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My 235 still has the old Generator..I dont think it is keeping my Battery charged,can i switch over to an alternator? Or can I still get a generator...

Yes, you can still get a generator (6v or 12v - you do not state which you have). It is also possible to get a generator rebuilt (6v or 12v).

(Expensive) 6v alternators are available and 12v alternators are readily available.

12v alternators (and mounting bracket) are usually cheaper than generators.

The right alternator can produce more current than a standard original generator (unless you have a school bus generator).

If you want to stay stock-looking, a generator will be your choice.

I think there is a company that makes a 6v alternator packed inside a generator housing.

Tim

Awsome Tim..Thanks...So I can go either way...I have 12 volt..Thanks for your help...M/G

Mike G.

You can fix the generator or switch to a alternator...just depends on what you want. The most logical switch to a alternator would be a readily available SI unit in 12 volts. This would mean some of the electrical items on your truck would have to be changed to that voltage.

If you're on a budget, fixing the generator is OK too. It would be cheap and easy and should keep the battery charged just fine. Keep in mind that there is a brain the tells the dumb generator when to charge...it might be what's out to lunch! Before you do anything, you should test your charging system and battery and see what is actually going on. No sense wasting hard earned dough when it's not necessary.

There might be some troubleshooting instructions in the Tech-Tips section...take a look.

Stuart

Stuart, do they check them at ..auto parts stores?? I could prob. just bring it in..you think

Mike G.

You probably couldn't find a single soul in a auto parts store that has ever seen a generator. A shop specializing in auto electrical would be your best shot. The generators are pretty basic and easy to fix. If they haven't cooked the commutator or burned a field coil they can be tuned-up for dollars.

The generator probably could use new brushes and a light sanding of the commutator, but again, the problem could be somewhere else. If the truck has a ammeter, this would be the first step. Let the 'on board diagnostics' tell you if the generator is even charging. Look at the battery, it needs clean cables, water and shouldn't be over four years old.

A faulty voltage regulator or a broken wire will not allow the generator to charge properly. Even a loose fan belt will do it. Lots of stuff to look at in the search for the culprit.

Stuart

I did go thru all of the above..Except for The Volt reg,Broken Wire..I have a pretty new Battery and cables,,My ammeter!!!! that thing has not moved in a while..It is stuck as a matter of fact.What is that telling me???It should jump a bit?? Shouldnt it..

Mike G,

If your generator isn't charging then your ammeter will never move to the + or charge side, but it should show a discharge - when you turn on the lights or toot the horn. If it does none of this then it is broken. In order to determine which component is bum...generator or regulator, you will need a meter to read DC voltage. There is a simple procedure to test the generator and prove it's ability to charge. If it passes this test then the regulator and/or wiring is usually at fault.

Stuart

I went thru the Proceedure out of my Truck manual last night...Looks like I will hit this this weekend..Maybe tonight..About the Brushes..if i need to replace them are they easy to find??Where?

Stuart..what guage wire is used from the generator to the Regulator..I should just go ahead and replace that also..??You think?

remeber if you removed the generator it will need polorized or it will not charge ..

Polorized..I dont know what that means

Just did a search on Polorizing..When I put the Gen back in..Strike the Field terminal with the Armature termanal together,,as to make sprak. Correct?

yeppers Mike

Mike G,

I still am not clear on what rig you have! To polarize the generator you momentarily touch a jumper between BATT and ARM. The main wire from the ARM to voltage regulator is usually a 10 gauge wire. The book shows the field wire as only 18 gauge...that sure is small. I would use at least a 16 gauge if for no other reason than durability.

I don't know if you could find the brushes on the shelf at a parts store or not...give it a go. Good luck and edit your profile to show your truck model and year...it helps when you ask questions.

Stuart

Incase My edit did not work...235 55 3/4...I did take the Gen off a while back...Its my understanding that the previous owner had an ace Mech...old timer. I am betting he went thru everything when he rebuilt the Engn. Just do not know if he did anything to the Gen...So I will start with a charge..then Jump between Batt and arm..check ammeter..see if it will dance for me..hit the lights ect,,,Also Might as well replace the wires..I have enough of wire...thats for sure..Thanks Guys..

