Morris Minor Owners Club

Hi Guys,

Where is the best place to relocate the coil after an alternator conversion?

Regards

John

Somewhere dry where it won't get splashed through the holes in the inner wing.

Here's a photo of mine-on the inner wing.[frame][/frame]
Regards
Declan

I have a bracket which bolts on the back alternator mounting so that the coil stays in the same place.

Mike,
Any chance of a photo of that bracket? I would like to have the coil back where it should be. Whoever fitted the alternator relocated it.
Regards
Declan

Hello all,

personally I think the last place a coil should be is on the engine, hot and vibrating, not the best environment for it.

The inner wing is where it fits easily, and is where I'd recommend.

Alec

Yes - mine stands upright on the inner wing - less vibration and good flow of cooling air.

Thanks,
I'll leave it where it is so.
Declan

[frame][/frame]
The best I could get without unbolting the coil

Thanks Mike
Declan

I NEVER UNDERSTOOD WHY COILS WERE FITTED TO THE BLOCK GETTING VERY HOT INNER WING FOR ME MUCH COOLER..GRANDAD

They fit the coil on the block so that there is a good earth for the spark,

Fitting to the inner wing works fine, but it will transmit more interference (bigger circuit for earth return) and if your earth strap to the engine is poor that will effect how well you run.

thankyou iv learnt something today but still helps the coil to get much hotter but the makers know best thankyou..grandad

Hello Rob,

I can't see that having the coil on the block makes any difference as there is no connection between the coil windings and the case?

Alec

where is the earth path then? is it only via the negative terminal on the coil?

i was thinking that on the block theres a lot of heat transfering onto the coil which allready gets failyhot ..grandad.

Hello Rob,

the earth path is through the distributor; feed in from the ignition to the primary winding which is switched to earth by the distributor, the secondary (HT) winding earths at the spark plugs. If you had an earth connection in the coil it would never function as there will be no flux build and collapse.

Alec

err you can use a coil any way round you want, switching the positive or negative feed, the collapsing field would still result in a spark.

what im asking is where is the 'earth path' for the spark, if I energise a coil and turn it off the other winding must be wired at both ends for it to go somewhere... one end via the HT lead on the coil the other 'earth' side from what connector?

as you say thinking about it the points are linked to earth, so i guess the HT 'earth' must be running back throug the 12v feed through the battery and to the car/engine earth otherwise a a high voltage at the coil with no earth reference would not create a spark gap.

you know I've never though hard about this and always assumed the coil body was important!

The coil works much better the 'right way round' - which is why it is marked +ve and -ve (early ones IGN and CB) - and as Alec has pointed out - the HT earths out through the spark plug - by jumping the gap!

yes... I know but just want to solve for myself where the 'earth' for the HT side of the coil gets back to the block

1: coil is turned on 12v one side, earth via dizzy/contacts the other
2a: when a spark is needed points open in dizzy and HT build up in coil
2b: dizzy directs 'output' to correct spark via rotor arm but...

where is that HT coil tied electrically to the car body
a: does it jump back through the now open points gap to earth? (20k through them so often they would wear out in no time)
b: through the condensor? (I understood that was there to cause the coil to oscilate and so keep the spark going longer)
c: or via the only path left which is the positive side of the coil and via the battery

I know that if your coil is the wrong way round then the 'low' side of the coil winding no long helps with the spark (about 10% loss in spark voltage)