Running 12-volts through a 6-volt starter

running the 6v starter on a 12v system in the '47 flathead for 3 years and it was at the broiler show.

 

The amperage draw of a DC motor( starter is a DC motor) is inversly proportional to the applied voltage. A 1HP motor at 9 volts will draw 122 amps while @ 12 volts it will draw 95 amps and@ 24 volts it will draw 47 amps. That's one of the reasons auto manufacturers went to 12 volt, they could use smaller wire, which cost less.

 

Hmmm.... I would agree with you if I was engaging the starter longer. However, I only hit the starter motor briefly (each time) and it had no problems turning the engine over (and turns easily by hand). Had I engaged for longer than a brief second, then I would be paying more attention. Not completely dismissing this idea, but being that then engine turns over so easily by hand, I'm finding this hard to accept... at the moment, anyway. Going to to look at starter fitment a little closer before mounting it permenantly.

Let's say for a minute it does have something to do with the starter's relationship to the flywheel (which is not adjustable and the flywheel is also new). What should I look for in terms of fitment? Anything obvious I can check for?

 

It turns over easy fro the FRONT of the motor, but how's it rotating from the flywheel side? I know sounds weird, but if there is a bearing issue you'll only notice it by loading that bearing, which may be loading from the rear of the motor. ..... just side food for the brain, I'm not convinced it's resistance given the timeframe involved, but if that's the case the near lockup conditions could cause issues.

Can you simply pull the starter, leave it connected, have someone keep it steady..... hit it a few times and see if it works properly out of the motor?

 

New guy here but I might have the answer for ya , I worked at a magnet wire factory for a while back in the mid 80's and am wondering if you fed any juice threw the motor bypassing the solenoid . The reason I ask this is if it was rewound there could have been a flaw in the wire itself , we had a few runs where a carbon particle had lodged in the wire , while it would pass voltage it cut the cross section of the wire down considerably making a make shift fuse area . Sounds to me like it might be some defect in the stator windings of the motor .

 

I have a factory 6V Starter on my 331, and run it on 12 volts. It's an unrebuilt original and it's getting a little tired, but if the battery is strong it'll crank right up.

One thing I did do to mine (that you may consider) was add an external Ford 12V starter solenoid like the old "hot start" fix for Chevrolets. I was worried about the heat from the headers, and also the longevity of the factory 6V Chrysler solenoid on 12V. The Ford solenoid basically takes the place of the starter-mounted Chrysler solenoid when added to the circuit.

 

This is a VERY worthwhile thread! Hey, Rich & Scooter, have either of you guys heard of the batteries that were made for a time in the '50s that would START on 12-V, then drop back (somehow) automatically to 6-V?

I never saw one, but my dad worked with a few guys who used and liked them. (I think they became pretty much obsolete after virtually everything on the road was running 12.)

 

Ive seen all kinds of cars and tractors run on 12 volts with the original 6 volt starter. I have never seen it become an issue

 

I used an 8 volt battery in our boat with it's Hercules six. Whirled the old girl over like 12v, the generator kept it charged, and I didn't have to chane the light bulbs. Easy. Any industrial battery dealer has 'em, even Tractor Supply here.

 

I have two International Harvester tractors circa 1955. I converted both to GM 12 volt alternaters. Pertronix ignitions. The six volt starters have lasted more than twenty years. They start instantly, instead of the old six volt grinding,choking and praying!!!

 

That was SOP on outboard motors for quick starts.

 

Yes! This will be done for sure before it gets mounted back on the engine.

Interesting. To the best of my knowledge they didn't rewind it though. If they did, they must be cheap and quick because I paid a very reasonable price to have it rebuilt and they did it in under a week.

I like this idea. Do you have a part number for the Ford solenoid? Also, educate me for a second... How does the starter gear engage if I remove the solenoid assembly from the starter assembly? (sorry if that's a silly question)

 

hooking 12 v wont hurt it. sometimes I hook up 24 v to a stuburn 12 v system, you should hear the starter whirl then!

 

You leave the solenoid mounted to the starter, but it isn't under load anymore...it ends up working just like a Ford does. I'm sure someone else can explain it better than I can.

Maybe this will help...

http://www.chevyhiperformance.com/techarticles/148_0312_chevrolet_no_start_fix/index.html

Solenoid is just a plain ol' Ford Solenoid. Any good parts guy will know exactly what you need.

