63 alternator concern

[Michael G.]

My blue 63 is just about to leave for judging at Joplin. I started it up and the battery gage went about a quarter of the way into discharge. The alternator top is very hot, none of the wires seem to be heating up. Have I got a bad alternator or could it be something else?

Thanks,

[Michael G.]

Re: 63 alternator concern

Update: Not good. I changed the alternator and voltage regulator to ones that I know are good (from my other 63). System still discharges when running, but still shows no discharge when not running, with key in "ON" position.

Help!!!

[Tom H.]

Re: 63 alternator concern

Not sure where to point you. Are your battery cables tight ???

[Michael G.]

Re: 63 alternator concern

Hi Tom, The battery cables are new and tight. All other wiring is new.

I'm wondering if I might have a short in the new wiring. I'm no electrical engineer, but I'd guess that it'd have to be on a circuit that is live only when the engine is running.

[Joel T.]

Re: 63 alternator concern

Mike;

Is the wiring new? Your last post seems to imply that it might be. If that is the case, I would go over the entire installation to be sure you have nothing crossed or miss-connected. Check your connections through the firewall as well.. I had that issue with my 1965... not charging. How about your grounds? Are they clean and tight? If you rev the engine, do you at least get a neutral reading?

Joel

[Joe R.]

Re: 63 alternator concern

Michael, change the battery from you other car and see if that helps. Is it possible you have a huge drain on the battery like your headlights being on and rolled over so you cannot see the light from them.

Sounds like a big drain or a battery going bad.

JR

[Michael G.]

Re: 63 alternator concern

Hi Joel, The wiring is new. The battery is a new lead-acid tar top. When I rev the engine, the discharge shown on the battery gage increases. I have a spare battery gage, I can switch it to see if that is the problem. Does a battery gage perform opposite if you reverse the polarity?

Joe, the headlights are turned to the open position, they are not on. I would guess that any huge drain on the battery would also show up on the battery gage with the key on and the engine off. With the key ON, the gage is in the neutral position. I'll check all of the grounds first.

[Bob R.]

Re: 63 alternator concern

I think you may want to check the wiring on the battery gauge against a wiring diagram. I think that might be the problem.

[Edward J.]

Re: 63 alternator concern

Mike, I can give you a few items to look at, First is the belt have the proper tension? a loose belt will cause a discharge, next look at the connections a alt.and regulator, do a wiggle test, this may require someone to watch the gage while you wiggle the wires, To see if you get a change on the amp. gage, Next would be to make sure that there is battery power at the alt. and regulator red wires.

There is a test to do with belt to see if its lose or glazed badly, take your thumb and apply pressure to alternator fan with a downward or upward motion, If the pulley slips around the belt you need to tighten or replace.

[John H.]

Re: 63 alternator concern

I think you may want to check the wiring on the battery gauge against a wiring diagram. I think that might be the problem.

Mike -

The 18-ga. black wire from the battery gauge goes to the battery cable stud on the starter solenoid, and the other 18-ga. red wire goes to the screw terminal buss on the horn relay. Both wires in the gauge connector should show battery voltage with the engine off.

With a voltmeter across the battery terminals, it should show 12.4-12.6 volts with a fully-charged battery and the engine off; with the engine running at 1500 rpm, it should show 13.5-14.2 volts across the battery terminals if the system is charging. If the wires are reversed in the gauge connector, it will read reversed; the gauge is simply a sensitive voltmeter reading the difference in voltage between the horn relay buss and the stud on the starter solenoid, displaying whether current is flowing from or to the battery.

[Michael H.]

Re: 63 alternator concern

I think you may want to check the wiring on the battery gauge against a wiring diagram. I think that might be the problem.

I think you're right. Either the wires are reversed in the connector, or the terminals are installed incorrectly on the back of the guage. (yes, that can be done)
You can test for this condition by turning on the headlights with the engine off. If the guage shows a charge instead of discharge, it's wired back asswards.

[Norris W.]

Re: 63 alternator concern

One thing that we saw in the shop about 25 years ago, and I can't remember what it caused, but there's a black wire with a BIG eye on the end that grounds to a starter bolt. A car came in with electrical problems and this wire had been put under the center stud on the starter solenoid. I can't remember if it had cooked something or if the elect. system was crazy, but another local shop that did a bunch of Corvette work told me at the time that he'd seen it several times over the years. Hate to mention it since I can't remember details, but obviously it's an easy thing to check visually.

[Michael G.]

Re: 63 alternator concern

Thanks guys,

John, great explanation...even I understand it now

The car is now at my office and I am at home, so in the morning I'll perform Michael's test to see if the wires are reversed. Please stay tuned...

[Timothy B.]

Re: 63 alternator concern

Michael,

Take a quick look at the pink wire that runs under the top ignition shield and make sure it's clear of the metal.

[Michael G.]

Re: 63 alternator concern

Well...I performed Michael's test (turning the headlights on with the engine off). I found that, apparently, those particular headlights generate electricity, because the result was a large positive reading on the battery gage. I'm sure the Department of Energy will want the hear about this discovery.

First problem solved, now I just need to find out what is reversed in the battery gage wiring, then put all the various components back on their appropriate vehicles....

Thanks for your help everybody...