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MG Midget and Sprite Technical - Ammeter Wires

You might have told me already, but I can't find my last loom thread. Does it matter which thick brown wire (plain brown and brown/white) goes to which gauge terminal?
Nick and Cherry Scoop

Nick,

I'm pretty sure they're a moving coil meter so it does matter which way round it's wired to get the correct indication but you shouldn't harm it with the wrong connection it'll just read the reverse. I can't help with which way to wire it maybe someone else will provide that information.
David Billington

Thanks, David.
Fifty-fifty, then.
Nick and Cherry Scoop

Nick, I hope this doesn't sound patronising but be careful how you wire that thing i.e. it doesn't matter if you wire it the wrong way round but you want the terminals nice and tight as you don't want a wire to come loose and touch metal. The wires should also be well protected from chafing where they pass through the bulkhead.
Bill Bretherton

Bill, nobody could possibly patronise me when it comes to electricity. Thanks for the warning. I did order ammeter wiring from Autosparks, so at least it's neat. But I will look at how I can secure and isolate it.

By the way - anybody who's had a new loom - did it come with all 7 dashboard lamps? Mine's short of rev counter lamp and dual gauge lamp.
Nick and Cherry Scoop

Wasn't the rev counter an optional extra?
Dave O'Neill 2

Ho ho, Dave. I admit there is a double red and white connector in the area, denoting some sort of lighting scheme.
How I wish I had not snipped those two lamp wires on the old loom, especially as they both had bullets at the other end.

You should have told me.
Nick and Cherry Scoop

Your right Nick two lamps are missing. Its the ones with exterior gauge lighting ie the fuel gauge and dual water/oil. They retain clip into the gauge retaining bracket.
Bob Beaumont

Thank you very much, Bob. So it isn't the rev counter lamp missing as I had thought: I need to move the instrument illumination lamps along one, to free the fuel gauge for its old lamp.

I wish I were better at bullets, though. It's hard for an amateur to feel confident about them.
Nick and Cherry Scoop

Nick,

I always solder bullets on to the wire, that way I can be sure that they are both physically and electrically connected properly. You do need a good sized soldering iron ~50w.

Richard
Richard Wale

Do you get some solder into the bullets first, Richard? It sounds awful fiddly.
Nick and Cherry Scoop

yes I solder mine too. I use a tiny flame gun to heat the end of the bullet and then melt the solder when the bullet becomes hot enough. It keeps the heat localised and avoids melting the plastic wire covering
Bob Beaumont

Bob, that sounds as if you need three hands at least. Have you got a cunning method for holding the bullet and holding the wire in position? And doesn't the plastic sheath enter the bullet, and so get melted as you feed the solder in?
Nick and Cherry Scoop

As stated earlier, use decent (50W+) soldering iron. Put bullet on wire (wire clamped vertically in vice perhaps). Put soldering iron on non-wire end of bullet. Feed solder in from wire end of bullet. Takes a few seconds. Only 2 hands needed, but admittedly not so easy if you are working overhead whilst underneath dashboard.
Simon Wood

As to "cunning method for holding bullet" I usually solder crimp type bullets that have a hole in the end. Strip the wire's insulation back far enough so that the conductor protrudes through the end of the bullet and the splay the strands out. Bullet now will not fall off.

Apply a small amount of solder to the iron before placing on the end of the bullet, this helps with conducting the iron's heat to the bullet. Keep iron away from the radial surface of the bullet as you will otherwise get solder deposited which will increase the diameter of the bullet and make it difficualt to insert into the female recepticle.
Simon Wood

Doing my loom, I started off doing the crimp type bullets. I had read somewhere that crimping was better than solder as there is no heat involved to either melt he insulation or weaken the wire strand. It seemed the more "modern" way of doing things. At least that was the message I got.

But I soon found that a crimped bullet distorts sufficiently that it is then really quite difficult to plug it into the bullet connector sleeves. I have reverted to using solder again for the bullets, though for spade type connectors crimping does seem quick and easy and works well.
GuyW

Thanks, All. I've just bought some tiny diameter solder, and I've got plenty of wire and bullets, so here goes.

BTW, I notice that all the bullets in my old loom were soldered, and the new ones crimped, but crimped on four sides, so a proper tool wot I haven't got.
Nick and Cherry Scoop

I've tried three methods, as scribbled below:-
1. Running the solder into the hole in the crown
2. Simon's method, running the solder in at the back end
3. The one I thought of - filling the end of the bullet with solder first, and then (not shown) turning it horizontal to heat up and insert the wire.

Mine was rubbish, and (1) went better than (2). I wasn't sure whether the solder would find its way past the protruding wires, but it sure did, and everything feels solid.

Nick and Cherry Scoop

I'm of the view that crimping is just as good as soldering provided that: (a) you use a proper crimping tool (squashing with a pair of pliers isn't good enough); (b) The connection isn't exposed to water/salt/crud etc.

So crimps are good for anything inside the car but soldering is perhaps a better option for anything that is exposed.

Just my opinion

I'd add that when I worked in the aerospace industry, we used to crimp everthing
Simon Wood

I used to work for a connector manufacturer and we provided connectors for programs like the space shuttle, Voyager, Viking, F16 fighter and many others and they were all crimp connections. So, as Simon says, a properly crimped connection will work well and give long service if properly protected.
Martin

Nick,

Sorry, been away, so delayed reply.

First of all the solder needs to have flux in it.

Both the bullet and wire core strands need to be clean - old wire can get an oxide on the strands that make it difficult/impossible to solder. Equally crimping on oxided wires does not work either!

I strip the wire back so that when the bullet is slipped over the wire, the end of the wire extends out from the bullet by 2-3mm, heat up the bullet with the soldering iron and apply the solder from the bullet hole end.

The solder will flow into the bullet and form a nice smooth end to the bullet and extended wire. Once cooled slightly, trim the wire end back to the bullet with a pair of wire cutters if required.

Richard


Richard Wale

Thank you, Richard. Exactly how it worked for me. I did not think it would be easy with such a small opening, but it seemed that the solder's only desire was to go down that tiny hole.
Nick and Cherry Scoop

I found some of the crimping on the Autosparks loom wasn't all that strong. If you needed to pull the connection out of the sleeve, the blullet was often left behind.

I've struggled solding bullets but now find the best way is this: chop off a short length of solder with integral flux and drop into the bullet. Using pliers to hold the bullet heat with blow torch until the solder is well melted. Having previously prepared the cable end, stuff it in the bullet before the solder resets. I found this gives good, strong results.
Graeme Williams

I will admit to a small extravagance. I have bought a crimper which is wonderful.
Surprised to find that Autosparks' crimps fail, Graeme: the crimps on their bullets are hexagonal, whereas mine are only square.
Nick and Cherry Scoop

Oooooh, which one have you bought?
Dave O'Neill 2

Dave - the only writing on it are 'RIPCA' and 'INSERT'.
It was much too expensive, but it is a joy to use. I will just have to lend it out over the next few years when I hope I shan't need it.
And, I must admit I was boasting when I said mine were square: I have to crimp twice to get it square. But the best two things about this tool are the miniscule muscle required, and the fact that the crown of the bullet is held firmly in shape while you crimp.
Nick and Cherry Scoop

Nick
Does your amp meter have any terminal markings on the back of it like 1-2 or A-B
William Revit

Nothing like that, Willy, when I looked.
The dash is in place now, so I'll look again when my head's in the footwell.
Nick and Cherry Scoop

This thread was discussed between 21/05/2018 and 02/06/2018

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