Problem with AMP Gauge Going WILD!

[ersatz]

I have a 1946 Ford 1/2 Ton Pick Up with flathead V8. I have one of E.J. Whitney & Co. (Fullerton, CA.) 40 AMP alternator conversions. The alternator is only 2-1/2 years old and everything worked just fine.

Everything was fine until 3 or 4 months ago. Then slowly a problem with my AMP guage bouncing wildly back & forth when driving began to occur and get progressively worse. Now it happens all the time. Took it to a starter repair shop today and had it tested. They checked the battery & everything with meters and nothing showed it face. I was told it could be the Amp gauge, or a bad ground.

I've got the positive ground cable for the battery grounded to the firewall. Also a ground from the firewall to the block. What other grounds do I need?????

Your HELP appreciated!

[alan]

check the wire going thru the amp gauge loop for fraying-vibrations can cause the wire insulation to rub and ground out on the loop

[Kerk]

I would look at the voltage regulator as the possible problem.kc

[fomocoloco]

i've had the same problem for several months. charges good, bounces all over.

[rotorwrench]

You may have a loose power wire somewhere. If it has an internal regulator and diode bridge there could be a problem internal to the alternator assembly. Diodes can come loose from the bridge piece and cause the current to fluctuate. THe diode bridge is what changes the alternating current to DC current for DC regulation. Alternating current makes an old inductive meter go nuts.

[deuce lover]

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Why don't you call Tom Whitney (Ed Whitney's son) who actually makes those units and ask him? I have had 4 done by him(12V - ground) with no problem.Installed in 34 & 35-36 Fords.

[ersatz]

Okay........ Thanks for all the input fellas!

I've checked the wiring as alan mentioned everything seems fine there.
Forgot to mention that the Voltage Regulator is new.
Tried calling Tom Whitney as deuce lover suggested. No answer, will try again.

I was talking with a knowledgeable mechanic who a friend uses and he mentioned that sometimes on alternator conversions the armature becomes warped. Sounds reasonable since the ammeter needle goes crazy when RPM's are increased. I'm going to remove the alternator and reinstall the generator and see if it makes any difference. I'll let you know...........Thanks again everyone!

[ersatz]

Finally got a hold of Tom Whitney by phone. He suggested the regulators inside may be bad. So, while the generator is on, I'll have the alternator checked out.

[wga]

These alternators are internally regulated - as rotor mentioned. You by pass the regulator, or if you want to use it for an original look fake out, toss the internals. My stock amp gauge has worked perfect for years.

[ersatz]

Yep, you guys are right about not needing the actual voltage regulator. It's just for looks. Changed out the alternator for the original generator and all works perfectly. Haven't seen the Ammeter work correctly for sometime. Tom Whitney is sending me a replacement internal regulator to replace the defective one. Thanks for the input!