Tar on top of coil question

[Jim11787]

New to model T’s and have noticed some tar spots on top of 2 coils in my T. Is this something I should be concerned about?

[TXGOAT2]

Maybe.

It could indicate that the coils are overheating due to poor adjustment, sticking points, or being allowed to buzz for extended periods of time. A shorted capacitor might also cause overheating. (?) A few other, less likely conditions could cause overheating.

If your engine runs really well and your coil points and timer don't give trouble, the coils are probably OK.

Coils work best when run on the magneto.

[Jim11787]

Thanks. My magneto isn’t working. I run on 12 volts. Will get my coils serviced so I know they are good to go.

[Moxie26]

Jim ... Locally, is there someone in your Long Island chapter that could help you with your coils ? .... Overheated coil tar usually expands out the top opening of the primary coil under the vibrator. The glossy tar like smudges on top coil wood seem to be applied, not originating from internal Hot tar. Whoever you send, will check secondary coil electrical integrity around 3,200 ohms making that unit eligible for rebuilding...... Your magneto can be recharged to provide power to your ignition system as Ford intended separate from the battery powered source.

[Jim11787]

Jim ... Locally, is there someone in your Long Island chapter that could help you with your coils ? .... Overheated coil tar usually expands out the top opening of the primary coil under the vibrator. The glossy tar like smudges on top coil wood seem to be applied, not originating from internal Hot tar. Whoever you send, will check secondary coil electrical integrity around 3,200 ohms making that unit eligible for rebuilding...... Your magneto can be recharged to provide power to your ignition system as Ford intended separate from the battery powered source.

Thanks Robert. I agree in looking at them it does not seem to be coming out of the coil box. I did run them on a friends ECCT tester today. Caps were good but other tests were poor or good. I have ordered an etimer so I don’t think the coils will need rebuilding as long as the windings are working. In the meantime I developed a carburetor issue with leaking fuel. Float bubbled in the hot water test. Will be installing a new float and needle valve and seat. My friend lent me 4 good coils to get it running in the meantime. Once I get it running again I will install the etimer and try my coils with the resistor shunts installed and see how it runs.

[Moxie26]

Good decisions.... Keep us posted on your progress.... You may even revert back to a trusty six volt battery power system that Ford installed at the factory.

[Jim11787]

Good decisions.... Keep us posted on your progress.... You may even revert back to a trusty six volt battery power system that Ford installed at the factory.

Maybe one day. But would need to fix my mag first and I’m not up to that right now.

[TXGOAT2]

Your magneto may have an issue with the mag post terminal contact or the wire leading to the ignition switch, or with the switch itself. Those problems can often be corrected without major work or expense.

[Moxie26]

Jim..... Txgoat has a good suggestion to check those items, especially with an analog continuance meter, to later trace the path of AC magneto voltage from the magneto straight through to the ignition switch, coils, and spark plugs..,.... Using a 12 volt battery often has destructive effects on both your starter bendix when it mates with the flywheel ring gear during starting.

[Jim11787]

Jim..... Txgoat has a good suggestion to check those items, especially with an analog continuance meter, to later trace the path of AC magneto voltage from the magneto straight through to the ignition switch, coils, and spark plugs..,.... Using a 12 volt battery often has destructive effects on both your starter bendix when it mates with the flywheel ring gear during starting.

Thanks. Will follow suggestions. I have a 12 volt starter to avoid the mentioned problems.
To check the mag post can I just see if I measure any voltage to ground with the car running?

[Jim11787]

Your magneto may have an issue with the mag post terminal contact or the wire leading to the ignition switch, or with the switch itself. Those problems can often be corrected without major work or expense.

Thank you for the suggestions. I will check this out.
Jim

[Moxie26]

>>>>To check the mag post can I just see if I measure any voltage to ground with the car running?<<<<<<<<,,,,,........ Remove mag post, check continuity with analog meter from the screw terminal to internal spring post that connects with the magneto frame solder terminal.... do the same continuity with the detatched magneto wire and coil box terminal, with the ignition switch in the "Mag" position .... Using the meter on the magneto contact and ground will show to be ok since it is the way the first mag coil is connected to the following 15 coils ending being grounded to the magneto coil ring assembly, all done with the engine off....... After starting engine, use the analog meter to register the AC voltage... above idle, AC voltage should be about 10 VAC, going up to 25-30 VAC at speed............Attached photo gives procedure to re-charge magneto..........................................................I find it easier to check magneto AC voltage using the analog meter probes touching the red magneto terminal on firewall junction block and frame ground, instead of facing engine heat and noise under the dash.

