61 Generator Woes

[Ed Jennings]

For the past few weeks, my 61 has quit charging after being driven for a few miles. I took the generator and regulator to an automotive electric shop and after much discussion had the generator rebuilt on speculation, even though it checked "good".Same problem except the generator seems to charge a bit more when the engine is first started. The regulator also checked "good", and appears brand new inside, though it was apparently replaced some years ago. The battery, BTW is a new "Diehard", and definately takes a charge when the system is working.

I've been throught he wiring diagram and don't immediately see any areas that I would consider to be heat sensitive. Apparently the current feeds from the regulator, through the ammeter, and back to the starter solenoid at the same terminal that the battery feeds into. The solenoid is subject to a lot of heat. Could that be a problem???

If one of you electrical experts could provide any assistance, it would be greatly appreciated.

[Ed Jennings]

Re: 61 Generator Woes/plot thickens

I decided to check the connections at the ammeter, since I had recently refurbished the dash, and sure enough the connections were both loose. After tightening them, I reconnected the battery and turned the key. Smoke, LOTS of it poured out from under the dash. I quickly, but not quickly enough, turned the key off, and disconnected the battery. What was overheating was the power wires for the gas and temp gauges. They come directly off the ignition switch. (unfused) I fail to see any connection, other than that I may have somehow grounded something while rooting around under the dash. (those who have been there will appreciate the notion of trying to hold a flashlight in your mouth while standing on your head looking for small objects through bifocals.) I guess I'm gonna have to take the wiring harness apart and replace some of the wiring. Not one of my favorite operations. Anyone see any connection between the charging problem and the fire? I don't see one, but I thought I knew a fair amount about automobile electrical systems until this week. Now I'm convinced I know very little. HELP!

[Ed Jennings]

Re: 61 Generator Woes/plot thickens

I decided to check the connections at the ammeter, since I had recently refurbished the dash, and sure enough the connections were both loose. After tightening them, I reconnected the battery and turned the key. Smoke, LOTS of it poured out from under the dash. I quickly, but not quickly enough, turned the key off, and disconnected the battery. What was overheating was the power wires for the gas and temp gauges. They come directly off the ignition switch. (unfused) I fail to see any connection, other than that I may have somehow grounded something while rooting around under the dash. (those who have been there will appreciate the notion of trying to hold a flashlight in your mouth while standing on your head looking for small objects through bifocals.) I guess I'm gonna have to take the wiring harness apart and replace some of the wiring. Not one of my favorite operations. Anyone see any connection between the charging problem and the fire? I don't see one, but I thought I knew a fair amount about automobile electrical systems until this week. Now I'm convinced I know very little. HELP!

[Mike Jones]

Re: 61 Generator Woes

Ed:

Since you've gotten no other responses, I thought I'd put in a personal experience.

I had a similar problem where my generator was not charging and likewise I took it to a generator specialist who, while it checked out OK, suggested that it needed a rebuild anyway (brushes worn). After putting it back on the car, again no charging. To make a long story short, it turned out to be a lack of a ground on the voltage regulator. Corvettes (for obvious reasons) are notorious for grounding problems. Perhaps you have a ground problem that is somehow heat sensitive.

Mike

[Mike Jones]

Re: 61 Generator Woes

Ed:

Since you've gotten no other responses, I thought I'd put in a personal experience.

I had a similar problem where my generator was not charging and likewise I took it to a generator specialist who, while it checked out OK, suggested that it needed a rebuild anyway (brushes worn). After putting it back on the car, again no charging. To make a long story short, it turned out to be a lack of a ground on the voltage regulator. Corvettes (for obvious reasons) are notorious for grounding problems. Perhaps you have a ground problem that is somehow heat sensitive.

Mike

[Jack H.]

You won't like this....

As the subject title states, my suggestion is for you to STOP doing exploratory work and seek a skilled/competent local auto electric shop and have them debug and repair. When you SMOKE the wiring harness of a classic old car, tells me you're in over your head and it's not worth the risk of further experimentation.

