Ballast resistorless coil damage

damage

#1

how much damage did I do to my 1960 TR3A when I have tried to use a coil w/o the required ballast resistor? The coil is too hot to touch after only a few seconds of trying to start the engine (which will not really start) and I have been trying this coil for three months. I had already converted to negative ground, alternator, and Mallory Dual Point ignition, which require the ballast resistor but my propensity For density over looked that small notation. I have had the TR for 34 years and this is really my first big goof.


#2

All coils are 6V whether or not they have an internal ballast resistor. It is impossible to say whether the coil is damaged or not, but I suspect it isn’t. The wire can take well over what you can touch it at. Sparking would be a good sign, but a problem could show up at high speed if a couple turns are shorted. Just as a suggestion, I would recommend an old MSD-5 electronic ignition. I use these on my old flathead boat engines that I can run at a 300 rpm in gear idle for hours without fouling a plug. Above 1,000 rpm there is no advantage. That multiple spark sure gives a great idle with old engines.


#3

Check the position of the stars, kill a chicken and walk three times sunwise around your car chanting: “Oh mighty Prince of Darkness protect your unworthy servant.”


#4

Usually a system with no resistor will burn the points up. Some coil heating is normal but I’d question the too hot too touch part of it.

Why not add a resistor? These can be purchased dirt cheap at car parts houses and they’re dead simple to install. Install it in-line in the power lead to the coil AND make sure you tie from the small starter solenoid wire to the + side of the coil.
This will provide 12 volts in the START position (as it should be) and 6 volts only in the RUN position.


#5

Thanks for the reply and info. I will look into an MSD-5 as it would sure make things easier. Thanks again!


#6

Wow! the points were fried! I will look for an other coil, perhaps with an internal resistor and one that is known to be compatible with the Mallory distributor. I was wondering if any other part of the ignition electris may have suffered damage? Thanks very much for your reply. Very useful.


#7

I see you may have used Lucas “Lords of Darkness - the lights go out when the sun goes down” electrics before? Thanks fro the post, I needed a good chuckle.


#8

You should be able to use an old VW Beetle air-cooled engine ignition coil. Get one for a mid/late 60s/mid 70s model. The earlier VW Beetles were 6 volt systems.
These coils have an internal resistor and if you go this route should be able to plug and play with no problems.


#9

Thanks!


#10

I have a 1974 TR6. So I feel your pain


#11

The Mallory duel-point offers NO advantage in a 4 cylinder engine. The STOCK system will work just fine…

A pointless electronic system offers zero maintenance and so would be an improvement.