# Ignition Coil's



## slowride81 (Nov 21, 2011)

Curious if any ignition coil's are interchangeable with the 1.8L 8v Digi engine in my 91 Jetta. None of my local parts stores carry the oem coil and I need one today. I went to clean the wires going to the coil and broke off the coil plug wire and it got stuck in the coil and in the process of removing it some of the plastic broke and I lost all spark. I've read this coil http://www.summitracing.com/parts/MSD-8202/?rtype=10 has been used. What exactly would I have to do to get it to work? If any other cars are interchangeable lemme know and i'll check the inventory of my local pull-a-part. I know the stock coil would be just fine but I can't wait for one to arrive. I need the car running tomorrow and summit racing is just down the road.


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## WaterWheels (Aug 14, 2005)

slowride81 said:


> Curious if any ignition coil's are interchangeable with the 1.8L 8v Digi engine in my 91 Jetta. . . i'll check the inventory of my local pull-a-part. I know the stock coil would be just fine but I can't wait for one to arrive. I need the car running tomorrow and summit racing is just down the road.
> 
> I can only say that MSD once responded via email that the Blaster2 coil would work for VWs of this era. I tried when I contacted them to gain the primary and secondary resistance values plus windings but they only responded with it will work  That said it is possible it is also the wrong coil for your car. Confused? Don't be as that is just a very simple way to look at a very complicated subject. The coil will work but I can't say it will work best. Best for overall driving would be the same factory coil which came with the car, green or gray label. Any substitute coil will require research to see if it will fit your needs. Hard starting, coil overheating and failure, loss of spark at high engine speeds are some of the downsides of playing around with wrong matched coils. I would advise getting a good used or new exact replacement until you read up on the subject of ignition coils.


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## slowride81 (Nov 21, 2011)

Thanks for the response. I am aware using the original coil would be best. However as I state above I need the coil right now and no one in my area has one in stock. I can NOT wait for the shipping. Need it today. I have seen others have used the coil so i'm going to head to the store and pick it up.


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## antichristonwheels (Jun 14, 2001)

this is no big deal. Go to a junk yard and score a coil. The specific resistances are not of concern. A coil has a primary and secondary winding: 2 coils of pretty long pieces of wire. They both have a pretty low resistance. All coils have to work within the same parameters 12V input and enough output to jump the spark plug gap, 40,000+/- volt depending.

If a given coil is good, be it bosch, MSD, Accel, 16V, 8V, aircooled, it will work on your car.


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## WaterWheels (Aug 14, 2005)

Here are a few quotes from technitians or automotive eletrical companies gathered from a very quick Internet search. I don't really care what people do to "their" cars, their money and all that, but at least make an effort to provide accurate information if trying to help. So do what you like, it’s your car, but you should really take the time to learn what’s correct and not believe everything you hear or read on places like this. If you do any dealings with systems like Mega/MicroSquirt you might have found and needed to use something called “Ignition Coil Analyzer”. If the above was correct it would not be a useful tool.

“A short or lower than normal resistance in the primary windings allows excessive current to flow through the coil, which can quickly damage the ignition module. This may also reduce the coil's voltage output resulting in a weak spark, hard starting and hesitation or misfire under load or when accelerating.
An open or high resistance in the coil primary windings will not usually damage the ignition module or PCM driver circuit right away but may cause the module to run hot and shorten its life. With this condition, coil output will be low or non-existent (weak spark or no spark).”

“Induction ignition uses higher resistance coils compared to CDI is ystems that can use lower resistance coils. So....Do Not Use a "racing" -or- low resistance type coil in an "induction" ignition (or TCI) system unless it is specifically designed for that. The low resistance coil will flow more current thru the TCI and produce the legendary "Hot Toaster" effect. Though it will work for awhile, you will eventually burn the TCI module out.”

“To maximize primary coil energy the primary current (which is squared) must be as large as possible – however there are limits to driver current control and heat generated. The primary inductance also should be as large as possible, with the downside of slowing the primary current charge time and reducing the turns ratio.”

“As mentioned previously, coils are designed with different internal "turn ratios" (sometimes called winding ratios). A coil with one form of winding might make the engine easy to start. But at the top end (high-rpm range), the coil won't function properly. Another coil winding ratio might be best suited for use at high engine rpm, but it won't work well to fire the spark when starting the engine. Because of this, most coils are a design of compromise.”

