|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
04-13-2014, 08:51 AM | #1 |
Senior Member
Join Date: Jul 2012
Location: France
Posts: 111
|
12 volt coil on a 6 volt engine
Hello,
My 6 volt coil failed and I just have a 12 volt coil to run tomorrow morning. What do you think about that ? Does it work ? Very well ? Limits ? Thank you |
04-13-2014, 08:58 AM | #2 |
Senior Member
Join Date: May 2010
Location: capemaynewjersey
Posts: 653
|
Re: 12 volt coil on a 6 volt engine
You should a ballist resster in line to reduce voltage
|
Sponsored Links (Register now to hide all advertisements) |
|
04-13-2014, 09:05 AM | #3 |
Senior Member
Join Date: Sep 2011
Location: Luck WI
Posts: 550
|
Re: 12 volt coil on a 6 volt engine
No extra ballest resistor needed. It will work but will have a lower output voltage to plugs, engine may not run as well, but if you have do not have a 6 volt coil it is worth trying.
__________________
Jon "If you choose to not decide, you still have made a choice!" RUSH Don't tell me what you know..... Tell me what you have done. |
04-13-2014, 09:35 AM | #4 |
Senior Member
Join Date: Jul 2010
Location: Cow Hampshire
Posts: 4,188
|
Re: 12 volt coil on a 6 volt engine
I think that's the other way around. Using a 6v coil on a 12v battery requires a resistor - a lot of 12v coils include a resistor (put there to prevent burning up the coil should the engine stop with the points "on.") but many don't.
I say just do it. Otherwise known as "nike-it." If it works - it works. If not you can't hurt much. Joe K
__________________
Shudda kept the horse. |
04-13-2014, 09:42 AM | #5 | |
Senior Member
Join Date: May 2010
Location: Young Harris, GA
Posts: 1,819
|
Re: 12 volt coil on a 6 volt engine
Quote:
Can you measure the resistance with an ohm meter across the the 2 coil posts? Some "12 volt coils" read out at about 1.5 ohms and require an external ballast resistor to be able to use them on a 12 volt car. You can run a 1.5 ohm "12 volt coil" on a 6 volt car without a ballast resistor and it will run great. Some "12 volt coils" read out at about 3 ohms and can really only be used on a 12 volt car. The spark out of this "12 volt coil" when used on a 6 volt car will be very weak. The car might start but you won't like how it runs with the weak spark. If you have a NAPA near you, you can get an IC-12 coil for your 6 volt car that will be around 1.5 ohms. Lots of confusion around coils and volts. I hope this helps.
__________________
Jim Cannon Former MAFCA Technical Director "Have a Model A day!" |
|
04-13-2014, 11:23 AM | #6 |
Senior Member
Join Date: Jul 2012
Location: France
Posts: 111
|
Re: 12 volt coil on a 6 volt engine
Sponsored Links (Register now to hide all advertisements)
I don't have an ohm meter. My 12 volt coil ( not damaged ) is propably 50 years old. Perhaps, last chance : I'll try to call an old man who owns old cars. |
04-13-2014, 11:40 AM | #7 | |
Senior Member
Join Date: Jul 2010
Location: Cow Hampshire
Posts: 4,188
|
Re: 12 volt coil on a 6 volt engine
Quote:
Yeah. I know. They're offshore sourced. And they're not that accurate. And they're not that well made. But FREE is FREE. At least until the end of the month of April - or while supplies last. See attachment below Joe K
__________________
Shudda kept the horse. |
|
04-13-2014, 11:42 AM | #8 |
Senior Member
Join Date: Jul 2012
Location: France
Posts: 111
|
Re: 12 volt coil on a 6 volt engine
Shame on me !
|
04-13-2014, 12:21 PM | #9 |
Senior Member
Join Date: May 2010
Location: Largo Florida
Posts: 7,225
|
Re: 12 volt coil on a 6 volt engine
Many [ but not all] internally ballasted coils will have markings as such on the outside.
Your 12v coil should work fine if not internally resisted. Once you get ahold of a volt meter, regardless of 6 or 12 volt systems you only want 6-8 volts feeding the points. |
04-13-2014, 03:39 PM | #10 | |
Senior Member
Join Date: May 2010
Location: Young Harris, GA
Posts: 1,819
|
Re: 12 volt coil on a 6 volt engine
Quote:
Just use it! It will cause no harm. It might just run poorly. You'll know soon enough.
