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Exploding coil


Dano
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Has anyone ever had a coil explode or pop open? I just had the ignition on for the radio and was working at the back when I smelt this rather nasty smell, a cross between oil and plastic burning, checked all over couldn’t find anything, took the battery terminal off just in case and this is when I saw the clear fluid over the bay, then noticed that the top of the coil was hanging open and the casing was very hot

Any idea why this should happen?

Could it be my radio wiring? I wired it into some free connectors on the back of the fuses, one was perm 12v and one was 12v with the ignition,

I have put a tester across the coil wires and nothing changes when I disconnect the radio so I cant see it being that

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They always say not to leave motorbikes ignitions on as it does that but as the others have said I've never seen it happen, although I did melt one of the connections (the solder melted) on a coil on a GS850, by leaving the ignition on overnight

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When putting 12V through a coil, it is going to heat up over time, without the rest it gets from producing a spark and the airflow from the engine they get too hot to touch pretty damn quickly.

Never ever ever leave your ignition in the II position for more than about 5 minutes if the engine isn't running -this sort of thing is not uncommon on the older vehicles at all, newer ones (EFIs etc) switch dont energise the coil initially, so do not suffer the same problem.

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Thanks for the replies, I also talked to an old-school mechanic who said that cheap coils do suffer from this, if you shake the coil and can hear the oil sloshing then there is not enough oil in there, these paddocks coils are £6 so I guess that is half the problem

I think I will fit a leisure batters and split charge then run all ancillary from that including the radio and a performance coil as suggested on other threads

Thanks

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Is there someway you could adapt to this with a sort of smart relay, to only switch the coils on when the engine is running? :mellow:

or just pull the LT leads if you are sitting there with the radio on waiting for a recovery truck

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Yay! I sense not only a special switch but also an added security feature? <_<

You are right! I used to do this one some of my old cars, hidden switch from the LT under the dash, I was actually going to do it on the landy but didn’t think that it would be useful in this way

I also have one of those race type start and toggle ignition switches I was going to fit under the bonnet on the bulkhead to help with starting and turning over when tinkering so I guess I could wire the toggle to the LT and the push button to the solenoid, it would be the same as connecting it to the ignition in parallel

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Is there someway you could adapt to this with a sort of smart relay, to only switch the coils on when the engine is running? :mellow:

Hi Guys,

Sorry to get a bit technical but a bit of background on the ht system on your ignition system.

The coil is essentially an ac based component, a transformer if you like, converting low voltage 12v to 1000s. This is fine when the engine is running as the 12vdc is being switched on and off each time a spark is needed so it would seem like an ac voltage to the coil.

Unfortunately when just left on with no need for a spark there is permanent dc and coils do no like dc. They usually heat up, burn up and die! Or explode as with yours. Possibly yours was oil filled. Therefore i would think your stereo was not the culprit this time!

Being an audio enthuiast i also like to have a few sounds. My solution was to fit a Range Rover ignition switch that has an accessory step. This would power only the stereo. When you start or go to IGN you did another turn. Most series vehicles only have OFF, IGN, START.

What you would need is one that does OFF, ACC, IGN and START. Can be from a Range rover, Defender but these would need adapting. Maybe VWP have something?

You can have a seperate switch for the stereo. Most newer stereoes are only looking for a 12v sense rather than a supply, but i found this a bit inconvient in use.

I would recomend a new or different ignition switch. You could adapt a car one if necessary. They are all basically the same i would have thought.

Hope this helps. Sorry if i have gone over something already covered but i have been compiling this for a while!!

Cheers

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I agree with Monster -

Even if you have a 6 volt coil fitted 12v is only applied during cranking position so the DC current flow which is probably quite high coupled to a defective or low quality coil could cause fun and sparks.

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my stereo is wired to the ignition switch. I have off, acc, ign and start and im certain its the original switch :unsure: I took the fusebox out and found that the fan was controlled by acc position and there was a spare spade terminal on back of the fuse so i used this as the swicthing feed on a relay and took power to the stereo through the relay.

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If I remember corrctly it depend on wether the points are open or closed when the engine stops. Just my two penneth :P

The engine is pretty unlikely to stop right at the top of a compression stroke tbh, so the points are more than likely going to be closed, but you are right, if they were open it wouldn't be a problem.

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I have had the same problem but on another vehicle (not my landy), was working away with the radio on, hiss of gas, the coil popped and brown gunk oozed out of the top.

Did a few posts on the owners club and the consensus was:

i am running an old ford pinto engine that requires 9v coil running off a 12v battery. something to do with the extra voltage required to boost on start up and then runs at 9v when driving. To prevent the coil burning out there is a 'balast resistor' that the coil supply runs through.

When you replaced your coil, did the old one have a balast resistor? does it need one?

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If there's a ballast resistor there will an extra small terminal on the solenoid. The resistor itself is a piece of (pink, with the word "resistance" printed along its length) wire connected to this terminal and the + terminal of the coil.

SIIIs didn't have this as standard, and you need a 12v coil (no ballast) for the Maplpin ignition amplifier.

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All I have is the +ve lead from the loom, the –ve goes to the condenser and the HT lead

Its running a standard coil which I presume is 12v, isn’t it?

I have a Maplin amplifier to fit, surely it will work with the standard coil

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  • 2 weeks later...

Here's how I solved the radio problem in my 2a.

I ran a wire from the permanent live fuse, through a switch and spliced it onto the radios' +ve feed, the one that runs from the ignition.

And most importantly, I cut the +ve feed (from the ignition) wire & put a diode in-line to prevent current running back through to the rest of the loom.

Like everyone else has commented, if you leave the ignition on without the engine running the coil will heat up alarmingly, without the constant circuit breaking from the distributor it's just a coil of wire, same as a light bulb or old fashioned 3 bar electric fire.

Here's a pic of the roof console I built for the radio.

post-10900-1218494325_thumb.jpg

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the box is funking some inferior non-LR vehicles haveradios that work with the ignition off as long as the keys are in (my mums Audi) i don't know if this is just a new car thing as the most recent lr i've been in lately is my sisters 01 FR

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  • 2 weeks later...

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