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TR2/3/3A On TR3A what gauge wire from fuse box to coil?

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TuffTR250

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On my TR3A some previous owner stretched a dedicated wire from the fuse box to the coil. It appears to be about 16 gauge. What gauge wire should be used for that? Thanks!

For now I will use a dedicated wire but will try to figure out why a dedicated wire outside the wiring harness was put in.
Regards,
Bob
 
16 AWG should be adequate. Most likely the wire that runs inside the harness is broken; probably somewhere near the coil as that section takes a bit of a beating.
 
Bob, make sure it only works with the key, just a thought. That's how a lot of these cars were stolen back in the day, a alligator clip from the battery to the coil, push start, and away you go. Maybe I should not have told this. The later ones with locking steering system were not as pron to thief.

Wayne
 
trrdster2000 said:
The later ones with locking steering system were not as pron to thief.
Click to expand...
But only slightly less so. Generally a good, hard yank on the wheel would break the lock bolt; or if that didn't work, a small slide hammer would pop the lock cylinder out in a second. A zip gun will turn it without damage (but is risky to carry around).

"Gone in 60 seconds" was just a catchy name; the average car thief only takes about 10 seconds. Locks only keep honest people honest.
 
TR3driver said:
But only slightly less so. Generally a good, hard yank on the wheel would break the lock bolt; or if that didn't work, a small slide hammer would pop the lock cylinder out in a second. A zip gun will turn it without damage (but is risky to carry around).

"Gone in 60 seconds" was just a catchy name; the average car thief only takes about 10 seconds. Locks only keep honest people honest.
Click to expand...

Yep, when my TR4A was stolen, the thief just jammed a big screwdriver into the ignition and turned. Fortunately my car fought back, for one there wasn't any coolant in the block (the water pump was out for replacement), and if that wasn't enough, one of the rubber steering couplers came apart. Probably some delinquent out there still cursing those unreliable British cars!
 
One summer I was cruising along in my TR3A and the speedometer suddenly zoomed up to 100mph and the car went dead! I coasted to the side of road and popped the hood. It seems that the coil wire had been riding against the speedo cable and burned thru the insulation on the wire causing the shut down. Fortunately I had my full Lucas emergency kit in the boot and I was back on the road after splicing in a new piece of wire. :smile:
 
My local wire supplier offers the following:

Ref 14. 14/0.30mm, 1mm[SUP]2[/SUP], 8.75amp.
ÂŁ0.37 per metre. ÂŁ12.26 per 50 metre reel.
Typical applications. Side & tail lights, alarms, reversing & rear fog lamps,
electric aerial, horns general wiring.

This is pretty much what was used originally.

Al.
 
Wayne, I had the same thought after I asked the question, i.e. should the wire be going through the ignition switch. I looked for a white wire (per wiring diagram) coming out of the wiring harness up by the switch but didn't see one. I'll have to crawl under the dash and look some more.

Randall, I do see a white wiring coming out of the wiring harness right inside the engine compartment that looks like it was accidently cut since it has a sloped cut. I found it when I unwrapped a bunch of really sticky old electrical tape from the harness. The cut wire was not terminated just wrapped in with the other wires. I'm going try to do a continuity test on that cut wire, but have to find the other end yet.

Alan, not sure what gauge wire you are recommending, please decode for me. Thanks!

Thanks for the responses!
Regards,
Bob
 
Has 14 strands of wire each 0.3mm in diameter. You might have 12 thou strands in the US.

Alternatively the overall area is 1 sq mm. This is how Germans do wire specs.

Definitely MUST go through the ignition switch. The clue is in the name. If wired direct it will flatten the battery.

Al.
 
I agree that the coil wire "should" go through the ignition switch, however, the TR3A/TR3B wiring diagram shows a white wire direct from the A3 location on the fuse box over to the ignition coil. It does not show any wires from the switch to the coil. The wiring diagram I'm using comes from www.advanceautowire.com. Is that diagram from them that I'm using incorrect?
Regards,
Bob
 
Bob, long story short, we are taking about wiring it the side of the fuse box that is controlled by the switch to be hot and dead when the switch is off and fuse controlled.

Wayne
 
TuffTR250 said:
I agree that the coil wire "should" go through the ignition switch, however, the TR3A/TR3B wiring diagram shows a white wire direct from the A3 location on the fuse box over to the ignition coil. It does not show any wires from the switch to the coil. The wiring diagram I'm using comes from www.advanceautowire.com. Is that diagram from them that I'm using incorrect?
Click to expand...
The diagram is fine, the A3 terminal on the fuse block gets it's power through the ignition switch.

It doesn't really matter if the coil wire goes to A3 or directly to the switch; except that then there would be 4 white wires meeting at the switch and it will be difficult to get all of them into the clamp. Triumph arranged things a bit differently than you might expect, to avoid having any junctions within the harness (and no more than the connection points could handle).

18 AWG (American Wire Gauge) would be the closest equivalent to the 14 strand wire that Al mentioned. You could use that too. But it certainly won't hurt anything to go slightly larger (16 AWG is about 1.7 sq mm).
 
Ah, thanks Wayne and Randall! I did not realize that the ignition switch controlled the A3 fuse connection. Although I think the added bright yellowwire on mine may be 16 gauge I think I'll change it to 16 gauge white wire so it is consistent with the wiring diagram. Thanks for the information!!
Regards,
Bob
 
TuffTR250 said:
...The wiring diagram I'm using comes from www.advanceautowire.com. Is that diagram from them that I'm using incorrect?
Click to expand...

Yes, it appears to be incorrect.

https://www.advanceautowire.com/tr24a.pdf

Looking at the 3A page... you'll see a 'W' to the right of the ignition switch with no wire there. Further right you'll see a 'wire from nowhere' going down to the fuse block. There is a line missing that should represent that 'wire from nowhere' connecting to the fuse block -- this is how the coil (unfused) and all the green circuits (fused) get their power.

If there is no wire from your ignition switch to the fuse block then the fuse block must be getting power some other (incorrect) way.
 
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Geo, when I look at the 3A page from the Advance link you supplied, I see the "W" wire on the right side of the ignition switch going to the fuse block at A3.
 
That's odd -- seems to depend on what magnification one uses. At 100% and 150% (on my computer anyway) the wire disappears, yet at other magnifications it shows.
 
Geo Hahn said:
That's odd -- seems to depend on what magnification one uses. At 100% and 150% (on my computer anyway) the wire disappears, yet at other magnifications it shows.
Click to expand...
Wow, that is odd! Not only is the wire gone completely at 100%, but at 125% on my computer there are a bunch of lines that disappear. The other drawings are affected as well, though not necessarily the white wire. The body of the wire is still shown (when it isn't white), but one or both of the outline lines are missing.
 
Interesting. I zoomed from 45% to 190% and nothing disappeared...Go figure. Of course, the white wires showed "gray" at the lower percentage, as I guess it was mixing with the dark outline. They don't show up with an outlined white center until about 65%.

Maybe it has something to do with the version of Acrobat reader that's being used.
 
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