”If either the primary or secondary resistance is wrong it will result in a lower or higher required output spark energy. This will lead to failure of the coil and possibly other parts of the ignition system. “


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## slowride81 (Nov 21, 2011)

MSD coil installed. Fired up and drove around town some. Running much better than with the old coil before I broke it. Will work for now until I can get a stock one in. Our local junk yards are slim pickings for vw parts and all the parts stores (advanced, oreilly, napa, autozone) all have to order the stock one in. I picked that one as i've seen a number of cars around this forum and others who used it on their similar 8v and didn't have any problems.

Regardless thanks for the info.


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## antichristonwheels (Jun 14, 2001)

Waterwheels why do you feel the need to be some "know it all" when really it's obvious you don't know jack?

Notice the MSD coil is working

as would an Accel or Mallory or blue Bosch coil from an aircooled and many others.

He's not using MS, he doesn't have CDI ignition. It's a stock Jetta. Your esoteric BS is what is not helpful. This guy's trying to get on the road and you want to hear yourself wax on about a subject you are obviously clueless about verified by the fact that you must use Google to come up with anything to say. You apparently don't have the knowledge to even suggest a solution. Perhaps YOU want to work to be more helpful and less of a gasbag.

http://www.ebay.com/sch/i.html?_nkw...ts+coil&_osacat=0&_trksid=p3286.c0.m270.l1313


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## WaterWheels (Aug 14, 2005)

antichristonwheels said:


> Notice the MSD coil is working


Notice I said in my first response to the original question that yes it would work but could not say just how well. Notice that I said via an email response from MSD that they said it would work, but failed to provide any detailed information about their coil (unlike some other companies?). Notice that I listed some of the drawbacks to using a wrong coil and NOT a warning that using that coil was going to blow up his car. Notice that I advised using the factory correct coil, advised not demanded, until he reads up on the subject. Notice that your response was “The specific resistances are not of concern. A coil has a primary and secondary winding: 2 coils of pretty long pieces of wire. They both have a pretty low resistance. All coils have to work within the same parameters 12V input and enough output to jump the spark plug gap, 40,000+/- volt depending.”, which is not very correct. You did get the fact that they have a primary and secondary winding at least. Do we need to NOTICE anything else?



antichristonwheels said:


> as would an Accel or Mallory or blue Bosch coil from an aircooled and many others.


As you don’t list just which of the Accel, Mallory or air cooled coils you mean I can’t comment on those, but I can on the blue Bosch coil. It is designed for points type ignitions if it is the one I believe you are talking about? The primary resistance is 3.4 ohms with a secondary of around 7.9K ohms. Why would anyone suggest using an ignition coil that falls far outside the values that a repair manual says it should have or should be replaced? Point type ignitions and TCI (TSZ for VW if you like) both use different dwell times and is exactly what some of those “Googled” quotes were talking about. Will an engine with a TCI (TSZ) ignition start and run with that coil installed, yes. Will it run 100% correctly? No. Will it work until you get the correct coil? Yeah but don’t wait too long or a new ignition control module may also be in order. Yeah, I know, “I have a friend . . .” or “I have been using that coil for twenty years on my . . .” or some other personal fact that nobody can confirm or deny. Don’t care. Either show that what I said is wrong with something other than boo hoo responses or just leave it be.



antichristonwheels said:


> He's not using MS, he doesn't have CDI ignition.


I fail to see just why you said this? Did I somewhere say he was or indicate he was? Maybe you just did not comprehend what was said. Could that be the case?



antichristonwheels said:


> Your esoteric BS is what is not helpful.


First the word esoteric somehow just does not seem to fit into what you are saying. Second if I recall he gave thanks for the response/information. That would indicate at least to me that some help was given. 



antichristonwheels said:


> . . . a subject you are obviously clueless about verified by the fact that you must use Google to come up with anything to say.



An expert in any way shape or form? No. But you saying I’m clueless on the subject is something I have determined you are not qualified to really say. You are correct in that I did Google the topic. My words did not seem to be enough for you to believe, which is fair enough, so I decided to do some quick “supporting” document searching. But if you ever feel you would like to do some real time one on one discussions, we can do that also. We just have to work out a time, different time zones and all that, and a topic. A few rules, like how many minutes are allowed between posts and such, and we can go at it. 



antichristonwheels said:


> Waterwheels why do you feel the need to be some "know it all" when really it's obvious you don't know jack?


