Hot coil update

[super99]

I changed the coil to one with an internal resistor, starts good and runs good. I tested the old and new coil per You Tube video. They are close to the same readings, don’t know whether to save it or pitch it. Not sure the coil was the problem but I’d changed the condenser and coil was the next step. Let it run for close to an hour and then drove it around the block , about 4 miles, and checked coil temperature with the infrared thermometer and it was 135 degrees. Don’t know if that’s good or bad.Guess I’ll find out. Thanks for the help , Chris

 

[wore out]

I changed the coil to one with an internal resistor, starts good and runs good. I tested the old and new coil per You Tube video. They are close to the same readings, don’t know whether to save it or pitch it. Not sure the coil was the problem but I’d changed the condenser and coil was the next step. Let it run for close to an hour and then drove it around the block , about 4 miles, and checked coil temperature with the infrared thermometer and it was 135 degrees. Don’t know if that’s good or bad.Guess I’ll find out. Thanks for the help , Chris View attachment 120336View attachment 120335View attachment 120334View attachment 120333

WHY do you have your meter set on the 20K Ohms range while "testing" a coil primary resistance of under 5 Ohms?

 

[super99]

WHY do you have your meter set on the 20K Ohms range while "testing" a coil primary resistance of under 5 Ohms?

The guy on U Tube said to set it om 200 and touch the probes together and it should read zero, if not, move indicator to the next higher setting which I did and the it read zero.

 

[used red MN]

From what I saw in the other post you said you “it burned my finger” I would be curious to know what the temp of those were with the temp gun. I am thinking yes they were hot, but maybe not “too hot”? A guy with tender hands would probably get burned at 135F. Well hopefully you have it fixed.

then drove it around the block , about 4 miles

Must be a city boy, most farmers would call that a “section”

 

[Janicholson]

Two items. a meter such as yours should be set on the range of resistance expected. In this case RX200. RX1 would be best. Touch the needles together then rite down the number. then test the sample (coil) and subtract the original number to get the difference. (really good meters have RX1 settings and read close at the 1 to 5 ohm level). The youtube guy was all wet.
As I stated in the earlier post, there are no actual resistors in the coils with 3+ ohms. They are just made of thinner wire, and more of it. Like a 12 v bulb rather than a 6 v bulb. Jim

 

[Fixingfarmer]

There should be even a 20 ohm lowest setting I can’t see the rest of the switch. For everything I can think of on old tractors 99 times out of 100 (I can’t even think of a time I’ve measured over 20 ohms and not just called the subject testing open or a failed wire that needs replaced) that is sufficient

The YouTube guy must have had a switch fail on his meter or something weird happen once to be giving out that advice that is a new one for me as well.

Glad it’s running!

 

[wore out]

The guy on U Tube said to set it om 200 and touch the probes together and it should read zero, if not, move indicator to the next higher setting which I did and the it read zero.

Well, DON'T leave that ewetoob guy a "like" 'cause he has no idea what he's doing!

 

[JMOR]

definitely a BAD place to go if looking for real information!!!!!!!

kinds like looking for something to eatin the toilet!

 

[Bob Bancroft]

From what I saw in the other post you said you “it burned my finger” I would be curious to know what the temp of those were with the temp gun. I am thinking yes they were hot, but maybe not “too hot”? A guy with tender hands would probably get burned at 135F. Well hopefully you have it fixed.


Must be a city boy, most farmers would call that a “section”

Depends on location. Luckily where I am located there are plenty of blocks. No sections. But there's lots of farmed land which can't be laid out in any neat pattern.

 

[buickanddeere]

For the next test . Measure the current through the coil primary windings with the points closed .
btw is the battery connected pos or neg to chassis ?
On the tractor , which coil terminal is connected to the points closed?

 

[Geo-TH,In]

I changed the coil to one with an internal resistor, starts good and runs good. I tested the old and new coil per You Tube video. They are close to the same readings, don’t know whether to save it or pitch it. Not sure the coil was the problem but I’d changed the condenser and coil was the next step. Let it run for close to an hour and then drove it around the block , about 4 miles, and checked coil temperature with the infrared thermometer and it was 135 degrees. Don’t know if that’s good or bad.Guess I’ll find out. Thanks for the help , Chris View attachment 120336View attachment 120335View attachment 120334View attachment 120333

I recommend you put the coil and ballast in series, connect it to 12v and measure the amps with your meter which has a 10 amp range.
Then Measure the voltage drop across ballast and coil. That will tell you more than using the ohmmeter.
Please post your results for both coils.

 

[John T]

Here late but its been my experience cheaper VOM meters aren't real accurate when it comes to low resistances. If you had an ammeter and voltmeter to accurately measure coil voltage and amps through it with points closed it should be no more then 4 amps then use R = V/I to find resistance. (I agree with neighbor George !!!!!!!!!!!!!) ............The TOTAL of coil plus any external ballast resistance needs to be 3 ohms so as not to exceed 4 or so coil amps,,,,,,,,,not burn the points, and not overheat the coil. Location of the coil plus its metal to metal mount can influence its temperature. Typical full true 12 volt coils are around 3 ohms.

John T