Lumenition MS 3 coils and magnetronic

[sclemow]

Does anyone have any experience of the Lumenition MS3 coil?

This is recommended for use with the magnetronic ignition module that I'm using, it looks like it is a ballast coil permanently ballasted though.

S

[Smiffy]

Are you sure the resistor, doesn't come as a separate module ?

[sclemow]

It does come as a seperate resistor but they recommend connecting it.

http://www.newtronic.co.uk/new/support/ ... n_v1-1.pdf


S

[dklawson]

I have no experience with that coil but I have reviewed the document you linked and additional information about it at the link below.
http://www.gsparkplug.com/shop/electron ... ronic.html

Yes, it is a ballast coil and per the Magnetronic and Lumenition datasheet they say that you must use a ballast resistor with it. This is not complicated to do. You will connect your car's existing 12V white coil wire to one side of the resistor, then run a second white wire from the remaining resistor terminal to the coil. The hardest part will be finding a place to mount the resistor. You don't have to do anything else to use this coil.

When people complain to me about the pink resistor wire used on many British cars with ballast ignition systems, I typically suggest they replace the pink wire with an external 1.5 Ohm ballast resistor like the one that comes with this coil. There is nothing inherently wrong or complicated with a ballast ignition system or ballast ignition coil. The problem is the reliability of the pink resistance wire that several British cars used instead of an external ballast resistor.

[sclemow]

Hi dklawson

Thanks, yes I'm not concerned about wiring it in. I was wondering whether anyone has experience of them and their performance. In most ballast systems the resistor is used as a cold start aid to bypass the ballast resistor and run a 6v coil at 12v while turning over. This is always running at the lower voltage. It's not clear to me that this is an advantage over running a standard non-ballast 12v coil. It may be if it the ballast resistor always allows a >6v voltage for example and therefore a stronger spark. Or it may be just because lumenition only make a ballast coil and therefore suggest using it in both applications.

Cheers

S

[dklawson]

I see your point.

I could not find published specs for the MS3 coil on the Internet. If you knew the primary winding resistance of the MS3 you could add that value to the 1.5 Ohms of the ballast and determine a target primary resistance for an alternate "standard" coil. Matching the total resistance would insure that your alternate coil did not pass too much current through the ignition module. Knowing the target resistance would indeed allow you to select a coil with higher output voltage if you wanted. However, keep in mind that the extra output of the coil will not help you much until you open the spark plug gap up.

Forgive the following cross-forum link.
http://www.theminiforum.co.uk/forums/to ... coil-help/
The OP posted the following information from his Magnetronic packaging:
"These units will be damaged beyond repair if connected to an ignition coil with a static primary current greater than 6 AMPS. Coil resistance must be 2.5 OHMS or more and the coil itself must have a resistance of at least 1.5 OHMS."

Based on that limited information, any standard coil with a primary resistance close to 3 Ohms should work.

[sclemow]

Thanks Doug,

I agree and read that on my packaging. To be honest I can't see why they recommend a ballast coil.

The issue has sprung up as my really doesn't want to start when cold with a lucas high power coil. I've been through the high current connections and have reduced the drop as much as possible, looking at the spark it is there but looks very weak. I am therefore going to put a new coil on it, but thought I'd better take a look at the recommendation from lumenition first to see if I'd missed anything.

Cheers

Simon

[mk1coopers]

I've just ordered one of these, not that I'm thinking I will be getting some great BHP gain, I'm just trying to make the system a reliable as possible. I've spec'd the high vibration epoxy filled unit, as being attached to the dynamo on an A series engine must qualify as a high virabtion fitment

http://www.minimania.com/part/40611/Coi ... erformance

[ianh1968]

My view here is that the ignition system as a whole will have a total resistance specified in.
This could be, say, 3 ohms. Thus the total can be achieved either using a standard
type "12v" 3 ohm coil, or a "6v" 1.5 ohm coil along with an additional 1.5 ohms worth
of resistance....

I put the "quotes" round these voltages because I am pretty sure that the coils effectively
only have a "fixed" resistance. Electrically, the voltage is not technically relevant in the
actual coil's specification other than making sure the internal wiring is the correct thickness.

