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12 volt or 6 volt for buzz coils

Will

Registered
I know this has been brought up once before but I thought I’d throw it out again. Looking for comments on the voltage for buzz coils. I use garden tractor batteries that are 12 volt just because they will last a whole weekend running time without a recharge. A fellow I met at a show last summer said he would never use 12 volt thus he uses only 6 volt.


Will
 
T

Tom Werner

Guest
Will, They were wound for 6V operation.. 12V will only cause them to fail prematurely. Change batteries or add some resistance to drop the voltage to
Tom W in WI
 

Mike Monnier

Hoarder
Age
43
Last Subscription Date
12/18/2019
You should be fine on 12V as the T did not have a voltage regulator. Thus, the coil could see up to 40V in operation if I remember correctly. There should be a fairly lengthy discussion of this in the archives.
 

David M. Lyon

Subscriber
Last Subscription Date
12/12/2020
I don't think it matters...They seem to work equally well on 6 or 12 volts...I Have used 12 volts for years and have never had a problem out of one..They only make contact for a millisecond, so it can't hurt them....Just my opinion!...As Harry says."Your mileage may vary" :crazy:

David M.
 

Bob Fultz

Registered
Last Subscription Date
03/08/2010
I use an old Chrysler ignition resistor (Echlin#ECHICR23) from NAPA. It puts out 12volts to start and then drops to 6-8 volts while running. I'm no expert on electronics but what can it hurt. It goes in the + wire between the battery and coil.
 

Craig A

Moderator
Staff member
Age
68
Last Subscription Date
12/20/2015
The Hart Parr 30-60 and others use a highbar KW continuous output mag for buzz coil ignition power after a battery start. It puts out between 12-14 volts and works just fine.
I suppose if you want to crank your butt off because of a weak spark you can get away with 6 volts....................I know I won't bother with 6 volts anymore.
To each his own~~~~~~~~~~~~~~~~~~~~~~
 
I'm thinking I read or was told the Fordson tractor and the model A car generated 27 or so volts to the buzz coils so 12 volt certainly isn't anywhere too much if I read this right? I always recommended 12 volt for buzz coils and 6 volt for low tension coils. I have seen the low tension coils heat up from a 12 volt battery being used on them. This also could be the number of windings in the coil causing this and possibly a heavy coil might hold up ok with 12 volt. Please fine tune this response as I don't want to mis-lead anybody. Ed
 
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garry brown

Guest
Related to the 6 Volt - 12 Volt discussion I would like to hear any comments on something my friend told me. I don't know much about electricity but he said that if you use a 12 Volt battery on igniter - low tension style ignition the higher voltage potential will change the timing (makes it more advanced). Is that true? Is that significant?
 

Junkologist

Subscriber
Last Subscription Date
12/28/2019
I can't see how a voltage increase could advance the timing on an ignitor fired engine. The moment of ignition is when the ignitor points snap open. You could have 2 volts or 1000 volts, but the ignitor points are still going to snap open at the same moment.

Mike
 

Harry

Administrator
The only thing that 12 volts might be good for on a low tension ignitor coil is to melt it. The extra voltage causes extra current to flow. This might produce a hotter spark, but if your points are closed when the engine stops, you can be assured of a melt down inside your coil.

Also, some ignitors used with magnetos are adjusted to be normally closed and then open at the instant that spark is wanted and then close again. This would most assuredly cause a coil melt down if you use that ignitor on a 12v battery.

Ignitors that are adjusted to be normally open and then close for the instant just before spark is wanted, draw much less power and therefore make much less heat in the coil. You might get away with 12 volts on this setup as long as the points don't happen to be closed during shut down. The resistor idea will also help reduce current flow.

As to 12 volts on a buzz coil, that's most likely fine. Its duty cycle is shortened because of the rapid on/off function of the vibrator.
 

BWegher

Registered
Age
63
Good advice so far.
I've seen some buzz coil circuits in the old books. Some use 6 volts. Also, you see 8 volts, that is four dry battery cells, at 2 volts per cell.
If you have a good condenser, 6 volts work fine. It's also important to back off on the point tension nut until the engine starts to misfire, then back down about 1 turn. Too many people crank down on the nut too far for no good reason.
 

