TR2/3/3A TR3 Ignition Coil

[martx-5]

Last week, I posted about my buddy Brian's TR3B and it's awakening after 20+ years of hibernation. Well, he's got a new ignition coil that he wants to put on. The old coil terminals are marked with CB and SW. Easy enough, Contact Breaker and SWitch. The new coil is marked with "+" and "-". This car is wired for positive ground. So, which wires go where?? /ubbthreads/images/graemlins/confused.gif

 

[Bugeye58]

The + goes to the points. The points always get the wire that is the same polarity as ground.
Jeff

 

[martx-5]

Thanks Bugeye. That bit of information I will burn into my brain, as I sure I will be confronted with it again.

 

[Geo Hahn]

Be sure that the new coil is not one that requires an external ballast (e.g. a TR6 coil). That kind will work... for a little while... then you'll be replacing the points.

One of the major suppliers will send you the wrong coil if you order the 'push-on' coil they list for the TR3.

From (dim) memory... I think the resistance should be 3 or more ohms... if it is lower than 3 ohms then it will require an external ballast.

 

[martx-5]

Thanks Geo. I will check that out. He did get the new coil from either Moss or TRF, and it does have the push on connectors. I will check the resistance.

This is why I love this place. Real useful info from those that have been there and done that.

 

[Bugeye58]

Roughly 3.6 Ohms for an internally ballasted coil versus about 1.6 for one requiring an external ballast resistor.
Jeff