Coil Question

Hello all,

A quick question about ignition coils.

I have a 1978 1.1 Golf and according to the Haynes manual this car operates a "ballast" ignition system via a "resistive" wire.

On my other classic car I have a red wire coming to the +ve terminal of the coil (live feed) and a black wire going from the -ve terminal to the distributor (low tension lead). On my Golf, I have a red lead coming to the -ve terminal (live) and a green lead going from the same -ve terminal to the distributor (low tension). I also have a lilac & white and a black wire going to the coil +ve terminal. What is this for? Is this the "ballast" thing that's mentioned in the book?

Forgive my ignorance, but what is a "ballast" system? I would like to renew the coil but notice I can buy either a standard 12V coil or a ballast type and now I'm not sure which one I should be considering.

Any help or advice would be appreciated


Cheers!

Yes the lilac/white is the resistive wire and goes to a relief relay or relay X at the fusebox. Basically it takes the 12v coil supply down to 9v which these coils run at.

Cero, many thanks for the reply….

So does this mean when I buy a new coil I can just buy a standard 12v one or do I have to buy one that is built for a ballast system?

Hi,

Anyone got an answer to my last question before I buy?



Cheers

go for standard mate, built for the ballast system. it's better not to have to change the wiring!!!

Jon.

Hi,

Still a little confused.

You say "go for standard, built for the ballast system" … so do you mean, go for a standard 12V coil or one built for a ballast system?

The 2 types are for sale here:

http://www.classicpartsworld.co.uk/12v_ignition_coil_for_standard_system
http://www.classicpartsworld.co.uk/12v_ignition_coil_for_ballast_system

…except that one is for standard and one is for ballast.

They both look exactly the same to me.

Your best bet is to go to the likes of GSF or Euro Car Parts and get the standard one for your car. It looks like the one you have left a link to for the ballast system is matched with a 1.6 ohm resistor, as far as I know the resistor wire on your car is 0.9 ohms. Cheers.

i mean the standard one for the car, which is the ballast one!!!

Jon.

Thanks everyone for your replies.

I don't really know anything about ballast systems. I thought a 12V coil was a 12V coil and that was that.

The link I put up to a ballast coil does seem to be matched with a 1.6 Ohm resistor. If the resistor wire in my car is 0.9 ohm then I'm assuming this won't be the coil I need.

Still somewhat bemused by it all. Maybe I should try GSF as you say….

The ballast circuit cuts the power to all other electrical parts when turning the engine over on the sarter, to allow the full 12v from battery to be sent to the coil.

Once started the voltage drops to the coil via the ballast circuit.

Ballast wire or ballast resistor?

There are pages in the electrics forum that will help you……

http://www.vwgolfmk1.org.uk/modules.php?name=Forums&file=viewtopic&p=536606&highlight=#536606

http://www.vwgolfmk1.org.uk/modules.php?name=Forums&file=viewtopic&t=8059&postdays=0&postorder=asc&start=0

If that doesn't help this might…

http://www.theminiforum.co.uk/forums/index.php?showtopic=62914

Hi,

These links are all really useful - many thanks!

It looks like you've been having some fun with ballast/non-ballast systems in the past! They're a pretty new thing for me.

So then, as far as I understand - my lilac & white wire to the cil +ve is the ballast resistive wire in use whilst the engine is running to make sure 9v is being delivered to the coil.

The black wire also going to the +ve on the coil is the starter motor bypass which ensures that 12V reaches the coil whilst starting.

The green wire coming from the coil -ve to the condensor is obviously the LT lead.

However, I also have a red wire going to the -ve side of the coil which appears to be another live feed. I thought the lilac/white & black wires handled the live feed to the coil so what is this red wire?

I think I'm getting there….I'm not a bad mechanic but with electrics I'm rubbish…

Cheers

The black wire is the ballast resistor bypass, I think it is taken from the starter motor though. The red wire could be something to do with the oil pressure warning system, that needs to sense 2000 rpm from somewhere, its only a guess.

Cleef said

However, I also have a red wire going to the -ve side of the coil which appears to be another live feed. I thought the lilac/white & black wires handled the live feed to the coil so what is this red wire?

Cheers

This wire could be for a rev counter?

you should have one green for LT from - on coil to dizzy

a red/black wire also to the - on coil…. I think this is the rev counter wire

a black wire on the + side of coil to starter

and the white/lilac wire also on the + side of the coil

The manual says that the 1978 models just have seiries resistive wiring no mention of a resistor being used

A system used in some trailerable sailboats without a weighted fixed keel. Ballast (weight near the bottom of the boat) is needed to keep the boat upright when the wind pushes the sails over. In a water-ballast boat, a chamber in the bottom of the hull fills with water to provide this ballast. This water can then be emptied when the boat is put on a trailer, to make it lighter for easier trailering.

Yes. That's right..