Anyone Ever Have A Coil Do This?

I have seen this happen before. Was not on any car I ever had though and I do not know what causes it. Hopefully someone will chime in on this one. High voltage not being masked well enough perhaps??

 

I have had an MSD Ignition system on one of my racing jet-skis after multiple box and coil failures i decided that it was not worth the trouble. One thing to realise is most of the MSD parts are made across the border from there El Paso, Tx HQ. I have a feeling that there is not much in the way of quality control in the plant that makes there parts. If you like the MSD ignition box you might want to look at using a coil from Accel, Nology, or some other ignition system Mfg. The MSD Box will not know the difference in coils just look for one that has the same primary resistance as the MSD coil.

 

What plug wire resistance did you have per foot? Rotor to terminal gap and plug gap?

 

I have seen something similiar, on my 308 2v the posts inside the dist caps were 'notched' like a lathe was used on them. Dave fixed it for me & may still remember. From what I remember; it was my error for not ohming out the new spark plug wires. The end result was fried rotors & caps...Ouch

 

I have seen something similiar, on my 308 2v the posts inside the dist caps were 'notched' like a lathe was used oon them. Dave fixed it for me & may still remember. From what I remember; it was my error for not ohming out the new spark plug wires. The end result was fried rotors & caps...Ouch

 

MSD is not tollerant of high levels of RFI, not shielded well enough to use solid core wires. High resistance in the secondary circuit will make the spark search for an easier route than jumping across the plug gap at very high combustion pressures..... high plug wire resistance, large rotor gaps, large plug gaps, lean mixture in high CR engines..... or you had a coil that got damp under the boot. Never that easy but one has to find the answer before throwing money at new components.

I have used just about every MSD box they make and have not had problems with them other than those caused by voltage spikes.

I still remember your's Mike...quite a sight!

 

MSD literature claims to only use their coils, is this marketing?
I was doing a pre-roadtrip inspection the week before a journey and checked the coil connection and saw some oil had weeped into the MSD primary connection so went to buy a new coil. The MSD coil cost me $50, must be something special or I'll be embarassed

 

The main reason that MSD wants you to use there coils is 1. to sell them and 2. they have not tested there units with other coils.

The fact of the matter is a coil is nothing more than 2 sets of wires wound around an iron core. If an MSD Coil and Accel coil has a primary resistance of 2-3 ohms have essentially the same length of wire on the primary. On the secondary side the more resistance the more wire or windings it has therefore the potential to produce a stronger spark.

Take a coil that has 1000 windings on the primary and 5,000,000 windings on the secondary will have a 1 : 7500 ratio in theory if the battery is supplying 12 volts to the coils primary the secondary can produce 60,000 volts in theory. A fresh properly gaped spark plug should only need 10,000 volts to induce combustion. If you increase the gap, or compression you will need more voltage. If a spark plug is carbon, oil or fuel fouled a spark may not be produced as the voltage will take the path of least resistance through the fouling. A coil leaking oil or the coil wire being wet can cause the voltage to arc and find its way back to the coil.

The basic principles of an ignition system really has not changed a whole lot other than the introduction of electronics to allow advance curves to cater to different engine loads I.E 3D Advance map.

With the wires a Solid core wire will have very little resistance as it uses solid wire in the center core but will produce lots of RFI causing issues with modern ignition, EFI systems Etc. The modern suppression core wires use carbon as the conductor and has higher resistance this suppresses RFI but requires more voltage from the coil to produce the spark. The biggest problem with suppression wire is the fact that it is fragile and can be damaged quite easily causing lots of headaches with the ignition system.

Recently I had a bike in the shop that the customer had installed suppression wires and it ran like crap. With coils having to produce 30Kv to fire new spark plugs. After switching over to solid core wires the bike now runs great and only needs 6kv to fire the spark plugs.

 

I havnt ever saw a coil do that, but when I was young I saw a lot with points cars burn down the side of the tower. High resistance in the secondary ignition from poor plugs, extenders, wires, cap, rotor, etc., or dirt, grease, moisture and oil. Or a little mix of everything? They are the enemy.

Its amazing the car even ran. And a heads up, there was an open spark visable there, any potential fuel leaks present would have had a great ignition source. One more reason to be ever watchful between service periods. And any time you have a miss is a good time to investigate. A good miss can overload the cat with fuel and set it on fire. Which in itself is a good reason not to have cats, if you can get away with it.