Ignition coils - silly question of the day

Ehhhhhhhhhhhhhhh... I thought you might say that. Not *YOU* exactly, but... "the wise voice of the internet"

Too many unknowns for me, which is why I wanted to ask in a general, hypothetcial sense, for my edification, what the likely effect would be.

FYI...

1. Car came with an electronic ignition module but I can't identify it. It doesn't seem to be an exact match for all the usual suspects. It has no identifying markings.

2. Car may or may not have a "Eureka Bypass Wire". This is apparently a thing on SOME Scimitars, but not all Scimitars, despite being VERY IMPORTANT. All attempts to work out what a Eureka wire might look like and where it might go have proved at best to be fruitless and at the very worst to be utterly bamboozling. Various people who feel they really know what it is have said totally contradictory things about what it is and where it is. Sometimes it isn't even a wire, and it it doesn't bypass anything it bypasses the bypass, or something. At one point it was confidently stated that it was attached to the starter motor... until I photographed it and asked "IS THIS IT?", at which point it wasn't, and then nobody knew what the wire I'd photographed was but felt strongly it might indicate that it might be important and could be a clue to something that I hadn't even asked about. Then shortly after that, it was a wire buried deep inside my loom and could only be present if it couldn't be seen at all, and if it could be seen... I may not have a Eureka wire, and this may or may not be a good thing, in a bad sense. Then it was something best detected by sniffing the glove box. If it smelled of socks, I had to cut my loom in half and look for the blue wire, which would mean I hadn't found the Eureka Wire but I should keep looking. Then I was told to attach some wires to some wires, and run another wire from the battery to the cigarette lighter whilst revving the engine to 6000rpm. if the reading was NOT less than what would be more than what it is when the engine is NOT idling and the radio was turned down on a Thursday in July, it might be that it is NOT what is a Eureka wire that isn't, and therefore is, and therefore, something something head asplode.

3 (Subsequently) the coil fitted may be a ballast resisted coil or it might not be. There are no indications on what's left of the label, and unlike most other coils the Flamerthrower 2 coil is never ever described anywhere as a ballasted or non-ballasted coil. It's just "a coil", a super powerful coil that laughs at ballast and kicks it out of the vehicle. Everyone else's coils say "Ballast resistor required" or "Not for use with a ballast resistor". My knowledge of electrics, coupled with the bone-meltingly confusing and contradictory information I've had about the Eureka wire, have left me feeling ever-so slightly less than utterly clueless about what the hell to do. The safe option is: Just buy another Flamethrower 2 (£45), but part of me thinks "What if that was just a spare coil kicking about when one was needed (it looks ridiculously old and rusty) and it just happened to work quite by chance, but I would actually be better off with a different resistance rate and a coil with less fancy graphics on it (£17).

I think I'll just get another fancy-pants "Awesome Dazzle Effect Flamethrower Megatron 5000 Lightning Godwrath Megacoil" and stop thinking about it.

You do tend to find lots of contradictory b@ll@x information on Facebook

It's a eureka wire, not a eureka bypass. It drops the voltage to the coil during normal running to about 9v.

It's bypassed during starting because the starter pulls a lot of current, so the coil sees about 9v on a ballast or non-ballast system. Theory is that a coil designed to run on 9v will provide a stronger spark during starting than a coil designed for 12v.

On a 5/5a the standard eureka wire is in the loom between rev counter and coil. All 5/5a have them from new. SE6 on have a remote wing mounted ballast resistor.

Ballast coil is 1.5 ohm primary resistance (such as Lucas DLB102 or 110), non-ballast is 3 ohm (such as Lucas DLB101 or 105). With electronic ignition and no ballast you could run a 1 ohm DLB198.

The Pertronix flamethrower are meant to be very good - they use a lower primary resistance for a higher voltage output - that's only really a benefit at high rpm where the coil has to fire every few milliseconds.

The same theory holds though, if you run a ballast coil on a non-ballast system it will overheat the coil and quickly burn it out. If you run a non-ballast coil on a ballast system, it won't see full voltage (poor spark).

So you must find out if your eureka wire has been bypassed or not before changing the coil.

Here's something off the web that's written quite well - I've made one sentence bold and removed some references to motorbikes.

An ignition coil is actually made up of two coils. Just like a model train transformer, an ignition coil has a primary winding (or coil) and a secondary winding (or coil). The primary winding is the half of the ignition coil that connects to the battery, the secondary winding is the half that connects to the spark plug. In between, the aforementioend amplification takes place to convert the battery's low voltage to the high voltage needed by the spark plug. The actual conversion process is called "mutual induction.". It's rather technical and not all that useful to our discussion.

What is a "High Performance" Ignition Coil?