I unhooked my generator once when rewiring my 53. It took a long time for the battery to finally die and for me to realize something was up. I took the generator and volt reg. into a starter/generator repair shop so they could test it. Guy goes to hook it up, does a double take at the v.reg and walks over to the wire wheel and cleans the contacts. Duh! Both worked fine, just the bad connection from the rewire! Didnt ever repolarize it. Put it back in the truck and wow, look at the ammeter go! Been fine ever since.

I was going to post a very similar message as rustednuts did just above. I owned many cars with generators, and they are every bit as good as an alternator, but a generator becomes marginal if a person is running an air conditioner or other high load devices. The first thing to do, would be to disconnect the battery ground cable, remove the voltage regulator, remove the cover, and, with a diamond file carefully clean the points. This will solve tho problem in majority of situations. Even though the voltage regulator is sealed, the points will oxidize if there is enough ambient moisture. I probably still have a manual with the testing procedures if you need to go further. A lot of generators have a brush cover which can be removed to check the condition of the brushes.
Bob

I started my search of the problem yeastorday..I replaced the 2 wires..and the field wire was hanging on by a thread..Didnt notice it till I pulled back the boot on the wire and looked at the crimp. The nuts on the gen. terminals did have some rust..prob. from my power washing they were not tight either.There was also some corrosion on the reg.screws.Put a charge on it this Morning. I have a feeling this was the prob. But whats good is I am digging into the wireing..something i am not to familiar with.(with the help of my shop manual)I called My vender,cause my Ignition locked up on me,it was pretty new and only started my truck maybe 2-3 times a month,and they are sending me a new one N/C..I will try to put a needle in the hole to pry it loose..Maybe I should have used some of the dielectic greese before I put the ignition into the cylinder...unless you guys know ..what is the best ignition for my truck??For some reason I have like...6 wires coming to my ignition..I would love to simplify it..

I tried to polorize my gen today, and it did not throw a spark..But the battery is fully charged,I hit my blinkers and the ammeter moves a bit..with the blinkers.Cant turn the lights on as they are off,along with my fenders. When I have it running i hit the gas and it moves down a bit ..to the left,,when Ilet off the gas the Ammet. needle goes back to the middle??? Do I polorize it with the engine running?

In case you haven't heard, they are now making alternators that look exactly like the old generators. There was an article on this in either Custom Classic Trucks or Classic Trucks a few months ago. I would imagine that they are pretty expensive.

I did hear that...Undecided what i want to do

No you dont need to polarize it with it running. Do you have any electrical shops in your area that test generators and voltage regulators??? Id just bring it in, have them test it and see if they are working properly before I went to much farther. It took less then 5 minutes for the place up here to tell me that nothing was wrong with both of mine...

Not that i know of..I willhave to look into that..

Just did an extensive search in earlier posts Generator VS Alt....I have to say i am leaning towards changing to an alternator. The Gen seems to be High Maintainence,and I also read that not much charge comes from an Idle,which thats all i can do as My truck is on stilts ...Like i said the needle moves when I rev it up...but ...Maybe if you guys can give me the pros and cons ...How many of you guys have gone to an alternator...

I was having charging problems on my '51 while my son was driving it. Since I didn't have a lot of time to trouble shoot it I switched to an AC-Delco 1-wire alternator which in turn eliminates the original voltage regulator. It works great.

That sounds pretty simple Alan.I like that..Like I said, My truck is on Jack stands right now, when I rev it up The needle falls to the neg side a bit, then when I let off it moves back up to the middle. Something else I saw today was my Gas guage does the same thing...I rev up the engine and the needle moves towars empty,when I let off it goes back up to where it should be. Strange but true stories form my truck..Cant wait till I get it on the road..I will be in the forum every night with a new list.ha ha ha

I've had a whole plethora of stock 40s and 50s GM vehicles over the years and experienced all kinds of different anomalies and failures related to generator/regulator systems. I also learned that when it comes to these systems, do NOT tax them by running them at near to or max capacity. Also, always make sure to properly polarize the regulator and generator, and ALWAYS make sure to change the condenser of it's more than a few years old. So many minor things can be done to see that these systems last, but it's often the experience and knowledge that is lacking.