[Jim11787]

Thanks Guys!

[Mark Nunn]

Jim, if you decide to do an in-car magneto re-magnetizing, the drawing that Robert posted is very helpful. But search the forum posts for the specific procedure to ensure success. Just connecting wires as shown will not work. Also, that drawing is old and deceiving. The centerline of the compass should be 1 ¾” to the left of the post, not the edge of the compass.

I’m hoping that you discover a simpler reason for a non-functioning magneto. I went through the same problem in my Runabout. I eventually used a borescope to see that my magneto ring has no coils on it. In fact, the top of my magneto ring is missing! Good luck.

[Moxie26]

Mark;.. check the picture for dimensions again please.... . The pointer of the compass is positioned over the south magnet pole when the magnet pole is in the center of the oval coil winding on the magneto frame..., All in reference to the position of the magneto terminal that Ford installed. ... ... Three 12 volt batteries can be connected instead of six 6 volt batteries using 2/0 size short battery jumpers, along with corresponding size jumper cable to the magneto post while flashing to the frame with the negative.

[Mark Nunn]

I understand the concept, Robert. I don't have first-hand experience with this process. I only know what I've read on this forum. My comment about the 1 3/4" dimension was also mentioned by others in the past. If I have a 3/4" diameter compass and you have a 2" diameter compass, our pointer positions will differ by 5/8". Which is right? I don't know, maybe neither. I must defer to others who have done the procedure. I apologize if my comments have added unnecessary confusion.

[speedytinc]

Look for the Tom Carnege method & forget all that compass BS.

[Mark Nunn]

Look for the Tom Carnege method & forget all that compass BS.

Found it. Thanks for the nudge, John.

https://www.mtfca.com/discus/messages/5 ... 28397.html

[speedytinc]

You're welcome.
Tom's method works real easy. Makes for a super hot magnet charge.

[Moxie26]

Ron Patterson's response from the Carnegie magneto charging posting ..... "The purpose of the "compass thing" is to ensure you are recharging the magnets in the same magnetic orientation as they were originally charged.
Certainly the in car recharge will work, but recharging the magnets in the opposite direction from original with a less than optimum ampere turn source/distance is not a wise thing to do.
Ron the Coilman "

[speedytinc]

Ron Patterson's response from the Carnegie magneto charging posting ..... "The purpose of the "compass thing" is to ensure you are recharging the magnets in the same magnetic orientation as they were originally charged.
Certainly the in car recharge will work, but recharging the magnets in the opposite direction from original with a less than optimum ampere turn source/distance is not a wise thing to do.
Ron the Coilman "

Read the WHOLE link.
Tom explains why it doesnt matter & did exhaustive testing for all the nay sayers comments.

I have re-charged magnets in car using both methods.
IMO The compass method is obsolete. Akin to using a buzz box VS an ECCT to adjust coils.

There will always be a small % of deniers, no matter how much proof is offered.

[Moxie26]

John Carvaly ..... I read the entire posting by Carnegie, and I am not denying his view. If you did not care for my posting, you also DENY Ron Patterson's intellegent procedure for magnet recharging. Period .



"The purpose of the "compass thing" is to ensure you are recharging the magnets in the same magnetic orientation as they were originally charged.
Certainly the in car recharge will work, but recharging the magnets in the opposite direction from original with a less than optimum ampere turn source/distance is not a wise thing to do.
Ron the Coilman "

[Scott_Conger]

So there, John!

There is no point debating someone once they appeal to authority...you position becomes null and void and theirs is unassailable.

Now, it's true that there is a truly "correct" way to do this, and kudos for Bob's pureness of heart, but there is also a way that doesn't leave you on the side of the road looking for a compass, also. As a retired engineer, I'm a big fan of "the right way", but will tell you that some of my biggest successes were behind closed doors and I was given the time to "get it done". When people asked me how on earth I accomplished this thing or that thing, my usual response was "I did it because you guys weren't around telling me it wouldn't work and constantly getting in my way in the process".

Given Carnegie's excellent showing at the MT500 year after year, one must wonder just how many MT 500's top places or outright wins were in a car that was charged "wrong"?

Now, giving credit where credit is due, it takes some massive clackers to point out the fact that probably one of the best Model T mechanics in the US or possibly the world, known for wringing the last ounce and iota of performance from a Model T, doesn't know what he is doing and worse, giving spurious advice to the ignorant masses. So, there is that...