Ballast resistor ignition coil or not?

[grahambell]

Looking at refreshing the ignition system on my 1999 Chimaera and apparently some Chims have ballast resistor ignition coils and some don't, so the question is, how do you tell which type you have?

I see that some ignition coils for TVRs have a black 'collar' around the top and some don't (mine doesn't).

Is it that simple, or is the ballast resistor tucked away somewhere out of plain sight?

[phillpot]

I didn't think a ballast resistor was used on any Chimaeras or Griffiths, they died out with points & condensers?

This will do the job . . . . . . https://www.ebay.co.uk/itm/153312302027?hash=item2...

Edited by phillpot on Thursday 5th August 11:17

[pete275]

You could also go with the Viper dry coil

https://simonbbc.com/Viper-Dry-Ignition-Coil-Sport...

Had them on both of my Chims

[NMNeil]

grahambell said:

Looking at refreshing the ignition system on my 1999 Chimaera and apparently some Chims have ballast resistor ignition coils and some don't, so the question is, how do you tell which type you have?

I see that some ignition coils for TVRs have a black 'collar' around the top and some don't (mine doesn't).

Is it that simple, or is the ballast resistor tucked away somewhere out of plain sight?

Measure the resistance of the primary winding's. If it's about 3 ohms, it doesn't need a ballast resistor, about 1 to 2 ohms, it does.

[spitfire4v8]

The viper coil mentioned above says 0.7ohm in the spec .. is that an issue ? Can you / how do you even measure the resistance of something that is constantly being switched on and off ?

penelopestopit ?

[grahambell]

Thanks for the replies chaps. Looking like Chims never had ballast resistor.

[pete275]

Viper coil should be fine

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[grahambell]

Hi Pete,

Yes, was looking at the Viper coil. Common thing is 'get Bosch for the quality' but looks like the Bosch coils are now made in Brazil, so maybe not what they used to be.

[spitfire4v8]

On the dyno if I have a car with a high rev misfire, pound to a penny it's the shiny new bosch coil the owner has just fitted .. what's changed I don;t know but it has happened way too many times for it to be just coincidence.

[blitzracing]

Dont forget dropping the primary resistance will increase the current the amp has to switch, and at these low resistances dropping the odd ohm has a massive effect. The physical size of the amp does not fill me with confidence it could switch say 10 amps for extended periods. At least I'd be carring a spare in my boot.

[Polly Grigora]

spitfire4v8 said:

The viper coil mentioned above says 0.7ohm in the spec .. is that an issue ? Can you / how do you even measure the resistance of something that is constantly being switched on and off ?

penelopestopit ?

Most definitely is an issue

How can a standard ignition amplifier drive a circuit that draws 20 amps?