Topic: Yellow Top Coil

[196667Bob]

Jeff : Thanks. I guess that I missed that. Are you talking about the part you quoted (change to Autolite), or the tower length ?

Thanks,

Bob

[196667Bob]

Jeff : My "friend Search" found it - right below the subject of the 8 Track tapes - duh.
My info of 1967 came from Mannel's book, which is obviously then incorrect. Good thing the "Posting Police" (you) are out there checking for offenders.

Does anyone ever contact Mannel, or any other publishers (like Kevin Marti) when things like this are found incorrect in printed publication ? Just curious if there is any "failsafe" for those no having the benefits of a "Policeman".

Bob

[J_Speegle]

Does anyone ever contact Mannel, or any other publishers (like Kevin Marti) when things like this are found incorrect in printed publication ? Just curious if there is any "failsafe" for those no having the benefits of a "Policeman".

Sure they do - but with the printed word what are they (the author or publisher) to do other than make a note and maybe make a correction in a follow up printing if that is ever done.

Same thing happens with magazine articles - once it's in print it's gospel for some and outdated sometimes within months or a year.

[196667Bob]

Jeff : I figured, and hoped that this was the case. I know that in the case of Mannel, he has issued a couple of "Addendums", most likely prompted by things just like this.

Just to make your other point clear ; am I correct then, that the general consensus is that all Factory (Assembly Line) coils from 1965-73, should have a number, a letter, or both between the two terminal posts ? Just want to make this clear for future questions.

Thanks,

Bob

[Bob Gaines]

Bob : I wouldn't go so far as to say that these markings are "missing" from the Repros. While Mannel also notes in his book that these are not "date codes", he also notes that the meaning of these markings is "unknown". As I noted previously, these "yellow top" coils were used from 1957 (January), through the 70's, and available as Service Parts for many years after. I have these "yellow top" coils for my 57 Retractable and T-Bird, my 59 Retractable and Ranchero, my 62 T-Bird, my 66 Mustang and T-Bird, and my 67 Mustang, as well as a few spares. The majority of the ones I have exhibit no markings between the posts. While, unfortunately, I can't say which, if any, are original assembly line coils, I would find it unusual if the majority were not. I say this due to the fact that it is fairly uncommon for a coil to really "go bad", and thus that so many of mine have no markings there - of course it is a possibility. Maybe the ones with the markings were "assembly line only", and the ones without were Service Parts ? Or possibly just from different suppliers for the Plants ? In any case, I think it is something that requires further investigation/documentation before saying that all yellow top coils should have the marking between the posts.

Actually, I am more interested in something else that occurred with these "yellow top" coils. When the first 12 volt coil was first used in 1956, it was Part # B6A-12029-B, and was black, with a black top. In January of 1957, the coil received the "yellow top". In early 1965, the indexing "bump" on the coil was eliminated. In 1967, the coil became stamped "Autolite". Then, and I don't know what year for sure, the "yellow top" was eliminated, and, at least the Service Part, became black again. The Service Part remained like this until it was "Not Replaced" sometime after 1990 (again, I don't know when since my last OSI catalog is 1990), but do know that it is no longer available 'due to low demand". Throughout all of these changes, the Part # remained B6A-12029-B. The "something else" that I am curious about occurred sometime during the "yellow top" era ; the tower of the coil (where the wire from the distributor plugs in), became longer. When did this occur, and why ? Possibly a supplier variation ? Once again, not enough of a variation to warrant Ford changing Part Numbers", or even a suffix. As I have come across some of these, I am interested in finding out the details.

Bob

It would be redundant for the markings to be a date code and also have a date code in the ink stamp placed on the coil. Besides compare a couple of different coil stamp date codes to the markings on the particular coil and they typically don't  match the stamp in any conventional sense. It is safe to conclude therefore that they are not date code markings cast into the coil . FYI the repros do not have those cast in markings. It is typical to find those cast in markings on 1965-1970 yellow top coils.

[196667Bob]

Bob : I have never thought, nor meant to imply that the markings were date codes. My point was, the majority of yellow top coils that I have, and have come across, do not have any markings between the terminal posts. That being said, according to Jeff's response, the ones that don't have markings are not from the 1965-73 models - at least from the Factory for those years.
On my other question, do you know when and why the towers were lengthened ?

Thanks for your input.

Bob

[CharlesTurner]

I suggest the codes on the top of the coil may simply be a mold/cast number.

[J_Speegle]

Bob : I have never thought, nor meant to imply that the markings were date codes. My point was, the majority of yellow top coils that I have, and have come across, do not have any markings between the terminal posts. That being said, according to Jeff's response, the ones that don't have markings are not from the 1965-73 models - at least from the Factory for those years.

That is what I've found and seen.

As for the markings there was a point where some thought they might be date codes, since we often grab that as a first possibility, though it did not hold up once enough data was collected.  Surely it helped with tracking batches of coils.

On my other question, do you know when and why the towers were lengthened ?

"towers"  are you asking about the terminals or the bases of the terminals? Just trying to get with the same terminology   

[Brian Conway]

Put the ' test ' to the coil currently on the 65.  Meter set at 200 ohms, red lead to BAT and the black lead to DIST.  Results are in: 2.0.   The secondary test yielded an inconclusive 1.0 ?  This coil has a raised mold or date stamp: 5D.  So correct in either case for my car ?  Brian

[midlife]

Many DVM's register 1.0 when resistance is higher than that setting can handle.  Re-set your meter to 2 megaohms or 200 kilo-ohms and try again.

[67gta289]

Or get an auto ranging model

[markb0729]

Brian, Remove the wires from at least one of the terminals on the coil and retake the measurement.  You could be measuring resistance somewhere else in the circuit.

[196667Bob]

+1 on midlife and 67gta289's Replies. To avoid any confusion for future readers of my "Test Procedure", I have modified my original Post to include setting the meter to the 200K scale when measuring Secondary Resistance. Of course if you have an "auto-ranging meter, this won't apply.

"towers"  are you asking about the terminals or the bases of the terminals? Just trying to get with the same terminology   

Jeff, what I refer to as "the tower", is the "snout" on the coil into which the "spark plug type" wire (typically referred to as the "Coil Wire")  from the Distributor is inserted.

In trying to find information on the Coil markings and the length of the "tower", I ran across some information that most likely was not enough to justify the addition of the "markings", much less a change in Part Number (the B6A-12029-B Part number was used until the Coil was finally "Not Replaced"), but nevertheless, interesting. The 12 Volt Ford Coils from 1956 through 1966, all show the Spec for Secondary Resistance as "8000-8800 ohms". The Spec for coils from 1967 through at least 1971 (the last Ford Shop Manual that I have when points were still used), shows Secondary Resistance of "7600-8800 ohms". Just an interesting "tidbit" of information.

Bob