Testing Resistance On New 6 Volt Coils

via YouTube Capture

[utahutes]

When you test the secondary resistance readings, look above the reading in the display of your multi-meter. The letter "K" is appearing. This "K" indicates that you must multiply the reading by 10^3 or move the decimal point 3 places to the right. The new coil secondary resistance is 8, 420 Ohms, which is within the spec that you quoted. The first two coils that you tested had secondary ohm readings in the 7, 000 range, which is out of spec from what you quoted. I hope this helps.


As a side note, the total resistance from the ignition source through the primary side should be about 3.0 Ohms. If you have a reading of 1.1 Ohms inside the coil, you should have a 1.9 Ohm ballast resistor, at least in 12V systems. I haven't looked into if the 3.0 Ohms is what is required for 6V systems. Good luck.

[stevemiddleton]

When measuring ohms resistance, the polarity isn't a factor.

[keithwarkentin]

Hi I just thought I would mention I have a 8N Ford tractor 1948 and it is 6V positive ground and it came with a resistor from the factory I wonder if a resistor would help the coil operate cooler I also had a 8N Ford I converted to 12 volt still positive found and I was going through plugs like crazy and was told I need a resistor so I had the original resistor wired in and had to wire in a second resistor. It may not apply but I felt like mentioning it good luck and God bless.

[frankdavidson]

test with an ohm ==waste of time all any coil is just 2 pieces of wire of small diameter and a certain lenght wrapt around a iron core primary winding is much smaller than secondary winding in turns ratio if you bought a new coil to replace the old coil swap it out if it helps good for if no help you spent money for nothing if you have spark tble start with condenser greater cause of weak spark also points pitting tells you condenser is failing or is wrong mfd value every coil has a certain value mfd condenser to match it for max spark --- also check dirty plugs causing miss always start tbl shooting with condencer part in system

[Kickinpony]

Find someone with a known good one, and test it (if they'll let you). Heck, test your 12V coil, see what it reads.

[smid]

That sounds high for the secondary; I would think more like 7.15k

[dalegribble]

Thanks, this is the first vid I've seen. My newly purchased classic car didn't start today. Ordered new points/condenser and coil. Needed them eventually anyway. I also just bought a multimeter and did this test just now. The primary went to 2 then to 0 and stayed there. Tried a few times. The secondary went to around 5 and stayed there. Shot coil? I'll do the same test on the new one and post back!

[dadcolo]

Yes, the auto ranging meter has only 3 places, and changes from a lower setting to a higher setting... #1 is 1.5 ohms, 7, 150. #2 is 1.5-2.0 ohms, 7, 790. #3 is 1.1 ohms, 8, 420. All are near the lower 8, 000 number, but should fire the plug. In 12 volt battery systems a 1.5 ohm coil requires a 1.5 ohm resistor to prevent over heating the coil from too much voltage. A 6 volt battery system requires a strong battery to supply enough voltage to the coil so it will fire on very cold starts because your cranking on the starter, and dropping the voltage below the coil's required voltage to fire, plugs get soaked with wet gas. Thanks for the video, I was wondering about those auto-ranging meters.

[frankdavidson]

only valid test of coil is connect it up see if it helps spark these ohms dont mean squat

[kbuxe]

are you running a 6V coil on 12V without a resistor ?
you should use about 2 ohm to 3 ohm resistor to feed a 12V into a 6V coil.
Running 12V into a 6V coil will absolutely make it over heat and fail.
Also some coils have an internal resistor. need to check..

[angusmacgyver]

the coil on my 77 plymouth measures 11.8 on the 20K setting, all 3 times.

[jamesfarley]

ohm readings are good but somewhat inconclusive as meters and users vary. probe tips don't work as well as alligator clips wiggled to bite in w spring tension. Overcharging systems impress more current thru primary causing overheating similar to key on points closed for extended periods.Secondary open circuit stress coil as voltage in secondary rises to a max until it can go to ground and cause insulation breakdown similar to a secondary terminal not plugged in good ie jumping a gap. In line resistors on 12 volt develop loose connections as well as hi resistance connecters. It gets involved but if the coil will jump a 1/4 in gap on normal crank u r probably ok on coil spark.

[scottt]

what year jeep do you have? my Ford 8n tractor uses this coil and I can't find a part number at auto parts stores

[linkgroundwalker]

looks like an Innova 3320 or similar multimeter, I have the 3320 and that would be 8.4K or 8400ohms as mentioned in other comments

[VWBeetle]

Was the multimeter auto ranging? If so then the 8.4 could have been scaled to 8.4K ohms.

[bush]

was the meter showing 8.4k which would be 8400ohms

[michelangelo]

i totally forgot how to do this but i think the starter went out on my chrysler conquest so here i am lol thanks man!

[russellellingworth]

What do i think. First coil positve red, black on negative. Second coil, you went positive red to negative and black wire to psitive terminal. HELLO