It's the current handling of the switching device, points or transistorised, that is important.
Not enough resistance in the circuit and it may melt/overheat/fry, too much resistance and a
weak spark will be the result.

If you use a standard type "12v" coil, you CANNOT have the start/overload facility.
If you use a ballasted system, you CAN IF YOU WANT TO...

A ballasted system may give the better chance of a good startup, which is why it was introduced.
Using this gives the after-market equipment the best chance of appearing impressive...

"It works great, once it gets started", etc doesn't sound so good!

Doubtless someone here will blast a hole in my theories...

Ian

[dklawson]

No hole blasting of theories from me. I completely agree.

If the cold engine is hard to start with a "standard" 3 Ohm coil you could fit the ballast coil, ballast resistor, and (if necessary) change to a 4-terminal solenoid that provides a connection for the bypass wire. As Ian said, the ballast system was developed specifically to address hard starting when cold.

[sclemow]

I agree, but it's somewhat off topic. I'm not trying to decide upon a ballast versus non-ballast system from the point of view of the cold start. It "should" start fine from cold with either system. I suspect the coil is at fault because it is degraded and broken.

[dklawson]

Symptoms of coil failure can include things like a sudden loss of ignition when the engine/coil get hot. A misfire that occurs at higher engine speeds can also be symptomatic of (but not exclusive to) a coil breaking down. Many coils are oil filled so leakage from a coil indicates a definite need for replacement. If you have a tachometer fitted to your car, issues with proper operation of the coil can often be seen as erratic behavior of the tachometer's needle. If you are not experiencing any of those problems, hard starting is not likely to be associated with the coil.

Sorry if the thread took a different direction than you wanted. Based on the notes on the box, any performance coil you select that has a primary resistance close to 3 Ohms will work and will not exceed the current limits of the electronic module.

[sclemow]

Hi Doug

No problem on the direction change, thanks for the reply. The reason that I am looking at the coil for the cold starting is because of the weak spark. The leads, cap and rotor arm have only done about 3k miles and look in reasonable condition. I have been through the high current and earth connections to reduce any voltage drop when turning over. I have put a new solenoid and different starter motor, so there is relatively little left.

It has been on Steve Harris's rolling road since developing this and we are sure that timing and mixture are ok.

Obviously there isn't that much that an A series needs to fire up, so I was looking at the coils.

My inclination is to go with a 12v non-ballast one, because, I really can't see a gain in using this unless I implement a ballast circuit and change the solenoid. This isn't difficult but it is curing a symptom rather than the problem, I want to trace the issue really.

Cheers

Simon

Simon

[ianh1968]

Sorry, from me too if what I said was "off topic"...


It sounded like using the ballast resistor on a 1.5 ohm system may be "optional".

It does come as a seperate resistor but they recommend connecting it.

Hence me talking about the electrical considerations, and the implications of
not having the correct total system resistance...

I went from a ballasted system to a 3 ohm non-ballasted system on two
vehicles recently and have suffered no bad side effects...

I am using (tarty) Pertronix FlameThrower "Chrome" ones.

Ian

[dklawson]

Simon, I am sure you have looked at this, but is there a chance you have combined resistance type spark plug wires (and/or reistor caps) with resistor plugs? Though I doubt this is your situation, it is possible to combine carbon core wires with resistor cable terminals and resistor plugs. Using too much resistance in the plug wire circuit will weaken the spark.

[sclemow]

Hi Doug

Interesting, great idea, I hadn't thought of that. I'm sure that the plugs aren't resistor ones, they are standard ngk bp6es's. I hadn't realised that the core and caps were different.
How would I tell?

I am using this lead :
http://www.gsparkplug.com/shop/misc-cor ... g-ybs.html

and these caps :
http://www.gsparkplug.com/shop/spark-pl ... cx600.html

I was looking at the spark between the cap and plug with one of the spark guages that you can plug into the cap and rest on the plug then lengthen the gap to look at the spark. Although it would travel a reasonable distance it looked weak.

Thanks for your ideas, it's very helpful. I'm kind of struggling a bit as there really isn't much in the system!!

Cheers

Simon

[dklawson]

The bumblebee wire is solid core. The Champion caps say "with suppression" which means they have the resistance. Since you have BP6ES plugs the only resistive element in each line should be the Champion caps. Nothing there should be causing excess resistance for a weak spark.

