Dissection and Study of a Mopar Ammeter

[Photon440]

Just as a curio item, when I took apart my 1970 instrument panel, the little stamped sheetmetal faces of the oil, temp and fuel gauges were stamped steel. The similar looking ALT gauge was stamped aluminum. Something to do with magnetic fields?

 

[Nacho-RT74]

you see it peg 40 and you turn on the headlights and that generally corrects things. If not shut the bugger off.

actually thats true, it helps to reduce the load going to the batt through the ammeter. But your problem was not the ammeter as yourself admited, so is not fair blame it and discard it on any situation and even without problems yet because that

Looks like amp meter is the next oil thread here..

it began maybe 12 years ago on my side LOL. Dunno on this board, but on Moparts and maybe less on dodgecharger.com

 

[dadsbee]

I know it wasn't the amp meters fault and it generally never is, it's a voltage regulator stuck that usually causes a wiring fire after it pegs full alternator output and you sit back and do nothing to use some of that output.

 

[Nacho-RT74]

Just as a curio item, when I took apart my 1970 instrument panel, the little stamped sheetmetal faces of the oil, temp and fuel gauges were stamped steel. The similar looking ALT gauge was stamped aluminum. Something to do with magnetic fields?

It can be very well that, since the ammeters got a magnet as part of the assembly, so the steel could get enlarged the magnetic field

 

[Nacho-RT74]

They are effectively the same gauge, just different face plates. The operation is the same no matter which one you use....in case anyone gets stuck for one of the other.

they are in fact the same width between studs SO, you could upgrade an old amm with a new one with a wider ammeter scale if matches the inners disposition and needle indexing with your old one

for example:

71/74 standard cluster maybe for fleet cars

( there are also 80 amps of these )

or




from some mid 60s truck

but STILL would try to keep it safe from any unnecesary load, because even the scale is bigger, the "weak" points are the same between studs and brass shunt being installed by pressure. Difference is just magnet calibration to move the needle.

 

[Hemirunner]

I’ll never understand the logic behind an ammeter in the system as the entire system load goes through it.

 

[Nacho-RT74]

not the entire system load, but the load coming in and out from batt... read the thread with the poll

 

[72RoadrunnerGTX]

I’ll never understand the logic behind an ammeter in the system as the entire system load goes through it.

I’ll never understand where this kind of misinformation comes from. If you want to understand this charging system as originally designed, read some of the numerous threads here that contain the facts.

 

[383man]

They beat up from loose connections and not having a fusible link. I hear from people all the time how I goona burn up my car but get no response when I ask who they know personally that had there car actually burn down from a failed device.

They do have a fusible link. Usually is right off the starter relay stud on the hot feed to it. Ron

 

[383man]

not the entire system load, but the load coming in and out from batt... read the thread with the poll

I think many people feel it does take the full load because when you look at the wiring some just see it and don't think about when the car is running. If you just turn the key on and anything else without starting the car then all the load goes through the ammeter. But I think some forget to think about how it is with the car running and the alt feeding everything and only the charge into the battery goes though the ammeter then when the car is running as long as the charging system is working. I have even caught myself saying …..oh yea all power goes through the ammeter before thinking about what I just said. Ron

 

[rumblefish360]

They do have a fusible link. Usually is right off the starter relay stud on the hot feed to it. Ron

Yes, I know and said that earlier... (*I Think* could have been another thread.) On my A bodies, and some other cars, it is located behind the power booster or just to the left near the bulk head. I guess it depends on year to year, model to model.

 

[MoparLeo]

So the bottom line is ????? Ammeters never cause underdash fires ? Fake News ? The factories discontinued using them for no good reason ? 50 year old electrical systems never fail. Some people have all the luck and some don't ? Electrical items are good until they are bad. "But the light bulb worked the last time I turned it on." I don't understand...
Most people are not proficient in electrical systems or theory. Need to keep info to the lowest common denominator to be safe.

 

[rumblefish360]

So the bottom line is ????? Ammeters never cause underhood fires ? Fake News ? The factories discontinued using them for no good reason?

