LVMott

I am planning to change the generator in a 1959 Corvette to an alternator. The car has an Ammeter in it. I have been told that I will have to change the Ammeter out to a Voltmeter. This is the first time I have heard of this. Could someone clarify this for me.

jim lockwood

Well, what you were told isn't true. You can keep using the Ammeter without any issue.

JF in MI

Nonsense. I changed on my '60 and the instruments are fine like they were before.

LVMott

Thanks Guys. I appreciate the prompt replies. It really clears things up.

1Hotrodz

No need to change to a voltmeter. But ammeters are not as safe as voltmeters. Reason being is: the total electrical current passes thru the ammeter which is located inside the cabin, which can cause a risk of fire, if overloaded. I'm assuming the new Alt puts out more current than the old Gen. If that's the case then you could run the risk of overloading the ammeter and its wiring. So it's probably a good idea to switch to a voltmeter just to be safe. But if outputs of new Alt and old Gen are equal then no need to switch to a VM.

jforb

You might look into why people say that. It's pretty common for guys modifying old cars to add lots of new electrical stuff, such as power windows, electric fans, air conditioning, etc that take more power, and then use an alternator that provides a lot more current than the original generator did. This can result in quite a bit more current in the car's electrical system, and with the wires and ammeter sized to handle a 30-40 amp total load now being subject to 60-80 amps, the wiring and ammeter could be overloaded.

So...if you're just replacing the generator with an alternator, and you don't change anything else, you should be fine. But if you're also changing other stuff that requires a high output alternator, you might want to look into replacing some wiring, and thinking about how the ammeter is loaded under the new system.

fwiw, I replaced the generator in my 62 with an alternator, and it's working just fine with original sized wiring and ammeter.

silver837

Does your generator have the tac drive ?

JF in MI

The above (higher output and/or use) is true and if you go that route better wiring could be necessitated. One scenario is a 40 amp alternator (like I installed) and the ammeter only going to 30 amps. This only counts if all the power is being routed through that 30 amp wiring/ meter. In my case I have electric power steering which required 8 gauge wire (IIRC) because it draws a pant load of amps so it is fused directly from the battery. I also have halogen headlights which work off a direct battery fused relay. None of these register on the ammeter. I might note that in normal (even heavy) charging operation I've never seen an amp increase over 15.

LVMott

Yes it does. I am looking at Authentic Automotive Vintage Alternators because it has the fittings to put the old tach drive on the alternator.

Dmil7

Guys, what type of mount are you using for the alternator? I want to install one on my 59 but it seems most are low mount and the engine mounting bracket interferes. Are yours mounted high, valve cover height or higher?

Thanks for the information. Good thread.

jforb

I used the 1963 mount on the 1962 manifold, and a double pulley on the alternator so it would use the forward belt position on the lower pulley, and the shallow water pump pulley. But this is with it on the pass side. if you put it on the driver side, you should be able to use a more common lower alternator bracket and keep the belt back all the way.

John S 1961

You can add a 6 inch 14 gauge "shunt" across the terminals it will carry a lot of the load and the ammeter will still work. Study up at madelectrical.com. a couple wires and terminals and things will work well.

vette-jag

I installed a alternator with 90A and Tach drive in my 1957 6 years ago. I have electric power steering, electric fan and EFI with MSD, therefore a strong 10 AWG cable directly from the alternator to the battery. I have replaced the ammeter with a voltmeter. Works perfectly.

csherman

Vette Jag beat me too it
I have a shop that will install a Bosch alternator in a generator case
Look 100 percent original
1 wire hook up
I put a date coded one on a 56 !!!
Looked great !!!!!

Dmil7

That helps. Thanks for the picture.

LVMott

Did you have to change the wiring to handle the increased amp load?

vette-jag

As already written, just an additional cable directly from the alternator to the battery.