Rookie Question re: Generators

[ChrisMinelli]

Hello, this is my first post.  I’m interested in buying a 52 Cranbrook a few towns over.  It will be my first classic (and actually my first American car).   The owner told me the generator is faulty and should be replaced prior to driving it the 40-odd miles to my house. 
 

I’m hesitant to believe that, given the limited knowledge I have of generators vs alternators.  If I get the car running and I don’t want to use the lights or radio, what else could possibly need electric in an older car?  It’s not like it has an onboard computer like my Honda.  I’m afraid this guy just wants me to pay him to put in a new generator — something I’ll do myself.  
 

Apologies in advance of this is a dumb question.  I’m very familiar with Japanese cars but I’m a millennial and don’t even own SAE wrenches.  I’m hoping to learn though.  Thanks in advance.  

[Jerry Roberts]

There could be very many things wrong with a 1952 Cranbrook . Don't count on just replacing or rebuilding only the generator . Another main part of the charging system is the regulator . I would be very wary of trying to drive an unknown car of that age on a 40 mile trip .  

[keithb7]

Jerry makes a great point. Seems there are about 500 things that are often awry when we buy old vintage cars. Tires, brakes, steering components,  engine overheating, fuel pump issues, carb issues, poor electrical connections and grounds. Poor ignition system, points, coil, etc..Wheel and transmission bearings. Engine condition. Clutch, tranny diff, and more...A whole lot more than just a generator. Heck I addressed most all of those issues mentioned in my '53. I still think about a backup plan and preparations for any 40 mile trip I go on.

 

Saying that, if everything checks out great and you have good reason to believe every other system in the car is ready and reliable for a 40 mile trip...Ensure you have a good strong 6V battery. Turn everything off and drive it home. You could always pack a spare 6V battery and a wrench just in case. Put the spare battery in and keep driving, if needed.

 

If the generator is seized up and won't turn, well that's a whole 'nother problem. You won't be going far without a drive belt.

Edited November 27, 2019 by keithb7

[allbizz49]

Bring a volt meter and check yourself. If it's charging like it's supposed to, go for it. I drive a 60 year old truck every day. I have rebuilt the suspension, steering, brakes and engine but only as needed. These cars are so basic and easy to work on, don't sweat it. Just make sure it stops and steers like it should and do the 40 miles. That really isn't that far. I used to drive my truck 110 miles every day to work and back. Good luck and have fun.

[TodFitch]

I've known people who were on the road in old cars to drive all day (hundreds of miles) with a dead generator. The ignition system doesn't draw all that much power. Heck, I had the alternator on a '82 Plymouth go out in the middle of the night driving I-15 west/south of Las Vegas. Pulled over and slept until daylight then drove the remaining 150 to 200 miles home on the battery alone. Not sure I'd attempt that on a more modern car with more electronics, but even that '82 had an ECU.

 

But the other comments about the myriad things that could go be wrong with an unknown to you car should be heeded. If you are very confident that you have the tools and knowledge to do a decent safety check on the car before driving it (especially brakes, steering and suspension) then it could be an adventure. If you have any doubts about that, then getting it trailered to your house would be the wise decision.

[Merle Coggins]

I agree that if the generator isn't producing a charge voltage/current then it would be fine to drive home, provided the battery is fully charged. However, if it is a failed bearing/bushing in the generator I wouldn't want to drive it much. You may be able to add more oil to the bushing oil cups to give it a fighting chance, and loosen the belt some. However, you still need to be able to drive the water pump.

So, it all depends on the type of failure to the generator. If you can get more detail on that you can then make a better decision.

[Plymouthy Adams]

I see it as this...if you wish to drive the car...is the car currently registered and licensed, in other words, has it been on the road and this is just a recent failure.  Second, without tools to work on the beast, you taking a big change driving albeit a short jaunt without tools at hand.  Remember also that every time you start the battery without replenishing it with the generator along with every time you use the brake or turn signals (lights) you lessen the distance you can travel as the ignition needs approx. 5 amps steady supply to supply spark.  I would not be near as concerned for the generator as I would for brakes.....lighting and then tire condition.  Now to part two.....what kind of guy advertises a car for sale with known defects then try to charge the buyer for those repairs before selling the car given it as he states, simply the generator and an easy fix.  

