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Generator blown?

Started by Christian Millman, June 25, 2011, 10:24:15 AM

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Christian Millman

Hi all. I tried to start up my 66 Eldo last night and after the engine attempted to turn over a few times, smoke started billowing out from under the hood. When I popped it open, the negative lead attached to the AC compressor was burnt clean through and the positive lead going to the back of the generator was badly scorched. All other wiring seems fine. Could this be a simple matter of a bad generator or should I be checking for something else too? Many thanks.

Christian Millman CLC 23152
Christian Millman 1966 Eldorado

Dave Shepherd

I'd be checking for bad engine or chassis grounds first.

TJ Hopland

I would be looking over all the electrical stuff before I connected a battery again.  Sounds like you had something important fail.   The failed ground does make some sense especially if the ground from the battery goes to the body.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

"Cadillac Kid" Greg Surfas 15364

Christian,
The positive lead from the alternator to the battery goes through a connection and they don't seem to last "for ever". I would check to see that the wire itself (should be 10 gauge and connected to the alternator with the stud connection) has not failed at these connections. If you have let the smoke out you may have poroblems.  Electrical devices are filled with smoke at the factory, and usually letting the smoke out is when they fail.
Greg Surfas
Greg
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

dplotkin

I think Dave is spot on. The starter grounds through the block & depends upon a heavy copper strap or braded wire between the engine block or accessories to the body and/orbattery negative. If that becomes loose, corroded or missing altogether, the starter will attempt to ground itself through the next available means in order of circuit resistance, which in this case is your compressor ground. That would explain the meltdown during your attempt to crank that 429. You need to take a close look at your battery cable connections, paying particular attention to the engine to body grounds.

This afternoon I was sitting in a 66 Coupe Deville with 5,000 original miles that was part of a chain of beautiful low-mileage Caddys being auctioned at the Raleigh Classic. It sold for $30,000. Beautiful car you must have.

You are going to have to perform at least some harness replacement. I wouldn't try to repair it.

Good Luck

Dan
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

The Tassie Devil(le)

Quote from: "Cadillac Kid"  Greg Surfas 15364 on June 25, 2011, 04:01:39 PM
......Electrical devices are filled with smoke at the factory, and usually letting the smoke out is when they fail.......Greg Surfas     
I thought that was only with Lucas Electrics. ;)

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Christian Millman

Thanks gents for all the help. I'm sure hoping I haven't burnt out any of the harness. I'll start checking in order of easiest to hardest and get a flatbed to a mechanic if it gets to the harder end of things.

Yes, Dan, she is a real beauty. When I bought it, I was actually looking for a 66 convertible Deville but when I saw this Eldo, I never looked back.

Best,
Christian
Christian Millman 1966 Eldorado

robert G. smits

Dan, what did you buy this time?  I was with you at Raleigh a couple of years ago and  I think you purchased a Pontiac.
Bob Smits
R. Smits, #2426
23 Cad 7P Touring
32 Cad 5P Coupe
38 Cad 90 Series
41 Cad 63 Series
58 Cad Eldo Barritz
The average man can take care of one Woman and two Cadillacs, Al Edmond AACA Past President

dplotkin

Tried to buy a 64 Coupe Deville & a 70 convertable, both under 10,000 miles. Kind of regret it but I've got 7 cars & care & feeding is no longer a walk in the park. Good to hear from you!
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

bcroe

Generators have a relay in the regulator box, that closes when the gen starts to put out enough voltage to charge the battery.  If this were ever to close without the engine running, or stick closed, big time current would flow backwards through the relay & gen.  Make sure you don't have this short before hooking it all back together.  Bruce Roe

dplotkin

Bruce: cars with alternators (Late production 62 A/C cars & all of them thereafter) have a 2 element regulator containing a current regulator and a voltage regulator. Generators use a third element called the cutout or circuit breaker, to which you refer. Generators need the cutout to disconnect themselves from the battery when the generator output falls below battery voltage. Alternators don't need a cutout as they have diode rectifiers in them to create DC current and these act as one-way valves. Current cannot flow into an alternator as it can a generator.

Dan
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker