ignition coil gets hot

[acgibbs]

Hi,
I am having a great difficulty starting my 1969 Morris Minor 1000. When it does start it runs very rough and the coil is getting very hot. I am thinking of changing the shark plugs. What type of NGK plugs should I use? Any help would be appreciated.
Thanks,
Andrew

[Pyoor_Kate]

I'd be thinking of changing the coil myself

[bmcecosse]

Something fishy here ! Coil will get hot if the engine is left with the ignition ON and the points closed - it's passing current !! Check the points gap, and when did it last have a new condenser ? Clean all the other ignition components - rotor arm/dizzy cap/HT leads - in fact these all cost so little it really is better to just renew them all every few years. Just use N9Y champions if it's a standard engine, or go to N7Y or even N6Y if highly modified.if

[57traveller]

Something fishy here ! f

Does that refer to the "shark plugs"? - Sorry.

[Cam]

NGK BP6E or BP6ES

But I'd clean everything up, check all connections and think about a new coil first.

[bmcecosse]

Coils very rarely fail - and if the do - they don't get hot ! The fact it is hot tells me it is passing current ok. Get a new one if you want (along with all the other new ignition gubbins) - but i doubt it is the reason the car is not starting at the moment.

[Cam]

The coil can go partial short inside (insulation breaks and coil turns come into contact with each other). It's not common but has happened before. This causes excessive current drain and poor output. Perhaps getting a spare coil is a good idea anyway and you can try swapping it over and trying the new one.

[bmcecosse]

Once happened to me Cam - when the casing cracked and leaked all the oil out - on an 'all night' rally too. Fortunately I had a spare in the car !

[Onne]

oil in coil? Or coily bits falling out instead of oily bits

[Pyoor_Kate]

Err, I've had three coils on my car, all from various mm suppliers, all of whom have agreed that modern coils seem to fail with shocking regularity.

On all occasions they've got very hot... same as the ones on the zed, but they fail from being shaken to pieces.

[maurice]

well i've had between 4 and five coils in the last year. all modern ones except for the current one. they all overheated and when i took one of them apart i saw that one of the wires going to the spade terminal was burnt through. these were all budget modern coils from halfords or other such places. an old-style oil-filled one (filled completely) from commercial ignition seems to be alright, but then i haven't had it that long and it still gets pretty hot. also make sure the two wires are not swapped around as the car will still run but not as efficiently. however i am not certain this will cause it to burn out. anyway i hate coils and wish they weren't needed!
good luck

[Peetee]

modern coils seem to fail with shocking regularity.

Groan!

all modern ones except for the current one

Double groan!

Scuse my ignorance but is this heat problem recalling the old ballasted/non-ballated debate perhaps?

[Pyoor_Kate]

I don't think so; they are coils from minor specialists (at least the ones on my car were) - not ones from random-car-parts-suppliers.

[bmcecosse]

I just use an old standard Lucas coil - but I have it mounted low down on the inner wing, not on the engine. So it gets lots of cool air - and no heat transfer from the engine. Can't say I have noticed it anything more than slightly warm - but the car should NOT be left with the ignition on, and the engine not running.

[forbesg]

Just out of curiousity, what's the expected life of a coil? I've still got the original in the `54.

[Cam]

Well, they can last a very long time, but it all depends really.

My mate used to change his coil every service! But I have never changed one unless it's developed a fault.