440IC can't get spark

[jdman]

"The damn thing had terminals that were crap. One of them started spinning when I tightened it"


That Coil Is NO GOOD NOW......... Theres A Small Wire On The Back Side Of That Stud, And If It "Spun" Then That Wire Broke And The Coil Is Shot.....

Jeff

[jdemaris]

I read somewhere that many 12 volt vehicles use 6 volt coils. Hence the external resistor to take it down to 6 volts. I can try my other coil though.

If the farm stores had 6 volt coils in stock I'd trade in my spinning term for another. I should return it anyway.

If I go 12 volt pertronix with a flame thrower coil maybe my spark issues will just go away anyway.

Technically, there IS no such thing as a standard "6 volt coil" or "12 volt" coil. It is more complicated than that.

Each system is designed to handle a certain amount of max. voltage, along with a certain amount available at cranking.

A 12 volt system usually only has around 9 or 10 volts when the engine is cranking. So, a 12 volt system needs a coil that can make ample spark at 9 volts, not 12. 12 volt starters are designed for 9 volts, not 12.

A 6 volt system only cranks at around 4 to 4 1/2 volts. So, the coil must be able to make good spark at 4 volts.

A tractor or auto company can use any combination of things they want. When you buy a generic coil, they are "generalized" and often put into a few classes. Often a 6 volt coils is deemed fine for most 6 volt system with no resistor, or the same for most 12 volt systems WITH a resistor. But, like I said, that's greatly simplifiying things. Coils are made of windings, and those windings can amount to almost anything.

Deere, for one, made certain engines that start terrible with generic coils. 1010 gas engine is famous for that. A generic 12 volt coil put onto a 1010 usually winds up with an engine that will not start cold. When 1010s were new, there were three different part # coils used, depending if a Wico, Delco, or Presolite system.

In regard to your two-cylinder Deere? At the least, it ought to have a high-amperage 6 volt coil. The coils that Deere sells are cheap. Made in China, yes, but they work fine. To my knowledge, Deere never published the test or resistance specs on those coils. Same coil that the 440 uses is also used in the 1010.

As to going electronic? They work fine until a part fails, and you can't run downtown to buy something to fix it. Also, these electronic conversion companies come and go. All the companies I bought in the 1960s are now, long gone. I suspect the same will happen with those selling kits now. Breaker point ignition works fine, and . . . if a system dies you can always find a way to make it work. Just requires a little maintenance.

[Ray III]

#1 your coil appears to be a 12 volt coil, not a 6 volt coil. Please confirm or tell me I'm wrong. I don't recall ever seeing a 6 volt coil with "external resistor" warnings.

The warning reads "use with external resistor" which means it is a 6 volt coil and if used in a typical 12 volt system must have a resistor in series to cut the voltage to what the coil is designed for. Otherwise the coil would eventually burn out at 12 volts.

If the thing was made in China I would throw it right over the bank and get a NAPA Echlin coil.

[snoopy]

been following this story and have gotten confused and lost several times. I will only add that when you put the dust cover on make sure that it is indexed correctly. it should only fit correctly in one position.

[jdemaris]

The warning reads "use with external resistor" which means it is a 6 volt coil and if used in a typical 12 volt system must have a resistor in series to cut the voltage to what the coil is designed for. Otherwise the coil would eventually burn out at 12 volts.

If the thing was made in China I would throw it right over the bank and get a NAPA Echlin coil.

There isn't really any such thing as a "6 volt" or "12 volt" coil. It is a system created by parts sales companies to reduce inventory.

A coil, regardless of system and cranking voltage, can be just about anything. All depends on who designed the system and how.

As far as China goes, some stuff is fine and some not. Just about anything you buy now, comes from China or some other cheap-stuff nation, regardless of brand name.
Last I heard, DANA bought Echlin and has factories all over the world, including China, Brasil, Dominican Republic, and Mexico.

[Lavoy]

This might clarify things, might not.
6 volt and 12 volt externally resisted coils are the same, and will read 1.5 Ohms across the terminals.
A 12 volt internally resisted coil will read 3 Ohms across the terminals.
On a 12 volt system, you need to have 3 Ohms of resistance to keep the points from burning, the question is how you acheive it. Either use an internally resisted coil, or an externally resisted coil in conjunction with a ballast resistor.
Lavoy

[Ray III]

The warning reads "use with external resistor" which means it is a 6 volt coil and if used in a typical 12 volt system must have a resistor in series to cut the voltage to what the coil is designed for. Otherwise the coil would eventually burn out at 12 volts.

If the thing was made in China I would throw it right over the bank and get a NAPA Echlin coil.