 

That's impossible... You would have to use a relay to electrically link two 6v batteries in series to do that. You can create a multi voltage system. There is no such thing as a multi voltage battery.

As for the original problem, your starter was probably going to fail with or without the three bumps. Count your blessings it was at home. Use a 12v Ford solenoid like Bass mentioned. Best remedy.

 

Aaaa!! Totally get it!! Thanks man!! Seems like a GREAT solution!! I'm going to get right on it!

 

Just one more experience, no new ground being plowed here. I've been running my gradfather's (I'm just the caretaker) 1948 Ford 8n tractor on 12 volts since I got it in 1973. the 6 volt generator will not keep the battery fully charged but putting it on the charger in the spring will usually keep it running well into the fall. I use it a couple of times a week and the origional starter is still going strong.

Frank

 

This has turned out to be a great discussion. I appreciate all the info. Keep going, I'll keep reading...

 

One tecnical thing is when the starter spins faster the impidace will be higher and less ampage
if you use a 12V starter on 6V it will be overloaded and burn verry quick

 

Scooter, I ran '48 Willys PU with the 6 volt starter and a 12 volt battery for years. As far as I know the guy that bought it still is using it that way. Old style floor mounted starter switch.

I also agree with 440 RR about the second solenoid. It doesn't affect the heat applied to the GM solenoid. When I was selling parts we had a roundy-pounder do the same thing. He also wondered why it didn't help at all. He also did it because "everbody else is".

 

My dad's got a original 41 stude. Everything is 6 volt. We recently put a 12 volt bat. In the trunk just to crank the starter. Our local starter repair guy said it would work just fine as long as you didnt crank on the starter to long.

 

Alright!

 

Thanks for clarifying my original statement. Put it on top, put it on the bottom, hang it off the side: call it the "Back to the Future-Flux Capacitor" if you want, you're still using a relay to connect two 6v batteries in a series to create a momentary 12v condition...

 

Oofa... come on guys. Point made. Please resort to nasty grams through PM's. Let's not ruin a good discussion. This thread has been really informational so far.

 

QUICK UPDATE!

I'm going to pick up the starter right now. The guy said there was a lead wire inside the armature of the motor that was completely melted away. I'm assuming this is a fusable link of sorts to protect the armature of the motor. Good assumption?

If I keep applying 12-volts to this thing, any bets on rather or not it will keep melting away?? Again, hard to believe this would happen so quickly. I'm worried now, though. Anyone else experienced this? Since I don't know the history of the starter, I don't know rather or not this lead wire was already on the way out or not. Total gamble at this point.

Being that I don't really have any other options other than having the starter rewound (which require paying someone to do it anyway), I guess I'll give it a whirl again and see what happens. I'll check fitment and clearances before fully mounting it solid.

Frustrating. I just want to fire this motor.

 

I have run 6V starters on 12Vs many times. If you have the engine tuned correctly it should start almost instantaneously. No cranking required. I have had carb and ignition problems in the past and burnt up 6V starters of unknown ages. The starters were probably 30 years old or better when I was not thinking and kept trying to sort out the problem while cranking it over checking for spark etc. If you are using 12V on a 6V starter just be aware that it won't take the abuse that your daily driver might put up with. Keeping the engine in tune and a little common sense will keep it going for years.

Both times it was my stupidity that caused the starter to fail. You'd think I'd learn the first time. Both times I had the generator shop use 12V windings to rebuild the 6V starter.

 

Important question:

I was making an assumption about Chrysler electrical systems. Were '51 to '56 Chryslers positive ground or negative ground?? I've been making the assumption all this time that they are negative ground. Is my assumption correct??

 

So if the chassis/engine were considered ground and are POSITIVE, shouldn't I be wiring the starter differently??? Or are you saying the engine itself was an isolated component and treated as a NEGATIVE ground?

Bujeezow... I hate wiring.

 

Am I over-thinking this? Do I just wire it as normal and go? I want to get this thing back in the car tonight and fire it up. I just want to make sure I'm on the right track! I don't want to burn up another starter.

BTTT! Hopefull for some quick knowledge! Don't want to burn this thing up!

 

Been a few years but I have an old loader that had a FH Ford, 6 volt, positive ground. I believe that all we did was put in a 12 volt, wire for negative ground. Worked for years until the FH blew up.