Re: [Amc-list] a study in failure

[Wrambler242@xxxxxxxxxxx]

Wow, that's amazing to walk in and get one off the shelf!
I had no idea they were that miserable at charging!
I'b stuffing a nice high capacity battery in that thing.
don't be adding A/C and a stereo either.

--
Mark Price
Morgantown, WV
1969 AMC Rambler, 4.0L, EFI, T-5
" I was different before people dared to be different" 

 -------------- Original message ----------------------
From: Tom Jennings <tomj@xxxxxxx>
> The generator died on Wednesday. It died because I chaned the radiator and 
> fan. It really is a case study in failure modes and how they happen.
> 
> Driving back from Irvine Wed night, about 5 mi from home I started getting 
> fan belt slippage when I revved more than 2400, and headlight and dash 
> brightness changes that always means charging problems. Nothing serious, 
> though it did alarm me a bit. Made it home just fine. Popped the hood, 
> poked the fan belt and it was much looser than I'd left it a week ago. At 
> idle, there's a fan-belt-y scritching sound, like a wet or loose belt... 
> when I revved it from under the hood, the headlights visibly went 
> bright/dark/bright/dark, the variable output of a flakey charging system.
> 
> Next morning I start the car to examine, noise is still there. Moving 
> around the car (so ear directionality works) I decided it was the 
> generator; when I put my hand on it I could feel it vibrating. Bad bearings 
> would be no surprise.
> 
> I pull the generator, and here's the cascade of related failures:
> 
> Both armature (A) and field (F) wires are very loose. The gennie has been 
> charging just fine anyways, but the connections were loose and greasy, 
> waiting to fail. The ground wire is tight, but missing one ear of the spade 
> lug.
> 
> Pull out the mount bolts, the front lower mount/pivot falls out. An old 
> fracture, it's all rusty. This is most of the noise source; the front of 
> the gen dropped, loosened the belt, and was jumping up and down as it spun.
> 
> Spun by hand, the front bearing is noisy, the rear bushing quiet, but the 
> oil cup long since busted off so it's gone un-lubed for who knows how long.
> 
> The brushes wore a deep, deep groove in the commutators, the damned thing's 
> probably original. It charged just fine though! A testament to generator 
> reliability.
> 
> So putting on the new fan belt and tightening it popped the broken bolt out 
> of place -- after 200 miles of driving -- causing belt slippage and 
> vibration, which wiggled the loose wires and made the charging system 
> intermittent.
> 
> Chuy's Electric in East LA had one in stock! $60, lucky me. Repaired the 
> ground wire, broken bolt, etc it all went in OK.
> 
> Man, generators suck for making juice. Does basically nothing at idle, 
> charges somewhat OK at 1800 rpm. They weigh 3X an alternator, but 
> alternators are not Cool.
> 
> 
> 
> (I worked with this guy, Owen, who bought only old Cadillacs (late 1970's), 
> did zero maintenance and drove them til they died. "I don't open the hood, 
> it only costs me money". There's something to this, you change a fan belt, 
> who knows what else will break! :-)
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