Morris Minor Owners Club

I had an interesting breakdown yesterday.
I was ambling along in my Traveller in rush hour traffic when the engine stalled. A few churns on the starter motor showed that it wasn't going to fire so I looked under the bonnet to find a pool of oil down the side of the engine and the innards of the coil blown out. I always wondered what the inside of a coil looks like, now I know why the call it a coil!!
Could it have overheated? The innards of the coil were still too hot to touch 10 mins later.
There was I, parked in the inside traffic lane with the hazards flashing and the back doors open. It's amazing how many cars come right up to you then find that they haven't got room to move into the outside lane.

I had this happen. T'wasn't in traffic though. I'd left the ignition on without the engine running. It gave me a nasty shock. Seconds before I was leaning right over it

Indeed it must have overheated at some point in it's life ! Or -was rated for 6 or 9 volts, and was being run on 12 - which is actually nearer 14 !!

It was the correct coil for the car, a proper Lxxxx unit and has been on the car for some time

And did it show any signs of distress beforehand - leaking oil, anything like that ?

No warning at all, it just went, fortunately after I had left the motorway

Well oil be!

Well oil be!

Broken?

Not come across that before Mike, was the coil mounted in the normal position.

On the bracket over the alternator. As it only has one clamp bolt I make sure that the pinch bolt and clamp bolt are both tight. I once had the pinch bolt work loose and the coil slid back out of the mounting bracket and shorted out on the engine block. By the time the engine had cut out and I had stopped on the hard shoulder there were some nice little flames coming from the wiring loom. Thanks to the gallon of water I carry, not too much damage was done

I wonder if there could be any electrical interference between alternator and coil when fitted so close to each other ? Seems highly unlikey - but this 'exploding' coil is a rare event indeed! My coil is fitted on the inner wing- well away from extra heat and well away from other electric devices. May be worth considering Mike !

but this 'exploding' coil is a rare event indeed!

not really that rare - far less chance of winning the lottery.

If they loose a bit of oil, then they will overheat. During overheating the coil insulation brakes down and they draw a lot more current - making them even hotter...

At some point the oil boils making one heck of a lot of pressure.

pop




Or if you're lucky the coil overeats and then goes open circuit. The engine stops and the coil cools down.

Yes - but there was seemingly no loss of oil before the big bang.
Has anyone else on here every suffered an exploding coil ??
I believe it is a very rare event! Whereas almost every saturday someone wins the Lottery! Ergo - exploding coil is much rarer event than lottery win !!

Maybe it doesn't get so much publicity!!
Now that the coil has cooled down I shall take a photo of it, for the benfit of those like me who have never seen the inside.
I am having a heck of a job buying a coil "off the shelf", eventually gave in and ordered one for tomorrow to replace the one I pinched off the MM which is awaiting an engine removal, when I get through the never ending task list the other half keeps giving me.

You should carry a spare coil anyway! That way - nothing will go wrong with the one on the car.

bmcecosse wrote:You should carry a spare coil anyway! That way - nothing will go wrong with the one on the car.

Ha! So true, I've been lugging a spare coil around for years. It's the threat of replacement, keeps them in line.

So working on that theory the best idea would be to tow a spare car round with you and so never break down :):):)

would have drastic effects on the MPG tho

bmcecosse wrote:You should carry a spare coil anyway! That way - nothing will go wrong with the one on the car.

Good job I was carrying a spare when mine died on the way down to the National this year. The one that died was Lucas branded and had only been on the car for a couple of weeks! Here's what I found when I opened it up:

<br><br>

This is what is inside a coil, after it has blown apart.<br><br>

Both interesting pictures! A good reason to keep the coil mounted where it won't suffer lots of vibration. ie NOT on the engine - bolted to the inner wing works well for my car.
Are going to solder that one up Alex - and refill with oil ??