Dizzy Wiring

An alchemy of sparks, copper wire and earth

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Evil Elsie
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Dizzy Wiring

Post by Evil Elsie »

Hey Folks,
                I've just bought a Powersparks Dizzy, Coil and Lead set and have a question...

A Green and a Black wire from the Ignition Amp to the Coil - no problem.
The other Green and Black from 'somewhere' to the Coil - no problem.
My problem is that there's three wires going to the plug on the existing Dizzy but my new one just has the standard Live and Neutral.

How do I make three go into two..?? Do I siamese two together or is one now redundant..??

Any thoughts gratefully received,

Dave.
 
'90 Suzuki GSXR 1100L
'87 VW T25 1.9DG (or maybe not..)
'80 Yamaha RD 350LC
'74 Landrover Lightweight
:run

 

davidoft1
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Re: Dizzy Wiring

Post by davidoft1 »

You wire yours directly to the coil and lose the rest of the wiring , ignition amplifier etc

Be careful as live on the coil is black
the red wire on your distributor is live

the other distributor wire is black and go to the negative of the coil , usually has a green on the coil

Evil Elsie
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Re: Dizzy Wiring

Post by Evil Elsie »

That's brilliant - thank you.

So the Live wires on the existing coil were the Black ones..??
That would have caught me out - huge thanks for the warning....

Cheers, Dave
'90 Suzuki GSXR 1100L
'87 VW T25 1.9DG (or maybe not..)
'80 Yamaha RD 350LC
'74 Landrover Lightweight
:run

 

davidoft1
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Re: Dizzy Wiring

Post by davidoft1 »

Evil Elsie wrote: 13 Jul 2021, 17:05 That's brilliant - thank you.

So the Live wires on the existing coil were the Black ones..??
That would have caught me out - huge thanks for the warning....

Cheers, Dave

yeah catches most folks  out 

Evil Elsie
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Re: Dizzy Wiring

Post by Evil Elsie »

Ooo.!!
Another one - out of the four existing wires that go to the original Coil (2x Black & 2x Green) one of the Black 'lives' (sorry, mind blown by that) must still need to go to the Coil...??
The one from the Ignition Amp or the other one from 'somewhere unseen'..??

Cheers, Dave.
'90 Suzuki GSXR 1100L
'87 VW T25 1.9DG (or maybe not..)
'80 Yamaha RD 350LC
'74 Landrover Lightweight
:run

 

davidoft1
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Re: Dizzy Wiring

Post by davidoft1 »

Evil Elsie wrote: 13 Jul 2021, 17:14 Ooo.!!
Another one - out of the four existing wires that go to the original Coil (2x Black & 2x Green) one of the Black 'lives' (sorry, mind blown by that) must still need to go to the Coil...??
The one from the Ignition Amp or the other one from 'somewhere unseen'..??

Cheers, Dave.

yes the one from the main loom, probably comes with from the wiring on the carbs too , swithc the ignition on and see which wire is live and goes dead with the igntion off

Evil Elsie
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Re: Dizzy Wiring

Post by Evil Elsie »

Lovely - thanks again.

I'm equally embarrassed and amused by the fact that I've owned this van for four weeks now and I've only just found out the the Black wires are 'Live' and the Green wires are 'Earth'.
Your reply has been the most enlightening and fire-ball saving post ever made.... :D

Cheers, Dave.
'90 Suzuki GSXR 1100L
'87 VW T25 1.9DG (or maybe not..)
'80 Yamaha RD 350LC
'74 Landrover Lightweight
:run

 

davidoft1
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Re: Dizzy Wiring

Post by davidoft1 »

Evil Elsie wrote: 13 Jul 2021, 17:25 Lovely - thanks again.