ErikG

Registered
Age
52
I asked an engine guru this same question last fall when I saw he had a ford coil hooked up to a 12 volt battery (high tension). He said as long as it was hit-n-miss governed he used 12 volts. But not for throttle governed which would fire every time. I believe he said heat was an issue.


Erik Grund
 
A

Arthur

Guest
I don't know much about this 12 Volt and a buzz coil, but I owned a T model back in the late 40's and it would start fine on 6 Volt. What I remember most about the ignitionn was the coil box was under the dash, and at night it would lite up the floor boards pretty good on batt., but when it was switched to magneto it looked like the the whole mess under the dash was on fire. I have often wondered how much Voltage was coming from that mag.,it had to be more than the batt. because it was so bright. I think some of the boxes had a cover,but mine didn't, I reckon someone threw it away. Dogonnet I almost told my age. Arthur
 

Ken Majeski

Subscriber
Last Subscription Date
12/10/2019
Well, a Really Good Model T mag will put out up to 38 volts or so at high RPM but it is AC instead of DC. You can Really feel a 6 volt T come to life when you change over to Mag... :) 12 volts DC will not harm a properly adjusted T coil. Problem is... not all Buzz coils are T coils... :( Some coils are made for Gas engines and were made to work on about 6 to 8 volts DC. But they probably are the minority these days.... Henry made over 15 Million T's and they each had 4 coils.... No Wonder there are so many laying around....
 

bimjy

Registered
Age
63
Last Subscription Date
11/21/2013
I too put the Chrysler resistor on my buzz coil ignition on my oilfield engine. It will not start on spark plug. I can fire engine off on hot tube an then switch over to spark plug and shut off hot tube and it will run. After reading all these very informational threads I am now wondering if I could some how switch coil to 12 volt to help start engine(hotter spark???) and then switch back to resister to extend coil life. Any ideas? Thanks to all!! Jim
 

Ralph Leonard

Registered
Age
90
bimjy said:
I too put the Chrysler resistor on my buzz coil ignition on my oilfield engine. It will not start on spark plug. I can fire engine off on hot tube an then switch over to spark plug and shut off hot tube and it will run. After reading all these very informational threads I am now wondering if I could some how switch coil to 12 volt to help start engine(hotter spark???) and then switch back to resister to extend coil life. Any ideas? Thanks to all!! Jim
Jim, connect a switch in the battery lead to the buzz coil. Then connect your resistor across the switch terminals.

Switch on for high voltage (12). Switch off (resistor in circuit) for lower voltage. 40 feet of 24 gage wire will drop the 12 volts to about 6 volts across the coil. Its a good battery saver for using gel cells. Works well for ignitor coils also ;)
 

Elden DuRand

In Memory Of
Age
78
Last Subscription Date
12/22/2017
There's no big problem running a "T" coil on 12 Volts except that it will get a little warmer and will tend to burn the points faster. I'm not sure that the output voltage would be a whole lot higher with 12 Volts as compared to 6 Volts because the magnetic field has to build up to the same intensity to pull the points open no matter what voltage is applied.

Another way to drop the voltage to the coil is to use a 12 Volt brake light bulb (draws about one amp) in series with the coil.

I use this with a 12 Volt battery on the low-tension coil for my F-M Jack of All Trades. Works like a champ with the advantage that you can tell if the ignition's on by closing the ignitor points and looking for the lamp to light-up.

Take care - Elden
 

bimjy

Registered
Age
63
Last Subscription Date
11/21/2013
Thanks for all this great info. Can't wait for spring to get it out and do all the modifications I been reading about in this forum!! Jim
 

Anthony J. Wiegand

Registered
Age
30
I haven't had any trouble using 12 volt batteries. I use 12 volt drill batteries because they last a long time while running. They are also rechargable. I have mine hooked up to a hit and miss engine. I haven't loaded my hit and miss engine up so it fires each time so I dont know how long they would last under that kind of load. There's my 2 cents worth.

Regards, Anthony:wave:
 
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