[Loren]

Years ago when I was younger and stupider a guy offered me a 1968 SAAB 96 V4 that had sheared off the oil pump drive shaft. Not owning a trailer or a vehicle to tow it, I decided to just drive it home.

I put two extra quarts of oil in the crankcase and set off with ZERO oil pressure.

The trip was from Lancaster to Burbank, CA just about 100 miles.

It made it without a problem!

On tear down I expected to replace all the bearings and maybe more.

All that was required was a new oil pump driveshaft and a pan gasket!

Maybe I was lucky, I don’t know.

I’ve since decided it’s not worth the anxiety, besides I have a trailer and a truck now.

[desoto1939]

There have been many great posts regarding your issue.

 

BUT, since you stated that you do not own any wrenches and this seems to be your first experience with an old car and you sound like you have not a lot of knowledge on this car  then either have someone follow you home in another car incase you have a breakdown on the road. or get someone with a trailer to bring the car home the 40 miles.

 

If you belong to an automobile club like triple AAA or some other car serviceing company, then you could start on your way home then if you have a problem call them to have the car flatbedded to your home. Most companies havea 100 mile range.  But have a chase car follow you with the old car that you just purchased.

 

I would drive the car around the block at the current location to make sure it stops and starts the brakes work not fuel issue, have brake lights and headlights.  Do some leg work prior to taking it home with you.  If there are issue then they can be fixed at a local garage if the current owner has a mechanic that he knows.

 

Welcome to the club you will learn a lot about an old car.

 

Rich Hartung

desoto1939@aol.com 

[ChrisMinelli]

A quick update — the car drove like a dream.  I had the generator rebuilt and have been doing little things to it since getting it home.  Tonight I was driving it and the engine had quite the backfire and the whole thing just died.  Now I have a project!

 

(Also, I didn’t want to imply I didn’t know what I am doing.  I’m very familiar with Honda’s and the like.  I just didn’t own any SAE / inch tools until recently because they are useless in Japanese repairs). 

[keithb7]

Backfire and it died? Fun times! Do you have some ideas and a plan?

[Andydodge]

Chris.......Welcome aboard!........sounds like it isn't too bad a car......any pics...........and I'd suggest getting some SAE/Imperial tools.............real measurements......what are those things at the end of your legs?........metres or FEET.........lol.................regards from Oz.......Andy Douglas  

[greg g]

Compression test is likely in your future.  Make sure you don't screw the gauge business end in any deeper than the spark plugs and goes in. Plugs are over a valve, contact between valve and tester is not a desirable prospect.

[Sam Buchanan]

3 hours ago, ChrisMinelli said:

A quick update — the car drove like a dream.  I had the generator rebuilt and have been doing little things to it since getting it home.  Tonight I was driving it and the engine had quite the backfire and the whole thing just died.  Now I have a project!

 

(Also, I didn’t want to imply I didn’t know what I am doing.  I’m very familiar with Honda’s and the like.  I just didn’t own any SAE / inch tools until recently because they are useless in Japanese repairs). 

 

For the engine to suddenly die it must be a problem with either fuel or fire. My first thought would be to verify spark is occurring at the correction time. Most likely a simple fix (the points)....then back to enjoying your ride! 

Edited December 22, 2019 by Sam Buchanan

[Greg51T&CWagon]

Check to make sure the distributor is snugged up tight, that it can't rotate. 

[John Reddie]

Welcome.

  After verifying that you have fuel delivery to the carb, I would take a jumper wire and bypass the ignition switch and see if it improves. I say this because the '48 Dodge I once had did what you said, backfired and died. The trouble was a defective ignition switch. Assuming that your Plymouth is still 6 volt and positive + ground, connect the small jumper to the negative - battery terminal and the other end to the negative - terminal on the coil. Don't leave it connected very long when it is not running or your points will get burnt. Best of luck to you.

