1952 Pontiac Chieftain Generator Blew

[MercMontMars]

Hi there, I finally got my 52 Chieftain running, and I took it for a short cruise and after letting it idle for a bit in the driveway I heard an awful grinding noise along with shavings flinging up with the radiator fan. I shut the car off and checked everything, noticing that the generator fan pulley had split in two. I have since removed it and am searching for a new pulley or something sufficient just for now as I do not want to buy a whole new unit yet. What might have caused this? I’m not sure if it was the belt being too tight or if it was just old and ready to go. I don’t want it to happen again so I’m asking here to see if it’s happened to anyone else before.

Thank you for any help!

[Rusty_OToole]

Never saw that before. Looks like a case of metal fatigue. Could be there was a flaw in the metal and a crack developed over the years until it finally got long enough to break the pulley apart.

If there is an auto electric shop in your town they may have a pulley to fit. Most of them have a box of old pulleys under the work bench.

While you have it apart may be a good time to have the generator rebuilt.

Edited May 29, 2023 by Rusty_OToole (see edit history)

[MercMontMars]

@Rusty_OToole Thanks for the reply! I thought so too, looks like a crack, definitely not something that started yesterday. Glad it happened when it did. That’s a good idea, I never thought to call some local auto electric workers, I’ll call around and see if anybody has some pulley fans. How extensive is the work to rebuild a generator? Haven’t done one yet, doesn’t seem to be much to it but I plan on doing a 12v conversion soon only because this car will be my daily. I love originality but not for things like this.

[Bloo]

I've never seen that failure.

 

Generators are pretty simple. An "auto electric" (starter/alternator/generator) shop can probably come up with a pulley and fan to fit that, though it may not be an exact match. I'd check with CPR and see if they have one laying around.

 

There's a bearing in front. If there's no oil cup, its the same bearing as the alternator (and even if there is an oil cup, the one for the alternator will still fit). In the back there is probably a bushing. Inspect it for wear but it is probably fine. An auto electric shop can get you the bushing if you need it. It is most likely a standard one that fits about 50 years of Delco generators.

 

The brushes wear out. Look at pictures of the new ones for your generator to estimate how much wear you have. When new, the brushes have to wear a curve in the face right away in order to break in, so allow for this when estimating wear. They probably look more worn than they are. Beyond that, the commutator might need machining, and if so that is a job for the auto electric shop., but often you don't need to. The insulation between the segments of copper should be below the surface. If it isn't, make a tool and scrape a little out. On some generators a broken hacksaw blade will work, but on most you will have to find something a little thinner than a hacksaw blade in order to fit between the copper segments. You might need to scuff up the copper a little if it is black. Don't use anything that will leave grit behind.

 

If it works, I would probably just inspect the brushes and see if there's some useful life left in them. If there is, I'd leave it alone.

 

[Fordy]

If its 6 volt the field coils should measure in around 3 ohms and for 12 volt at 6 ohms. Make sure they are nice and clean as oil and muck can deteriorate the insulation. While you are poking about with an ohm meter check that all the commutator segments are not shorted to the steel parts - just 1 short there will give grief.  Other than that - just as Bloo says although some generators have a bearing both ends. Todays bearings are also normally sealed, so the oilers become redundant.

[Pont 46]

If you are thinking about going to 12 volt, and not keeping orginial, and a daily driver, what about a alternator?, 

[Rusty_OToole]

If it was mine I would check the bearings, commutator and brushes for wear and if it was worn let the shop rebuild it while it is out. If it is in good shape just replace the pulley. You need an air ratchet or good electric ratchet to rattle off the nut so if you don't have those let the shop replace it.

[Marty Roth]

Leave it 6 Volt

 

Just because you plan to use it as a daily driver does not necessitate 12 Volts,

and you'll have several issues making other items functional. changing all bulbs including instruments, heater, radio, some sending units, gas gauge, turn signal flasher, etc., etc., etc.

6 V worked just fine until the industry started adding a huge number of electric accessories, and scrimping by going to smaller gauge (cheaper) wiring.

 

You can always use a USB rechargeable remote bluetooth speaker and free app for Sirius radio on your i-phone to get any kind of sounds if you don't care for AM.

(My 1915 Hudson and 1937 Buick roll down the road listening to Linda Ronstadt, Doc Severinsen, Beatles, Beach Boys (no Rap), Show Tunes ...)

[Robert G. Smits]

I had a similar alternator pulley failure on my 86 Mercedes during the 2021 Buzzy tour.  Fortunately the catch trailer operator was employed by UPS servicing their Mercedes vans and was able to find a identical used pulley at a automotive electrical repair shop.  Sometimes you get lucky The Mercedes dealer wasn't interested in helping and  Pelican parts estimated 5-7 days.

[Rusty Heaps]

That should be a fairly easy pulley to find, GM wide belt. I have had the local shop convert generators from 6 V to 12 V for a reasonable price. 

[Ben Bruce aka First Born]

19 hours ago, Marty Roth said:

Leave it 6 Volt

 

Just because you plan to use it as a daily driver does not necessitate 12 Volts,

and you'll have several issues making other items functional. changing all bulbs including instruments, heater, radio, some sending units, gas gauge, turn signal flasher, etc., etc., etc.

6 V worked just fine until the industry started adding a huge number of electric accessories, and scrimping by going to smaller gauge (cheaper) wiring.

 

You can always use a USB rechargeable remote bluetooth speaker and free app for Sirius radio on your i-phone to get any kind of sounds if you don't care for AM.

(My 1915 Hudson and 1937 Buick roll down the road listening to Linda Ronstadt, Doc Severinsen, Beatles, Beach Boys (no Rap), Show Tunes ...)

 Does not necessitate,  but does not hurt.   IT CAN ALWAYS BE CHANGED BACK, in the unlikely event any one cares to. I did mine 10+ years ago.  Still waiting on all the problem scenarios folks are always talking about.😂

 

  Ben