TR2/3/3A coil wire

I want to replace the old wires (low voltage) running from my coil.

What type of wire is that? What gauge? Any special insulation?

Is there a specific part number from Moss, VB, TRF, etc.?

I don't really know the current drawn at 12v, so don't want the replacement to melt!

Thanks.
Tom

For originality you may want to visit Britishwiring.com and buy the correct color coded wire from them. They sell both vinyl and fabric covered wire.

Though I would have suggested 16 AWG wire, it looks like what may have been used by Lucas was a bit lighter, perhaps 18 AWG.

Thanks Doug.

Does it matter whether it's solid or stranded wire?

Tom

The current is low (2-4) amps, so that shouldn't be an issue. The original wire was probably 14 strand (roughly the equivalent of 18 AWG) although 9 strand would do.

The white wire is part of the wiring harness. Looks like Moss has the early white/black wire (ring terminals) as 571-050, the later wire with quick connects is 571-060. I only found one TRF number, 125957, which I think is the later version (but not sure about that).

NutmegCT said:

Does it matter whether it's solid or stranded wire?

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I would suggest stranded, as solid is more apt to break from vibration. Solid wire has basically no place on a car, except to hold the muffler up

Thanks Randall. I prefer coat hangers for mufflers ...

T.

Randall,

Just so I understand you, did you mean that the white wire (from the wiring harness) that goes to the coil "was probably 14 strand . And you say that if replaced, 9 strand would do?

The white/black wire (ring or spade connectors) is available, as you say, from Moss.

Please check me if I'm correct: The white/black wire is the low tension wire (secondary winding) that runs from the coil to the distributor. It is attached to the negative pole of the coil. The white wire (primary winding) runs from the harness to the coil. It is attached to the positive pole of the coil.

NutmegCT said:

Thanks Randall. I prefer coat hangers for mufflers ...

Click to expand...

Wooden, or solid wire?

LexTR3 said:

Just so I understand you, did you mean that the white wire (from the wiring harness) that goes to the coil "was probably 14 strand . And you say that if replaced, 9 strand would do?

Click to expand...

As far as current carrying capacity, yes. But it's probably best to use the heavier wire, just for more mechanical strength.

Please check me if I'm correct: The white/black wire is the low tension wire (secondary winding) that runs from the coil to the distributor.

Click to expand...

Right, although the low tension wire is usually thought of as connected to the primary winding. The secondary winding is the high tension (aka high voltage) winding.

It is attached to the negative pole of the coil.

Click to expand...

Only if you have converted to negative ground. Originally it would have been the positive terminal, which was marked only with "CB" (for contact breaker).

The white wire (primary winding) runs from the harness to the coil.

Click to expand...

Well, technically it runs through the harness back to the fuse block. There is no junction where it enters the harness.

But you've got it basically right.

Randall,

So, then the white and black wire (listed in Moss as low tension wire from the coil to the distributor) is connected to the primary winding in the coil. And the secondary winding, which is attached to the white wire that runs thorough the harness to the fuse block, is the high tension wire.

As I looked at the wiring diagram, it didn't make much sense to me as I had described the wires to you. Your explanation makes it clear (and logical). I had mis-read the diagram.

Many thanks.

I think you may still be confused.

I don't know the best term for the white wire but I think 'high tension' refers to the big ignition wire from the coil to the dizzy (and the spark plug wires).

But possibly no need to ponder that nor think about what is primary and what is secondary -- you've got 2 small wires, the white is unfused power and white/black which goes from the coil to the distributor. As that black tracer suggests -- that wire is 'looking' for a ground which it will find every time the points close. Ergo, it connects to the coil post that is labeled with the ground for whatever polarity you are using.

If you coil is labeled CB (contact breaker) and SW (switch) then the validity of those labels will depend on the polarity as being as original.

George,


In practical terms, all I really am concerned about is that the white wire from the harness is attached to the proper pole, and that the white/black wire is also attached to the proper pole (and, of course, that the wires are in good condition).

My coil is marked "-" and "+". The wire from "-" goes to the distributor; the wire from "+" comes from the harness...

The only time I might actully be concerned about primary winding and secondary winding-- I believe -- would be if I had to bench test the coil.