I'm equally embarrassed and amused by the fact that I've owned this van for four weeks now and I've only just found out the the Black wires are 'Live' and the Green wires are 'Earth'.
Your reply has been the most enlightening and fire-ball saving post ever made.... :D

Cheers, Dave.

welllll, green is only negative on the ignition system, for everything else brown is earth 

Evil Elsie
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Re: Dizzy Wiring

Post by Evil Elsie »

Really..??
Why in the name of all that is small and furry would they do that..???????
That's just cruel.

I'm going for a lie down......


Your warnings are duly noted and very much appreciated.

Cheers, Dave
'90 Suzuki GSXR 1100L
'87 VW T25 1.9DG (or maybe not..)
'80 Yamaha RD 350LC
'74 Landrover Lightweight
:run

 

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Robsey
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Re: Dizzy Wiring

Post by Robsey »

Hmm - I am not sure that I would say that the green is a true earth. It does not go direct to an earth point. It is a switched ground. It is the negative side of the coil.

It is a switched "ground" controlled by the ignition system.
Hall unit for electronic ignition systems and "points and condensor" for early non-electronic systems.
The earth point is the distributor body or it's earth braid to the engine block. (Dependent upon exact vehicle).

The green output also provides the rpm pulses to the tachometer on petrol vehicles.

Sorry to sound pedantic, but that is the reason why it is not brown.

Red = battery live (before the switch)
Black = ignition controlled live.
Brown = direct connection to the body / chassis / ground / earth.
1983 Tin Top with a poorly DF and 4 speed DT box.
1987 Electrics and a DJ engine.
Maybe one day I might get it finished

Evil Elsie
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Re: Dizzy Wiring

Post by Evil Elsie »

Er, ok - that actually makes sense and is probably a better way of doing it once you 'get your head around it'.
I'm going to have to write it down and keep it in the van somewhere.

Thanks for the clarification.

You state in your post that the Tacho for a Petrol engine should be connected to the Green (-ve) side of the coil..??
I was just about to rig one up and was going to connect it to the (+ve) side of the coil (with it's crazy Black wires).

So it's the Green wired, Negative side of Coil for Tacho signal..??

Cheers, Dave.
'90 Suzuki GSXR 1100L
'87 VW T25 1.9DG (or maybe not..)
'80 Yamaha RD 350LC
'74 Landrover Lightweight
:run

 

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Robsey
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Re: Dizzy Wiring

Post by Robsey »

That is correct - green to tacho.

The reason is:-
The black is an ignition live feed.
As long as the ignition key is in the on / run position, there will be a constant steady battery voltage there.

Turn the key to the off position or remove the key, and there is no voltage there.

That was the easy bit.
--------------------------------

The green is a bit more complicated.

There is some electronics within the distributor - usually it is what is called the hall sensor.

Old world cars used a mechanical switch called points or contact breaker to act as a switch.
But I won't go into the complexities as most T25s should be electronic ignition.

As the engine spins, a central shaft within the distributor spins a disc with 4 vanes on it. As each vane passes the hall sensor, it closes the circuit for a brief period, and allows a pulse of electricity to go from the coil to ground via the distributor body.

These pulses are what provide the ignition pulse to the electronic control units and the rpm signal for the tachometer.

So - connecting to the black would be like connecting directly to full voltage and would cause the tacho needle to bang hard over to the right, probably destroying it.

So green is the one you want for tacho signal.
Last edited by Robsey on 14 Jul 2021, 07:40, edited 1 time in total.
1983 Tin Top with a poorly DF and 4 speed DT box.
1987 Electrics and a DJ engine.
Maybe one day I might get it finished

Evil Elsie
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Posts: 23
Joined: 26 Jun 2021, 09:52
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Re: Dizzy Wiring

Post by Evil Elsie »

That's superb.
Thank you very much for the explanation - and taking the time to explain.

All responses are really appreciated..

Cheers, Dave.
'90 Suzuki GSXR 1100L
'87 VW T25 1.9DG (or maybe not..)
'80 Yamaha RD 350LC
'74 Landrover Lightweight
:run

 

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