__________________
Jim Cannon Former MAFCA Technical Director "Have a Model A day!" |
|
04-13-2014, 03:55 PM | #11 |
Senior Member
|
Re: 12 volt coil on a 6 volt engine
I agree with Jim. How many old cars (12v) had an external resistor.
__________________
What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II |
04-13-2014, 05:11 PM | #12 | |
Senior Member
Join Date: May 2010
Location: Largo Florida
Posts: 7,225
|
Re: 12 volt coil on a 6 volt engine
Quote:
Most. Chrysler mainly with their famous external ballast resistor, Ford had it both ways as did GM using either a mounted resistor as Chrysler, a resistor wire or resistor coil. Some coils were noted as such but not all. Many folks then were not aware of the resistor wire. |
|
04-13-2014, 05:24 PM | #13 | |
Senior Member
|
Re: 12 volt coil on a 6 volt engine
Quote:
__________________
What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II |
|
04-14-2014, 10:37 AM | #14 |
Senior Member
Join Date: May 2010
Posts: 203
|
Re: 12 volt coil on a 6 volt engine
I've run any number of 12v coils on 6 volts. They always worked fine. A guy has to learn how to do things like that if you want to save yerself in a squeeze. 50+ years ago, we didn't have money for a new coil. We had to make do. Go for it!
|
04-14-2014, 12:17 PM | #15 | |
Senior Member
Join Date: May 2010
Location: St Charles , Missouri
Posts: 1,998
|
Re: 12 volt coil on a 6 volt engine
Quote:
Like Joe said... I would get a meter and measure it to know what you have... it should be between 1.2 and 1.5 ohms. If it is it should be fine. I gave a voltmeter and troubleshooting seminar at the MARC Membership national. All the guys in our group picked up the free meters from Harbor Freight when they could, so everyone attending the seminar went home with a free meter from the seminar. They are not the best, but will get the job done. Again, get a meter and check it ( all wires off) and see what the ohm reading is. Good luck! Larry Shepard |
|
04-17-2014, 04:43 PM | #16 |
Senior Member
Join Date: Apr 2014
Posts: 709
|
Re: 12 volt coil on a 6 volt engine
My 75 MGB is a 12 volt car with a 6 volt coil. There is a resistor wire which is shorted out by an extra contact in the starter solenoid when you turn the key. This puts 12 volts to the coil to warm up the spark for starting. Many cars had similar setups hence the external resistors. Not many people know that.
Ian |
04-17-2014, 05:21 PM | #17 |
Senior Member
Join Date: May 2010
Location: Asheville,NC
Posts: 3,104
|
Re: 12 volt coil on a 6 volt engine
According to my parts man, all coils are 6 volts. The ones marked 12 volts are internally ballasted to reduce the voltage to 6 and the ones without the internal ballast will be marked to use an external ballast resistor. Use the coil and you may never change it.
__________________
http://www.model-a-ford-4bangers.com/ |
04-17-2014, 07:33 PM | #18 | |
Senior Member
Join Date: Nov 2011
Location: Dayton Oregon
Posts: 318
|
Re: 12 volt coil on a 6 volt engine
Quote:
__________________
Hotrods don't have valve covers |
|
04-18-2014, 04:15 AM | #19 |
Senior Member
Join Date: May 2010
Location: VA
Posts: 1,410
|
Re: 12 volt coil on a 6 volt engine
|
04-18-2014, 08:07 AM | #20 |
Senior Member
Join Date: May 2010
Location: Long Island, NY
Posts: 3,465
|
Re: 12 volt coil on a 6 volt engine
Until High Energy Ignition (HEI) came out in the late 1960s, 12-volt coils were usually 8-volt coils as were many of the 6-volt coils. If the 12-volt coil is pre-HEI, it should work with an input of 6 volts.
Early 12-volt ignition systems used an 8-volt coil. When the ignition switch was turned to the START position, 12 volts went to coil to provide a higher voltage spark. When the switch went into the RUN position, a resistor or resistance wire dropped the coil voltage to 8 volts.
__________________
Bob Bidonde Last edited by Bob Bidonde; 04-18-2014 at 08:14 AM. |
|
|
Sponsored Links (Register now to hide all advertisements) |
|