Oh! It can happen, I have no doubt, I just never met anyone that actually had a fire due to a bad amp meter. But everybody seems to know someone.... or at least someone’s second wife’s third removed adopted Cousin.

50 year old electrical systems never fail. Some people have all the luck and some don't ? Electrical items are good until they are bad. "But the light bulb worked the last time I turned it on." I don't understand...

This I don’t understand. Sarcasm?

 

[383man]

Yes, I know and said that earlier... (*I Think* could have been another thread.) On my A bodies, and some other cars, it is located behind the power booster or just to the left near the bulk head. I guess it depends on year to year, model to model.

Sorry as I guess I miss understood you. Take care. Ron

 

[rumblefish360]

Never a problem Ron!

 

[Hemirunner]

I’ll never understand where this kind of misinformation comes from. If you want to understand this charging system as originally designed, read some of the numerous threads here that contain the facts.

So if you have a battery failure or an alternator failure, then full system load is running through the Ammeter? I’m no sparky, but assuming you leave it as factory wired, you’ll be fine, but once you add anything on, you’re risking potential disaster. If you add an aftermarket ignition system and run it off the battery, it’s passing more charging load back through the ammeter.
It’s the same with the crap design of running multiple high load circuits through the ignition switch. It’s asking for trouble. You’ll be hard pressed to find one of these cars without melted firewall bulkheads or ignition switch connectors unless it’s a well preserved stocker.

 

[Nacho-RT74]

If you have an alt or batt failure and you still keep running the car no matter if the ammeter read or not the full load, you have the responsibility on don’t keep running the car under a major failure and don’t blame the ammeter.

And in any case if you still decide to run under a major failure, the ammeter will let you know what you can or not make to keep the system safe.

if your engine overheats, won’t be the temp gauge or sender fault. Except if they get a wrong reading for some damage on gauge, wire or sender.

if you decide to add anything on the stock system will be your responsability to make it right, and don’t blame the ammeter anymore.

Run an ignition system ( or ANYTHING) straight to the batt is one of the wrong procedures for example. And then don’t blame the ammeter!

( actually ignition systems doesn’t add excessive loads even sourcing them from battery anyway )

 

[Hemirunner]

If you have an alt or batt failure and you still keep running the car no matter if the ammeter read or not the full load, you have the responsibility on don’t keep running the car under a major failure and don’t blame the ammeter

And in any case if you still decide to run under a major failure, the ammeter will let you know what you can or not make to keep the system safe.

if you decide to add anything on the stock system will be your responsability to make it right, and don’t blame the ammeter anymore.

Run an ignition system ( or ANYTHING) straight to the batt is one of the wrong procedures for example. And then don’t blame the ammeter!

( actually ignition systems doesn’t add excessive loads even sourcing them from battery )

Well aware and it’s obvious that I accept full responsibility for all aspects of my ride. As you can see, I’m well past worrying about ammeters as mine is gone! However, these cars get modified and also driven by people that don’t know anything about electrical let alone where to even find the ammeter on the dashboard so if that alternator fails, it might get driven until the battery is dead before it gets looked at... the potential is there and if you plan on modifying these cars extensively, the first thing to do is get rid of the stock wiring arrangement.

 

[Hemirunner]

If you have an alt or batt failure and you still keep running the car no matter if the ammeter read or not the full load, you have the responsibility on don’t keep running the car under a major failure and don’t blame the ammeter.

And in any case if you still decide to run under a major failure, the ammeter will let you know what you can or not make to keep the system safe.

if your engine overheats, won’t be the temp gauge or sender blame. Except if they get a wrong reading for some damage on gauge, wire or sender.

if you decide to add anything on the stock system will be your responsability to make it right, and don’t blame the ammeter anymore.

Run an ignition system ( or ANYTHING) straight to the batt is one of the wrong procedures for example. And then don’t blame the ammeter!

( actually ignition systems doesn’t add excessive loads even sourcing them from battery anyway )

Every MSD system instructions, as well as every EFI system instruct you to run primary power and ground direct to the battery.

 

[Nacho-RT74]

Yes I know MSD instructions says to hook it up to batt. But still ignition system doesn’t sucks a lot of load even sourcing from batt.