Ammeter burning up?

Hi guys, After returning from Monterey last week I noticed that my ammeter has hazed up internally behind the glass as if from smoke, and no matter how charged the battery is I continue to get over 50 amps of charge (needle pegged) when I'm running down the road. If I shut off all the ancillaries (cooling fans, AC, etc.) it's still charging 50 amps. I've checked out my alternator and battery and at least on the bench they're all fine, voltage regulator in alt. is fine, battery shows full charge and passes a load test. Despite this, in the car it constantly charges like the alternator has been full fielded. This has led one of the terminals on the back of the gauge to melt down, certainly not normal operation. Has anybody else experience this issue, and if so, what was the solution? Thanks!
 

Rick Muck- Mark IV

GT40s Sponsor
Supporter
There is a wiring modification to correct the "50 amp all the time charge" issue. My chassis (2171) has the same issue although my amp gauge is still OK. I have not done the repair yet but it is on the short list of upgrades to do soon.

I can provide the tech bulletin with the instructions if you need it.
 
Hi Rick,
Same problem with P2127, please send or publish the fix...also, still waiting for list or catalog of upgrade kits available from your co. Ie:air leak seal kit, rear window...etc.etc.
Thanks Rick!

Dick Carr P2127
[email protected]
 
Thanks Rick! ...Is there a list of other S.B.'s or other factory upgrades available for the earlier SPF Cars?
Thanks for all your help!
Dick Carr
P2127
 
Last paragraph in Ricks attachment#5 post says it all, when I read the thread I thought why the heck are they using an amp gauge instead of battery condition, originality has its price!
 
Not sure who told me, but I was told that Ammeters are a big cause of car fires.

For that reason, in my P4 I am replacing the Ammeter, with a more helpful and not fire-prone volt meter.
 
I replaced the ampmeter with a voltmeter. You can find black face Smith gauges on some Cobra supply sites. I got mine from the GaugeGuys.com. If you want to put a amp meter back in I have one I'll let go cheap. If you put in a voltmeter you'll have to put the two wires that go to the amp gauge together. Those wires are always hot so you shouldn't use it as a source for the volt meter (your battery will go dead). You'll have to find a voltage source off the ignitions switch.

IMHO the voltmeter is the way to go. See pictures.

I posted most if not all of the SPF service notes for early cars (see link). Some superseded others but I post all of them for historical reasons so be careful as there may be newer ones.

http://www.gt40s.com/forum/superformance-gt40s/30298-superformance-service-notes-other-info.html
 

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Jim Craik

Lifetime Supporter
Hi Kevin and Dick,

That's kind of scarry.

Steve Woods replaced mine a few years back, so I think I'm OK, but for the others, does anyone know the chassis numbers or the gauge type that is effected?
 
Thanks Richard for the Tech bulletin & upgrade summary. great help!
Glad Kevin caught the problem before it got worse. Hope you got my Monterey pictures Jim!
Dick Carr
 
Thanks Rick! I'm going to make this change right now. That being said, I have to agree with the rest of the volt meter crowd, more useful and less of a fire hazard. I'm definitely going to swap over to volts ASAP, especially considering how hot it appears the ammeter got. At least for the moment I can run it without feeling like it's going to burst into flame, the Webers already have that threat very well covered. :laugh:
 

Jack Houpe

GT40s Supporter
If you look at the wiring in the early SPF cars you wonder what where they thinking or drinking when they designed the wiring. If you follow the power wires they go from the back to the front then back to the main fuses located in the engine compartment then back to the front of the car creating about 14 feet of wire and resistance in that wire. I located my battery in the passenger foot well then put the main fuses up front then did away with the back and forth wires. Also not many people use amp meters, a true indication of battery condition is the measurement of potential power (voltage) not kinetic power (current).
 

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Steve Wood (PANAVIA)

Lifetime Supporter
Jims is fixed,one of the first things I did to that car -including upping the gauge of the Alternator to Battery Wire and inserting a mega fuse so if the alternator shunts, the car doesnt have any damage.

, -- the key thing here is Alternator Size - if you are running an Alternator from the 1960s that is a 50-60amp or so affair - then you are OK with the AMP meter, but do note ; you will never keep up with your FANS and AC at idle.

Keep in mind that Alternators dont put out the full amperage they are capable of at idle, if they are rated for say 100AMPS , you might be getting 40-50 at idle.

most of the cars we see have a hot-rod style alternator , like Powermaster - and they have been getting overtly large and powerful. We have seen them break the 150A barrier recently, and in this realm of GT40 we see 100-140Amp all the time.

there is NO REASON to have ( Keep ) an AMP gauge in your 40' - it is clinically unsafe with any alternator above 55-65 AMPs. (IMHO)

AKA: Dont play Apollo 13 with your 40'- put in a Volt Gauge.

(Again - in my humble opinion as a Captured German Scientist)
Steve Wood
 

Jack Houpe

GT40s Supporter
Jims is fixed,one of the first things I did to that car -including upping the gauge of the Alternator to Battery Wire and inserting a mega fuse so if the alternator shunts, the car doesnt have any damage.

, -- the key thing here is Alternator Size - if you are running an Alternator from the 1960s that is a 50-60amp or so affair - then you are OK with the AMP meter, but do note ; you will never keep up with your FANS and AC at idle.

Keep in mind that Alternators dont put out the full amperage they are capable of at idle, if they are rated for say 100AMPS , you might be getting 40-50 at idle.

most of the cars we see have a hot-rod style alternator , like Powermaster - and they have been getting overtly large and powerful. We have seen them break the 150A barrier recently, and in this realm of GT40 we see 100-140Amp all the time.

there is NO REASON to have ( Keep ) an AMP gauge in your 40' - it is clinically unsafe with any alternator above 55-65 AMPs. (IMHO)

AKA: Dont play Apollo 13 with your 40'- put in a Volt Gauge.

(Again - in my humble opinion as a Captured German Scientist)
Steve Wood

Couldn't agree more, I have a 200 amp alternator, with the electric water pump, fans, heater pump, msd dis, efi computer its necessary.
 

Steve Wood (PANAVIA)

Lifetime Supporter
They copied the ford /JW harness from 1966- again if you have a 55amp alt as in a 1965 alternator , then no need to worry - if you have moved forward in advancements in other technology - then you might want to consider a change ---
 
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