Ammeter is NOT in series with charging system/battery. If it were, you'd have #00 gauge wires running under the dash as ammeter would have to absorb 100% of max system current flow (gets REAL beefy when you're cranking the engine)! Ammeter is connected in a parallel/shunt arrangement where 'controlled' resistance wiring is used to pre-define the impedance characteristics of the shunt circuit and that includes the winding impedance of the ammeter guage.

Generator is notorious for not charging battery IF/WHEN car is not driven routinely at cruising speeds. Takes more then typical idle RPM conditions for gen/reg to 'open up' and begin to deliver a healthy charge to battery. If car is driven infrequently, you can be 'fighting' the natural flow of things....

Way to really tell if you've got a charging system malfunction is to place a voltmeter across the battery and either drive 'er or crank 'er up well above idle. Should see voltmeter climb above native battery level (12-13.5 VDC) as charging system compensates and pushes into solid charging range (14-16 VDC depending on state of current residual charge on battery as well as setting of VReg).

This method gets around 'funnies' caused by defective ammeter, ammeter wiring, 'mods' made to old/original wiring harness assy. The 'smoke' that poured out of your dash tells me you either had a marginal system short to ground that you somehow made worse or you've sure got one now! Bad things can happen (explode battery, grenade instruments, melt down wiring harness, burn/explode the whole car) if you pursue further without SOLID system knowledge....

[Jack H.]

You won't like this....

As the subject title states, my suggestion is for you to STOP doing exploratory work and seek a skilled/competent local auto electric shop and have them debug and repair. When you SMOKE the wiring harness of a classic old car, tells me you're in over your head and it's not worth the risk of further experimentation.

Ammeter is NOT in series with charging system/battery. If it were, you'd have #00 gauge wires running under the dash as ammeter would have to absorb 100% of max system current flow (gets REAL beefy when you're cranking the engine)! Ammeter is connected in a parallel/shunt arrangement where 'controlled' resistance wiring is used to pre-define the impedance characteristics of the shunt circuit and that includes the winding impedance of the ammeter guage.

Generator is notorious for not charging battery IF/WHEN car is not driven routinely at cruising speeds. Takes more then typical idle RPM conditions for gen/reg to 'open up' and begin to deliver a healthy charge to battery. If car is driven infrequently, you can be 'fighting' the natural flow of things....

Way to really tell if you've got a charging system malfunction is to place a voltmeter across the battery and either drive 'er or crank 'er up well above idle. Should see voltmeter climb above native battery level (12-13.5 VDC) as charging system compensates and pushes into solid charging range (14-16 VDC depending on state of current residual charge on battery as well as setting of VReg).

This method gets around 'funnies' caused by defective ammeter, ammeter wiring, 'mods' made to old/original wiring harness assy. The 'smoke' that poured out of your dash tells me you either had a marginal system short to ground that you somehow made worse or you've sure got one now! Bad things can happen (explode battery, grenade instruments, melt down wiring harness, burn/explode the whole car) if you pursue further without SOLID system knowledge....

[Ed Jennings]

Re: You won't like this....

I opened up the wiring harness and found that the power supply to the fuel gauge was the only apparent casualty. I repaired that wire, checked for any grounds, and finding none, I tried it again. Everything works as advertised. I haven't had it on the road again yet, but I am suspicious that a few miles of driving may lead to another no charge situation. If that is the case, then a trip to the auto electric shop is definately indicated.

[Ed Jennings]

Re: You won't like this....

I opened up the wiring harness and found that the power supply to the fuel gauge was the only apparent casualty. I repaired that wire, checked for any grounds, and finding none, I tried it again. Everything works as advertised. I haven't had it on the road again yet, but I am suspicious that a few miles of driving may lead to another no charge situation. If that is the case, then a trip to the auto electric shop is definately indicated.

[GDaina]

Re: You won't like this....

If my memory serves me correct, believe the generator starts to charge above 25 MPH maybe 30.

[GDaina]

Re: You won't like this....

If my memory serves me correct, believe the generator starts to charge above 25 MPH maybe 30.

[Ed Jennings]

Re: You won't like this....

Actually, it starts to kick in just above idle speed, 1000-1200 RPM.

[Ed Jennings]

Re: You won't like this....

Actually, it starts to kick in just above idle speed, 1000-1200 RPM.