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TR2/3/3A TR3A coil

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6TTR3A

6TTR3A

Jedi Warrior
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<span style="font-size: 11pt"><span style="color: #003300">[/color]I'm not having any problems with my coil (Lucas HA 12, 45102E,Mfr d. June, 1960), but before I install an electronic ignition, I want to make sure its OK.
I can't find the resistance specs anywhere. Neither my Bentley's or my Haynes makes any mention of coil specs.

I've got 3.2 ohms across the primary, which Petronix says is OK, but I've got 6.7 ohms across the secondary, which no one I've talked to can confirm or deny is OK.
Lucas.UK has not returned my email. (I think it might be too old a model for them.)
Any help would be appreciated.
Frank</span>[color:#006600]</span>
 
Frank, I haven't got the answer, but Lucas UK these days is a company supplying repro components. The original Lucas that would have made your coil went bust long ago.

Viv.
 
6TTR3A said:
<span style="font-size: 11pt"><span style="color: #003300">[/color] but I've got 6.7 ohms across the secondary, which no one I've talked to can confirm or deny is OK.

Frank</span>[color:#006600]</span>
Click to expand...

You have the correct Lucas coil for the car, but 6.7 ohms sounds like a shorted coil. I'm thinking the secondary should be several thousand ohms.

Does this coil produce a healthy spark with the stock points system?

Are you sure you don't have your meter on the ohms times 1000 scale?

I have a few HA-12 coils and will check later today.

T
 
I agree with the above. How is your meter set up and how are you measuring the secondary resistance?
 
<span style="font-size: 11pt"><span style="color: #003300">It's no wonder you're confused. I've got to start proof-reading my posts!! I MEANT 6.7K ohms across the secondary.
My coil is presently on the bench. Primary is measured CB to SW and secondary SW to HT When I removed this coil from the car 5 years ago, it worked fine. The coil I have in there now has too much resistance (4.1 Ohms across the primary) to be compatible with a Petronix </span></span>
 
6TTR3A said:
The coil I have in there now has too much resistance (4.1 Ohms across the primary) to be compatible with a Petronix
Click to expand...
Higher than 3 ohms is not a problem for the Pertronix; and the coil should work just as well with the Pertronix as with points.

But I'd go with the 3 ohm anyway, as the higher primary resistance may present problems with weak spark at high rpm (when there is less time per firing for the inductance to charge).

Secondary resistance is only a very rough indicator of coil condition. Anything between maybe 3K to 15K should be fine.

But that still doesn't prove there isn't a problem. The acid test is to hook it up and run it.
 
From the Pertronix box:
PERTRONIXvolts.jpg
 
6TTR3A said:
<span style="font-size: 11pt"><span style="color: #003300">It's no wonder you're confused. I've got to start proof-reading my posts!! I MEANT 6.7K ohms across the secondary.
My coil is presently on the bench. Primary is measured CB to SW and secondary SW to HT When I removed this coil from the car 5 years ago, it worked fine. The coil I have in there now has too much resistance (4.1 Ohms across the primary) to be compatible with a Petronix </span></span>
Click to expand...

OK That sounds more like a believable value of secondary resistance! :yesnod:

T
 
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