John R

[James_Douglas]

Check the distributor vacuum advance. Often these will die and when you put you foot into the throttle hard, it will backfire and die.

 

James.

[greg g]

Quick test for generator voltage regulator for vehicles with ammeters;

With the engine at idle connect the field terminal of the generator to ground.  The field wire is the smaller diameter terminal stud on the generator body. Rev the engine to about 1200 rpm.  Observe the ammeter.  If it pegs to the plus side, the gennerator is working.  If it doesn't peg, that indicates the Gen is not working.  If it does peg this indicates regulator cut out circuit is not operating as it should.  If the generator is working, leave the jumper connected, turn on the headlamps and heater fan and drive where you need to go. This will keep the battery from over charging and the Gen from overheating till you get home or to the repair shop. It may be a simple fix, new brushes for the Gen or cleaning and adjusting the contact points under the VR cover.

 

New fully charged batteries should only show a positive charge on the ammeter for about 10 pop to 15 minutes of driving or until the Genny restores the power that starting the car has used. The ammeter should then drop down to a minimal plus charge unless another heavier load is applied and draws the battery down.

Edited December 22, 2019 by greg g

[ChrisMinelli]

Wow — I appreciate all the great information and advice!  I have found a good place to learn it seems like.  I suspect a problem with the generator, because the car was dead yesterday but fired up fine today after the battery charged.  I suspect bad generator -> battery was powering the spark plugs -> battery drained -> sparks didn’t fire in sequence -> backfire and stall -> no power to restart.   I’m going to run some tests with my multimeter this afternoon.  (The wife wants me to rake leaves first... you know how it is). 

[Merle Coggins]

Raking leaves in December...  How ‘bout that... my December outdoor chores usually involve a shovel, or snow blower. ?

[Sam Buchanan]

3 hours ago, greg g said:

Quick test for generator voltage regulator for vehicles with ammeters;

With the engine at idle connect the field terminal of the generator to ground.  The field wire is the smaller diameter terminal stud on the generator body. Rev the engine to about 1200 rpm.  Observe the ammeter.  If it pegs to the plus side, the gennerator is working.  If it doesn't peg, that indicates the Gen is not working.  If it does peg this indicates regulator cut out circuit is not operating as it should.  If the generator is working, leave the jumper connected, turn on the headlamps and heater fan and drive where you need to go. This will keep the battery from over charging and the Gen from overheating till you get home or to the repair shop. It may be a simple fix, new brushes for the Gen or cleaning and adjusting the contact points under the VR cover.

 

New fully charged batteries should only show a positive charge on the ammeter for about 10 pop to 15 minutes of driving or until the Genny restores the power that starting the car has used. The ammeter should then drop down to a minimal plus charge unless another heavier load is applied and draws the battery down.

 

If you are not concerned about keeping the car "original" an internally regulated (one wire) alternator is a great upgrade and will solve any genny or regulator problems. The alternator on my '48 will bring the ammeter needle back to near zero in less than a minute at idle after a cold start. Also, go ahead and install the proper size battery cables if the ones you have are smaller than the ones in the photo.

 

[Sniper]

You have 6v cables on a 12v system,  not an issue other than overkill.  Running 12v cables in a 6v system makes them undersized though, yet another hack the PO's mechanic did on my 51.

 

As for alternator swaps, I prefer my Mopar to remain as much Mopar as I can. 

[Sam Buchanan]

Just now, Sniper said:

You have 6v cables on a 12v system,  not an issue other than overkill.  Running 12v cables in a 6v system makes them undersized though, yet another hack the PO's mechanic did on my 51.

 

As for alternator swaps, I prefer my Mopar to remain as much Mopar as I can. 

 

 

My car is 6v.

[Sniper]

Where did you find a 6v single wire alternator?

[Sam Buchanan]

39 minutes ago, Sniper said:

Where did you find a 6v single wire alternator?

 

https://www.ebay.com/str/HowardEnt?_trksid=p2047675.l2563

Edited December 22, 2019 by Sam Buchanan