There isn't really any such thing as a "6 volt" or "12 volt" coil. It is a system created by parts sales companies to reduce inventory.

A coil, regardless of system and cranking voltage, can be just about anything. All depends on who designed the system and how.

As far as China goes, some stuff is fine and some not. Just about anything you buy now, comes from China or some other cheap-stuff nation, regardless of brand name.
Last I heard, DANA bought Echlin and has factories all over the world, including China, Brasil, Dominican Republic, and Mexico.

Just explaining why you see the warning.

You can avoid China stuff if you really care to. Usually means buying your stuff from places that specialize in the product. I have a place that I can buy American made bearings, one that I can buy American made electrical supplies, etc. As for Echlin coils, they were still made in USA last I saw.

[Ray III]

Well, reason I am following this one is the ignition quit on my 420 too. Turns out it was the 50 year old wires were broken internally. I could get 6 volts at the coil and get it to drop to 0 by poking the wire bundle. Even when it was showing 6 volts it would drop to almost nothing when the starter was engaged. Replaced the wire from fuse to switch and switch to coil and it has never run so good.

So is there any way that you are moving the wires in the act of installing and removing the distributor cap? I don't remember if you already replaced the ignition wire, but keep in mind there are also wires to the switch that can go bad. Make sure you have 6 volts at all points in the circuit no matter how much you shake the wires.

[jdemaris]

This might clarify things, might not.
6 volt and 12 volt externally resisted coils are the same, and will read 1.5 Ohms across the terminals.
A 12 volt internally resisted coil will read 3 Ohms across the terminals.
On a 12 volt system, you need to have 3 Ohms of resistance to keep the points from burning, the question is how you acheive it. Either use an internally resisted coil, or an externally resisted coil in conjunction with a ballast resistor.
Lavoy

That works fine as a generic explantion, but it's not true in OEM reality. There are shades of variations that you could fill pages with. Even with the Deere 1010, when new, there were three different coils, and every one of them gave a different ohm reading across the primaries, and secondaries.
That's one reason why 1010s with Presolite ignitions burnt up points much faster than those with Delcos.

For the generic aftermarket world, that general explanation for 6 volt and 12 volt coils works fine. Otherwise, it does not and there really is no such thing as a standard 6 volt or 12 volt coil. It all depends on the overall design of the system.

[Lavoy]

The explanation I posted comes from a man with 30 or more years of ignition and electrical experience who derives his sole living from the selling of electrical parts for antique tractors and vehicles. He is also probably the largest antique tractor wiring harness manufacturer in the US. From the way he explained it to me, that covers most standard ignition coils used on tractors and older vehicles, not just a few aftermarket ones.
Lavoy

[jdemaris]

The explanation I posted comes from a man with 30 or more years of ignition and electrical experience who derives his sole living from the selling of electrical parts for antique tractors and vehicles.

No offense or insult intended here, but his 30 years don't prove, nor do they disprove a thing - any more then my 40 years experience does or does not. Things are whatever they are - and different people, with varying backgrounds can have different opinions. The hard facts stay the same regardless of who says what.

Many older coils used in 6 volt systems can vary, on the test bench, from at least 4 to 8 amps on the primaries at 4.5 volts DC. 4.5 volts is the standard test voltage since that's what most 6 volt system coils get when an engine is cranking.
Use Ohm's Law V=IXR and that gives a resistance, in ohms, from 1.5 ohms down to only 1/2 an ohm.

Many coils used in 12 volt systems bench tested at 9 volts can vary from 4 amps to 1 amp. That gives resistances of 4 ohms down to 9/10 of an ohm.

Thus the reason why grabbing old, unidentified coils and trying to ID them simply by primary resistance readings can be misleading. Especially true with some 20s-40s vintage coils that are polarity sensitve, and/or were used with polarity-changing ignition systems. Some such systems alternated between positve ground to negative ground in an effort to preserve points life.

There never has been a generic standard 6 volt or 12 volt coil. For fairly modern engines built in the 50s to 70s, the generic labelling system works OK for most part - but still, technically, is NOT accurate. Some engines are particularly prone to not starting well with generically suggested coils.

[boler76]

To the original question, did you ever come up with an answer to the no spark situation or did it lose its significance in the resistance theories Just wondering what the problem really was

[joeturner1977]

Tim_in_IA

Did you slove the "no spark" problem???

[JD440ICD2006]

Along with spark, he may have lost his Internet connection. Problem is, there is no one around that has "30 years experience" with the Internet since it has not been around that long as we know it today.

[Tim_in_IA]

I never did solve it. i am going to order the pertronix and do all new 12 volt this spring. i need new gauges anyway. I'll just replace everything and hope for the best.