Ignition coils being production items, no manufacturer puts one on their vehicle that is more powerful than necessary, so typically they are constructed with a ratio of primary to secondary windings of, say, 50:1 (example only). That is, the primary's thick wire is coiled onto itself, say, 150 turns while the secondary's thinner wire has 50 times as many turns (7500, in this example), resulting in an increase in voltage, just as in a transformer. The two windings are wrapped one around the other, concentrically, with the primary winding being on the outside, usually. (Why "usually" is not important, but some ignition coils are built the other way, with the primary winding in the middle instead of on the outside.) The center of the ignition coil, around which the two windings are wrapped, is a steel core. This core gives the magnetic field that appears inside the ignition coil a concentration point, which strengthens the field, improving ignition coil performance.

The traditional high performance ignition coil is one that has a different windings turn ratio than stock. So instead of the 50:1 mentioned above, the ratio might be 70:1. That is, the secondary winding has many more turns than the stock ignition coil, resulting in a higher voltage output. This costs money of course, so some makers of high performance ignition coils take a different tack, and get that 70:1 ratio by reducing the primary turns instead of increasing the secondary turns. This is legitimate, and the result is exactly the same, except less money is spent, the coil doesn't end up being larger, no larger shipping boxes are needed, etc. But as with everything, there is no free lunch. The primary winding is connected to the battery, remember, and being smaller than stock means less resistance than stock, which means more electrical current, more loading of the ignition parts connected on the battery side -- most notably the points -- and of course, more heat and wear. Metallic contact points can withstand this added strain, though with accelerated wear, but the electronic boxes that replaced the points on later machines' electronic ignitions cannot, quickly overheating and failing. This is the main reason the sellers of high performance ignition coils offer two main choices, low-ohm and high-ohm models. The low ohm is suitable for points ignitions, the higher for electronic ignitions.

How Does a High Performance Ignition Coil Help Performance?
A high performance ignition coil helps engine performance four important ways. First, the higher voltage allows for a larger spark plug gap, which results in a more robust initial flame kernal at the start of combustion. The result is a real-world engine torque increase. Second, having more voltage on tap means the voltage required to bridge the spark plug gap gets there faster, leaving less time for voltage diversion through the spark plug's inevitable carbon deposits. Third, the higher voltage potential creates a stronger "push" on the electrical stream to the plug, resulting in increased electrical current, i.e. more energy, more snap. Fourth, with more voltage available, there is more in reserve for non-standard situations such going uphill on poor fuel on a hot day.

Well, I finally managed to work out what my e-points are. It's an Accuspark module. I have to assume it's the right one for the Essex as it works (Accuspark kit17)




Nice that someone seemingly had a go at painting it white. Always important to try out new things.

Why do you think the coil is on its way out, I've got a 70 year old coil that still works?

£7 for 8 NGK's is suspiciously cheap. I decided to order a spare set from Burton or Demon at the start of the year because nobody seemed to have them in stock locally. I think 6 cost me about £35.

I find NGK's to be generally very good, but I also know that my car has seemed to possibly eat them quite quickly so far in my ownership. The ones the car came with were old and actually snapped off at the ends, which quickly explained and resolved the misfire it developed on the first journey home.

New set and the misfire went away, never to return. having changed the plugs for myself, I can see how the tips can easily get snapped off if you aren't very patient. It's a B**ger of a car to get a couple of the plugs in and out. It would be easy in a moment of haste to try and wrench your wrench out and to pull at the lead tip whilst doing so.

About 6 months later though I suspected it might be running a little bit clumpy... not a misfire as such, just not as good somehow. So I decided to pull all the plugs to see how they had fared. Overall they were looking okay, but I had an old, partly destroyed carburetor and it was clearly over fuelling. What was left of it was patched together with tape and cable ties so I didn't attempt to adjust it. Swapped the plugs anyway, then later on fitted a new carb.

At that point when I changed out my plugs, the rearmost driver's side plug looked wet, so I feared a greater problem.

Next time it started to feel a bit crabby, I decided to only swap that plug over. By now I had the new carb on so things were better all round. It looked a bit wet again but not so much. In hindsight I suspect I may have dripped oil when pulling the dipstick at first.

So I've just swapped them again purely because... new coil... so new plugs, but it probably didn't need them swapping again so soon. They looked okay.

This time the wet plug was not wet at all. It was dry. The plugs looked good, but whether it was the coil swap or the plug swap, or both... my car is now like a hungry attack dog straining at the leash.

= )

Just checked... £12.18 from BurtonPower.

I must be thinking of something else.

First set I bought was from Halfords (Don't knock it, it was close by and I needed them)

Halfords price.... £FOUR QUID EACH!!!! HOLY MAZUMA!