Amp Gauge waving like a beauty queen in a parade

Hi, and Welcome!!

Likely loose connections - tighten and problem will likely go away.

Be careful on the nut closest to the gauge; I think spinning the threaded stud may cause internal damage - hold it while tightening the nut.

See this for diagram on how stiffen things up:

(Courtesy of SOBill (Bill Taylor) at: http://www.poca.com/index.php/gallery/?g2_itemId=6585

Larry

Hi Mark,

Welcome to the forum and congratulations on being a Pantera owner!

There is a wealth of information and tech articles that can be found on panteraplace.com.

Here is a link to the stock Pantera ammeter that may be helpful:

http://www.panteraplace.com/page178.htm

Don't hesitate to ask questions on this forum. There are a lot of great people here with excellent knowledge of the Pantera.

John

Looks like Larry posted while I was typing!

Mark, ALL Pantera amp gauges wave to their owners. Mine has been waving to me for 30 years. It's just part of the "charm" and uniqueness of owning a hand-built car. Embrace it! But do make sure you don't have a loose wire too. Normally the needle only waves under a light load. When the headlights or fan motor are on, the needle should be pretty steady. I replaced my electronic voltage regulator with an original type mechanical regulator and that reduced the waving by half.
I guess you haven't noticed the rear view mirror vibrating yet. And if you have a 72 Pre-L like me, a couple of the dash lights reflect off the windshield at night and stare back at you like two little eyes. But I wouldn't have it any other way!

Mark,
If the bouncing needle bothers you, there is an ammeter available that's an exact replica of our Veglia ammeter, but has different internals. It's rated at 100 amps and has an internal shunt, so it doesn't wave at you. The first time I saw it was in a Hall Pantera catalog but I bought mine from Precision Proformance.

Don't forget to disconnect the battery when working on or around the ammeter.

Just get rid of it and replace it with a volt meter.

Hi,

After installing the Kirk Evans bulkhead reduction kit's GM 10-SI (12-SI?) alternator, my ammeter has calmed. It still shows current draw from fan, headlights, directionals, ect, but no longer slams from side to side while on the edge of charge/discharge. The GM alternator has an internal regulator, but includes an external sense lead.

Hi,

I am just checking out the ammeter bouncing thing on #5891. Have already installed a new alternator and regulator during my engine rebuild one year ago. the needle kept on bouncing. I have also swapped the ammeter with another one from a friend´s pantera. no success, also this one bounces in #5891. Have checked the wires; all ok.

Nice waving needle on you tube? Look here: https://www.youtube.com/watch?v=Kws7IUvvoN0
or here: https://www.youtube.com/watch?v=IcW9g6aphTU

So next step would be to install a shunt resistor.
Do you have any experiences which type of shunt should be used? My alternator and regulator are similar to stock types.

Thks all!!
Wolfgang

Wolfgang, the 'shunt' is nothing more than a direct connection across the amp gauge terminals ALONG with the stock wiring hookup. So the current splits and goes thru BOTH the meter and around it. This reduces the needle waving but degrades the accuracy. In the case of the Pantera, stock accuracy is not great anyway. The gauge basically tells you the alt is putting out current; how much is another issue.

My shunt is a simple piece of 0.060" brass shim about 1/4" wide x as long as is needed to stretch from gauge post to gauge post. The larger the shunt's surface area, the less current goes thru the meter. Its a good idea to use shrink wrap or other insulation on your shunt since its carrying a LOT or current!

Bosswrench,
thks a lot for your explanations! Tonight I have tried a third ammeter without any success. I also installed two 2mm wires between the posts of the gauge which didn´t make the whole thing much better. I`ll try the brass shunt and report how it works!
Thks again, Wolfgang

Try a 10 ohm or 27 ohm 1/2 watt resistor across the two terminals. I would also add an 80 amp in line fuse for added protection. All you really want the thing to do is lean to positive or negative to indicate charge or no charge. The amount is not that important. Resistor values will vary. I don't remember what mine was. it might have been 47 ohm. but a few from radio shack should cover it.

RRS1, sorry about my bad english but did I understand you correctly? You recommend to put in a 27ohm resistor across the terminals and protect this solution with a 80amp in line fuse?
Correct?

The resistor will take out the waving, the fuse is just protection in case you ever have a short in the cable. All the charge current passes through the meter. It can melt down and maybe cause other damage, so just safety.

RRS1, thks a lot for your recommendation. I fully understand the purpose of the fuse. Concerning the resistor: Do I have to take a special one because of the massive current or can I just live with a standard resistor?

quote:

special one because of the massive current or can I just live with

Wolfgang -

The most current you can get across the resistor is I = V/R = 12 / 27 = ~ .3333 Amp

The power in the resistor is P = I*V = 4 Watts

So you should try and find a 5 Watt Resistor. This will probably be pretty big.

Good Luck

Rocky

Rocky,
thks a lot. I`ll check that!! Hopefully I can improve these symptoms!
Wolfgang

quote:

Originally posted by Rocky:

quote:

special one because of the massive current or can I just live with

Wolfgang -

The most current you can get across the resistor is I = V/R = 12 / 27 = ~ .3333 Amp

The power in the resistor is P = I*V = 4 Watts

So you should try and find a 5 Watt Resistor. This will probably be pretty big.

Good Luck

Rocky

That would be true if the resistor was sharing the load, but it's not. All the current passes through the internal shunt. The resistor only serves to change the behavior of the movement.

You're right. The voltage drop across the resistor and shunt in parallel will be very low.

Rocky