This seems to be the “classic” response given when feelings become hurt due to being corrected about something posted which was incorrect. That and a response which does nothing to confirm the statement or to show that their being corrected was in fact wrong and they were really correct all along. That’s a shame as I expect more from people who try to label me in some bad way as a “know it all”. Although I don’t think of myself in those terms or to be some kind of expert, I must know more than they do as they can never find the words to correct what I’ve said, strange.


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## antichristonwheels (Jun 14, 2001)

You are so full of it just more BS talking out your backside.

how is a higher resistance primary going to put a strain on the ignition module when it actually draws less current?

the more you blab on it becomes more and more obvious your electronics knowledge is not there. 

Perhaps YOU want to work to be more helpful and less of a gasbag.


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## WaterWheels (Aug 14, 2005)

antichristonwheels said:


> . . . how is a higher resistance primary going to put a strain on the ignition module . . .


Exactly my point, you don't know but will sit there trying to convince others that I am wrong and you are right without explaining anything, nothing, just flinging around playground insults. Talk is cheap as they say, did you get yours on sale?


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## antichristonwheels (Jun 14, 2001)

Once again you display your total ignorance of electricity.

Did you ever notice while VW/Audi used several different coils on different engines and years of cars, but the transistorized ignition module is the same 8V, 16V, Fox, Jetta???

What law did you break that you had to join the army? Did you claim ignorance of the law? Was it Ohms law?

Perhaps YOU want to work to be more helpful and less of a gasbag.


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## slowride81 (Nov 21, 2011)

Its all good guys no reason to argue. Coil is working (its the least of my problems right now) and that's all that matters. Down the line sure i'll get a stock coil but right now with the holidays and this piece of junk taking all of my money I just can't afford the premium for one and I need the car to get to work.


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## WaterWheels (Aug 14, 2005)

Yep, they do have a few different resistance values. Range is like .50 to .80 ohms on the primary side which is no problem for the driver but a far cry from sticking in a 3.4 ohm resistance as a replacement. So what exactly is your point? You throw little nothings in here and there which don't really explain or say much but you seem to feel they are the great debate winners. And fill the rest of your responses with cheap personal attacks which really don't phase me (I've been around to long to pay attention to garbage like that). So how about you skip the next urge to say something stupid about me as a person, who you know nothing about by the way now do you, and say something intellegent related to the difference of opinion we have. That is your claim that, not a quote mind you so don't jump in saying that is not what you said, a coil is a coil and they all work the same and any coil that works would be a fine replacement and can't cause any damage. It's really simple, I stated something which you more or less said was wrong, I posted a few quotes from sources which can be found if one cared to research and you started getting wierd (to use a nice term). So try to focus on the real topic at hand if possible and not waste so much time dreaming up feeble attempts at character slander. Nobody likes or admires people who have to resort to tactics like that to gain attention.


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## WaterWheels (Aug 14, 2005)

slowride81 said:


> Its all good guys no reason to argue. Coil is working (its the least of my problems right now) and that's all that matters.


Everything is fine with me, not to worry. Your situation was at least for now patched up and that's fine, end of your story really. This is not personal, at least for me, and I enjoy a good debate. I'm just trying to get one if there is one to have, but there really isn't it seems. If nothing concrete springs up here real soon and just the same old ranting I'll stop responding, thats often the case anyhow.


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## antichristonwheels (Jun 14, 2001)

[email protected]


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## antichristonwheels (Jun 14, 2001)

you did know that resistance of the coil does not determine output?

Can you share with the studio audience the problem with going from a coil with a 2Ω primary to one with 3.4Ω?

You seem to know all about it so please go ahead.


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## antichristonwheels (Jun 14, 2001)

Can't you stop yourself??

What kind of compulsion drives you?

They have wireless in foxholes?


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## antichristonwheels (Jun 14, 2001)

Your momma's so fat, she sweats gravy.


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## antichristonwheels (Jun 14, 2001)

What if you add a ballast resistor? OMG more _resistance_ what happens then? Does the car catch on fire or what?


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