Try a test without the inline tester. Remove a spark plug and rest it on the engine block in a dimly lit area or shadow with the plug wire attached. Have a friend crank the engine on the starter. The spark across the plug electrodes should be sort-of Bunsen-Blue with perhaps small orange sparkles. That is a healthy spark. If instead the entire spark is orange, try a new condenser. Beyond the condenser I'm not sure what would be causing a weak spark with the ignition parts your car has.

[Frogeye61]

Hi dklawson

Thanks, yes I'm not concerned about wiring it in. I was wondering whether anyone has experience of them and their performance. In most ballast systems the resistor is used as a cold start aid to bypass the ballast resistor and run a 6v coil at 12v while turning over. This is always running at the lower voltage. It's not clear to me that this is an advantage over running a standard non-ballast 12v coil. It may be if it the ballast resistor always allows a >6v voltage for example and therefore a stronger spark. Or it may be just because lumenition only make a ballast coil and therefore suggest using it in both applications.

Cheers

S

(My wife says i should put in a disclaimer. I m more a techno nerd than a communications specialist. I hope I don't bother anybody with my communication skills or lack thereof.)

There sure is a lot of information and subjects to consider, all contained within this short thread.

Regarding the lumenition coil. If it is designed for the ballast resistor, it is because the internal resistance is low enough that not using the resistor will overload the controlling circuit. But this much has been covered several times within the thread so far. What I didn't see is that while the coil used with ballast resistor has less primary resistance than a coil used with a straight 12V supply. Thicker internal wire will reduce primary resistance, therefore requiring another resistor in series (the ballast resistor). Changing the secondary/primary winding ratio will increase the secondary voltage as compared to primary voltage. If the primary voltage were kept at 8 volts while using the ballast resistor - or at about 8 volts while starting the engine and bypassing the ballast resistor, the the secondary voltage is kept at a value high enough to generate the necessary spark - and a bit more.

If it is recommend using the ballast resistor, then use the ballast resistor.

Resistance in secondary wiring (high tension cables) doesn't act completely like resistance in low voltage wiring. Your house current at 400V is still low voltage. High voltage (30000 - 50000V)is something completely different. We must first notice that the gap in the spark plug is pretty much close to infinite resistance. Adding resistance to the secondary wiring has the effect of increasing the voltage that jumps the spark plug gap. This is a good thing because voltage - not current, is what will jump the gap. A larger gap is helpful in igniting fuel that is otherwise not completely distributed within the combustion chamber. Especially necessary during starting or lean conditions like highway driving.

Then there is the little twist with phase change. Though the car uses DC power (this is best when using batteries), the ignition system acts more like AC power. This is because the ignition system is constantly switching the coil on and off. The frequency of this switching being proportional with engine speed.
The end effect with a coil (inductor) and a capacitor is to give a phase shift between the voltage and the current. A pure inductor gives a 90 degree phase change in one direction, a capacitor 90 degrees in the other direction. Pure resistance gives no phase change. But pure resistance in line with the power supply will effectively reduce the phase change of either component.
The relative values of the inductor and capacitor will determine at which frequency the input, and therefore the output, voltage will remain in phase. A pure resistor (ballast) therefore reduces phase change and consequent energy loss.

Energy in the spark.
If the voltage and current are kept in phase, the energy will be highest. This is what you see when you look at the spark. Problem is that the phase at idle or cranking speed is not the same as the phase at high speed where the engine power is really generated.

Then the compromise. Better spark for starting, or better spark at maximum engine power. I choose both. Therefore bypass the resistor for starting, but use it for driving. The coil is designed for this as a pure upgrade from the antiquated system otherwise used from 1910 until the late 60's

edit: Yes do like above. Try a new condenser.
D.

[sclemow]

Hi All

There isn't a condenser, the magnetronic ignition is a points and condenser replacement.
I'm going to try another coil tonight and see what the spark looks like at the plug.

Cheers

Simon

[dklawson]

There isn't a condenser, the magnetronic ignition is a points and condenser replacement.

DOH !!! Of course you are right!!
I apologize for not remembering you had already installed an electronic ignition.