Biggest problem I've found is pitted regulator points caused by not polarizing the generator, running a bad condensor, or a dirty commutator. Also, the generator and regulator have somewhat of a 'symbiotic' relationship with one another... that is, if one fails, it often taxes the other and it fails shortly thereafter.

The original Delco-Remy regulators are very serviceable, and if you have one, best to keep it in service if you can. The new reproduction ones are pretty lame, so don't bother with them.

And don't run A/C with a stock generator. Just don't do it!

Thanks Justin..I did polorize it,My condenser (if I have this part correct) is attached to my gen. When i bought the truck it had been sitting for ??2 years?? but the engine had about 20,000 on a rebuilt.Do I have the condeser part coreect? (location) and should i just go ahead and replace it? gaff

Yes, usually the condenser is grounded to the generator case and has a lead that goes to the (A) Armature terminal. If in any doubt, replace it.. it's cheap insurance. Auto suppliers may have to special order this item, but in a pinch a .5 microfarad 200V capacitor will work. I've done this in applications where looks weren't an issue.

Also be sure that the generator is getting a good ground. Sometimes the gen is mounted through rubber bushings to the mount and the ground cable does not get connected. And of course, make sure the regulator is getting a good ground to the firewall as well. This has tripped me up many times.

Justin Rubsam,

If the truck has no radio, wouldn't the generator mounted condenser be extra baggage and not worth the time to find and install a new one.

Stuart

The condenser serves more than the purpose of radio RFI suppression. Any condenser or capacitor serves the purpose of 'absorbing' energy spikes. This means that it essentially prevents, or at least heavily reduces the amount of arcing between regulator contacts as they rapidly switch on and off. It also helps prevent arcing in the generator brushes. Radio noise is caused directly by this arcing, so noise suppression is actually a secondary function of the condenser.

The condenser connected in the ignition system function in most the same way. First and foremost it prevents the points from arcing every time they open and close, and as stated above, a reduction in arcing not only saves the contact points but prevents noise in the radio.

In some cases, what you'd find is a condenser mounted close to the regulator itself for factory 'radio-delete' cars and trucks... and to further suppress RF interference an auxiliary condenser was installed on the generator. One engine can have as many as 4 condensers: 1 in the distributor, 1 on the positive side of the coil, one on the regulator, and one on the generator armature.

So the moral is don't make the mistake of omitting the all-important condenser just because you don't have a radio! No good can come from omitting these, and it doesn't hurt to have them in absence of a stock radio.

ok...I got all of that,,and actually understood it. I did get spark when i polorized the old generator..I actually cant belive something so old that has had juice running thru it for 52 years is still functioning...

I did a search and found this post with a lot of good information. Question, how can I check to verify if I have a 6V or 12V generator? In addition, how can I verify if I have a 6V or 12V voltage regulator?

Thanks

Formula1 - does the truck have a 6V or 12V battery? check the color of the tags for starters - 12V have a red background, 6V blue or black - the regulator will be whatever the generator is

Bill

Red58,
When I purchased the truck, it came with a few generators, and one volt regulator. I want the original look, but want to make sure their 12v. I have since purchased a 12v battery, but have not installed the wiring harness yet. The starter was painted, and I do not see any color tags. So, I am not sure if I can assume that the volt regulator and generator are 6 or 12v. Is there a way to test??

Formu1a,

What year and make of truck do you have?

A 1945 GMC?

That would have been 6v with positive ground.

See if you can find and numbers/codes on any of your light bulbs.

Tim

Yes, it's a 1945 GMC 1/2 ton. THe truck is a complete ground up restoration, that is on it's 7th year. The guy that I purchased it from began to disassemble, some of the parts,mostly lights. It had a 12v battery in it, and I got the motor running with it originally. Well, long story short, it was a bad chevy 235, so i replaced it with a GMC 302 straight 6. I am replacing everything including the bulbs, which are no where to be found. RIght now, I have the motor hot wired to get juice to the coil, and starter, that's it. The wiring harness is in, but not connected yet. Any help is appreciated.

Formula1,

As you seem to be starting out fresh, I think the best bet, short of finding generator numbers would be to have a auto electric shop spin your generators to find or ID which is 12 volt.

Installing a new 12 volt, negative ground regulator would be cheap insurance that all was compatible. The Carquest number is VR-20...I think.