Ammeter

rsk289 · #1 (**permalink**) 10-16-2014, 04:47 PM

This may be a tricky one, as I'm talking UK market 289 here.
I have the correct early-style Lucas/Smiths ammeter for this car, which unlike the other instruments has a heavy bakelite casing and is a push-fit in the dash, with no provision for a retaining clamp or screws. It has a blue plastic window in the side but I can see no way of mounting or retaining a lamp for instrument illumination. Anybody know how this was done?
Same ammeter as used on the Ace.

db replicas · #2 (**permalink**) 10-17-2014, 02:04 AM

I don't know how it was done but...
You could use a short length of rubber/silicone hose that is a snug fit on the body of the gauge and push this on to help hold the gauge in the dash. then cut a snug hole in the side of this hose to grip the bulb carrier in the same way. (That's if the gauge has a hole for the bulb to poke into) Otherwise another smaller piece of rubber hose superglued to the side hole to hold the bulb carrier.

Well I know what I mean

rsk289 · #3 (**permalink**) 10-17-2014, 06:07 AM

Thanks Dave, I know what you mean!
The problem is that it's an early Smith's gauge, and they didn't have a hole for the bulb - instead, they have a kind of 'window' in the casing just behind the chrome rim at the front for a bulb to shine through. The bulb was held in a clip on the metal bracket that screws on the back of the gauge to hold it in the dash. This style of instrument doesn't have that bracket, it's just a snug push fit.

blue sky · #4 (**permalink**) 10-17-2014, 07:28 AM

Roger
In Ace's and early Cobra's each gauge did not receive a seperate bulb, but actually shared bulbs. All the small gauges for these models should be of the type that are lit externally through slots in the cases. I believe even the 289 Cobra wiring diagram shows this.
AJ

LMH · #5 (**permalink**) 10-17-2014, 08:15 AM

SW gauged cars were lighted the same way. They had a bracket though to hold the gauge in. Could you take the gauge apart and add a couple bolts through the case for a bracket?
I don't know how the lens is held on the Smiths gauges.
Larry

CHANMADD · #6 (**permalink**) 10-17-2014, 08:49 AM

An ammeter is probably best left unattached.They catch fire sometimes , that's why it's bakelite and easy to pull out.It's a defunct gauge.

my427cobra · #7 (**permalink**) 10-17-2014, 09:07 AM

I can't claim to know what the "right" bulb holder is for 289 originality, there are experts here on the forum that can tell you. But having bought many gauges to find the best/right ones, I found there were many styles of bulb holders.
There were of course the bulbs that fit in a hole in the back and bulbs that fit in a tube that protrdues from the back (both these for intenally lit gauges).

And there were a multitude of side window lit gauge bulb holders. One was a ring that encircled the gauge and had a formed tubular tang that held the bulb. One was a formed tubular tang which was held onto the back of the gauge by one of the attachment screws. One was a formed tubular tang which held one or two bulbs attached to a gauge next to it. One was a formed tubular tang attached (soldered, rivetted, screwed to the gauge case.

You could probably go to your local british car shop and ask to sort though their "old stuff" and find one you could attach.

KevinW · #8 (**permalink**) 10-17-2014, 11:09 AM

Quote:

Originally Posted by CHANMADD

An ammeter is probably best left unattached.They catch fire sometimes , that's why it's bakelite and easy to pull out.It's a defunct gauge.

...mainly because the wiring used wasnt up the job. Ammeters require heavy gauge wire that needs to have a current rating over that of the max expected current output of the alternator, and insertion into the loom that does not involve a series connection to the starter. all jmho ofcourse.

my427cobra · #9 (**permalink**) 10-17-2014, 01:12 PM

Wiring is so important for something like an ammeter. Use 10 ga wire. The best you can find with high temp insulation. Do a high quality solder job on the connectors and make sure they are well insulated. I used high quality silicone boots/covers over the connectors.

Rick Parker · #10 (**permalink**) 10-25-2014, 10:29 AM

I think it is prudent to crimp AND solder all connections, Especially on the ammeter. Under high amperage loadsor charging conditions the heat generated COULD melt the solder alone, creating a problem.

rsk289 · #11 (**permalink**) 10-25-2014, 10:51 AM

Well, it's an original BM4 ammeter, so the 'connectors' comprise two molded bakelite tunnels with a brass screw clamping the leads in place. I have soldered the ends of the cables, filed the finished ends to the shape of the slot they have to sit in, and tightened down the brass screws to hold the cables in position. Not a lot more I can do, really! The cables sit down in their slots in the 'tunnels' so there's no protruding metal parts, but silicone boots or anything similar cannot be used in this case - see pic

LMH · #12 (**permalink**) 10-25-2014, 06:11 PM

It's pretty well insulated. I would use it w/o worry.
Pretty bizarre how it's mounted. Just a push-in?
Larry

Rick Parker · #13 (**permalink**) 10-26-2014, 11:26 PM

Consider putting a dab of clear silicone as a preventative measure.

rsk289 · #14 (**permalink**) 10-27-2014, 02:43 AM

Quote:

Originally Posted by LMH

It's pretty well insulated. I would use it w/o worry.
Pretty bizarre how it's mounted. Just a push-in?
Larry

Yes, it pushes in, and there are four small lugs in the casing just behind the rim which clip it into place. Also passively illuminated from a kinda-nearby bulb, shared with the fuel gauge below.

Trouble is, I seem to have some kind of problem with the wiring to allow ammeter and warning light, see other thread, so I may have to bypass this.