:

 

Hey,

not too fast, the coil might have still been faulty, perhaps a secondary winding fault....you'll find out when you get a new one!

Joe

 

When we replaced the coil in my wife's Mustang, we found out that it had been hooked up backwards for thousands of miles. I'm sure this shortened the life of the coil, but other than that, we had no way of knowing that it had been hooked up backwards.

 

I Re-Coil at such Re-Volting problems! I guess it's just the way I'm wired.

Chuck

 

I don't think by-passing the resistor would blow the coil - resistors are used mainly to reduce current jumping across the points and to increase their life. At least that's the way I thought it worked...


[Modified by Frank75, 4:14 PM 12/3/2003]

 

cardo0 het imporatant point I have 2 white wires both producing 12V with ignition on which are going to the input of the ballast and one red wires going from ballast to pos of coil. It was like that when I got the car and it ran, not very well but it started right up with a bit of a miss. I marked on the ceramic ballast, 2 white wires in and one red wire out to coil. Is there a slight chance one of those white wires is the starter wire your refering to and should be runniong to ballast outlet to coil for a full 12V versus the way it is now? If so how did the car start when I fist got it?

David

 

Hey Dave, I just pulled my unilite distributor off the shelf and noticed something I hadnt told you about when I offered it too you... It is a tach drive allright, but it is also mechanical advance.
Let me know what ya wanna do buddy....
I am going to go check out the possibility of having a unilite conversion
kit for your existing unit.. :steering: :auto:

 

Steve can i do as well with mechanical advance only??????? i'm willing to try anyway what you think? hey it may not be the distributer at all.

From Cardo0
________________________________________ _____________________
Now I do not know if you really had hooked up your coil incorrectly but the older “stock” coils cannot handle a full 12V for very long. Only for startup is a full 12V is applied to coil from a starter solenoid wire (yellow?) to the pos (+) side of coil. This wire bypasses the normal resistor wire from the ignition switch, which drops coil voltage a bit to reduce primary current and save the coil. Sometimes a “ballast resistor” was installed/used in line with ignition wire the coil +/primary. How much voltage is normal? Sorry, I never measured this. Now there are coils that can handle full 12V all day (HEI) but you need to do the research here.
________________________________________ _______________________

cardo0 het imporatant point I have 2 white wires both producing 12V with ignition on which are going to the input of the ballast and one red wires going from ballast to pos of coil. It was like that when I got the car and it ran, not very well but it started right up with a bit of a miss. I marked on the ceramic ballast, 2 white wires in and one red wire out to coil. Is there a slight chance one of those white wires is the starter wire your refering to and should be runniong to ballast outlet to coil for a full 12V versus the way it is now? If so how did the car start when I fist got it?


What you think about my question above about the 2wires....could this be the culprit?????????????????


[Modified by Cali,68,L-79, 8:51 PM 12/3/2003]

 

Ignition coils do have a positive and Neg. If you hook them up assbackwards they still work just not as good...

The resister IS needed otherwise you will cook the coil, too much DC == too much heat == :banghead:

The reason you have 12volts on both sides of the coil is cause the points are open, bump the engine over and the points close and now you have 0 volts on that wire...

As said above it's the sudden stop of electron flow that causes the coils magnetic field to collapse and makes the spark, not the turns ratio all by them selves... Kinda like jumping off a bridge, it's not the fall it's the sudden stop at the bottom.

And no your friend is wrong, hooking 12v up to the secondary of a stepup transformer will not cause it to overheat :rolleyes: Tell him to think about I squared R for a minute

 

:iagree: :iagree:

 

Your absolutely right. I just finished Steve's article and it now purplezes me more why she won't fire.

OH GOD HELP ME!!!

 

:chill: You may not realize it now but this how you learn how things work is when you have to fix them. So slow down and try to make the best of what you find as you will soon be a ignition expert – at least for a 69 corvette.
Not to turn the tables here but I replaced the points distributor in my GTO with an HEI distributor (coil in cap). Nearly 15 years ago but I remember a one wire hook-up. Yes one wire to the ignition switch and a spare adjacent spade terminal for electrical tach. This was a large diameter cap with the coil in the top and a vacuum advance can too. No ballast resistor (or resistor wire) needed. Just barely fit inside firewall. I see Summit sells these less than $200. No mechanical tach drive though. You would have to measure distance to firewall for 69 and compare cap sizes to use on an older corvette. Requires different plug wires too.
Also I liked the idea to let it sit a few weeks and read up on ignitions as its easy to get too far ahead of yourself here. :seeya