Topic: Yellow Top Coil Specs

[markb0729]

I have an after market Yellow Top coil that was flaky.  The car would occasionally stumble at idle.  As a test, I replaced the coil with a non-concours BWD coil from the local parts store.  Low and behold the occasional stumble at idle disappeared.  I just purchased a new Scott Drake after market coil and the secondary resistance is out of spec just as with the first yellow top coil.  I think I'm going to contact Scott Drake or just return it.  The 65 Ford shop manual states that secondary coil resistance circuit should be between 8000 and 8800 ohms at 75 degrees.  Both yellow top coils have a secondary resistance reading of infinity.  The BWD coil is withing spec for secondary circuit resistance at 8800 ohms.  Primary resistance is within spec or close to it for all coils.  What gives here?  I've heard that the after market yellow top coils leave little to be desired as far as reliability is concerned.  Should I just paint the BWD coil so it looks concours correct (it's tallery than the yellow top coil) or are there other options?  Any sources for good after market concours correct coils?  I'm not looking to spend hundreds of dollars for a NOS yellow top coil.

[Bob Gaines]

I have an after market Yellow Top coil that was flaky.  The car would occasionally stumble at idle.  As a test, I replaced the coil with a non-concours BWD coil from the local parts store.  Low and behold the occasional stumble at idle disappeared.  I just purchased a new Scott Drake after market coil and the secondary resistance is out of spec just as with the first yellow top coil.  I think I'm going to contact Scott Drake or just return it.  The 65 Ford shop manual states that secondary coil resistance circuit should be between 8000 and 8800 ohms at 75 degrees.  Both yellow top coils have a secondary resistance reading of infinity.  The BWD coil is withing spec for secondary circuit resistance at 8800 ohms.  Primary resistance is within spec or close to it for all coils.  What gives here?  I've heard that the after market yellow top coils leave little to be desired as far as reliability is concerned.  Should I just paint the BWD coil so it looks concours correct (it's tallery than the yellow top coil) or are there other options? Any sources for good after market concours correct coils?  I'm not looking to spend hundreds of dollars for a NOS yellow top coil.

It is difficult at best if not a waste of time to try and disguise a modern after market coil to look factory IMO. The typical aftermarket coil is of a vintage GM coil design and is what it is regardless of what paint you put on it  (think lipstick on a pig) . The repro coils used to have a bad habit of failing when they got hot. I am not sure of the current batch. There are still so many original coils still available to salvage (used on millions of cars) that I typically restore a nice looking original. You can do body work on dents,recolor the yellow insulation and restamp them to suit the car if need be.

[sgl66]

There are still so many original coils still available to salvage (used on millions of cars) that I typically restore a nice looking original. You can do body work on dents,recolor the yellow insulation and restamp them to suit the car if need be.

This is the way to go, just make sure that it isn't shorted or open. I picked up one for $20 on eBay a few years ago

[markb0729]

"Lipstick on a pig". One of my favorite lines.   . Just looked on eBay, slim pickings and most are pretty beat up on top.  I'll try Craigslist.  What do you think is a reasonable price for a coil with a decent top?  Of course I'll repair and repaint the bottom if need be.

[Bob Gaines]

"Lipstick on a pig". One of my favorite lines.   . Just looked on eBay, slim pickings and most are pretty beat up on top.  I'll try Craigslist.  What do you think is a reasonable price for a coil with a decent top?  Of course I'll repair and repaint the bottom if need be.

20-40 on the high side needing to be restored . The problem is getting a seller to test one .

[rrenz]

http://www.virginiaclassicmustang.com/YELLOW-TOP-IGNITION-COIL-P1184.aspx


I Installed this one on my car just about two years ago. They had just introduced this on their site at the time I was finishing up a refresh on my 289. Was going around in circles trying to find a decent looking and performing coil. Picked this one up from Virginia Mustang and Haven't had any issues with it.

[markb0729]

http://www.virginiaclassicmustang.com/YELLOW-TOP-IGNITION-COIL-P1184.aspx


I Installed this one on my car just about two years ago. They had just introduced this on their site at the time I was finishing up a refresh on my 289. Was going around in circles trying to find a decent looking and performing coil. Picked this one up from Virginia Mustang and Haven't had any issues with it.

Did you happen to measure the primary and secondary resistance of the coil?

[rrenz]

I haven't no..

[NEFaurora]

I agree with Bob.. I usually never pay more than $40-$45 for an Original 60's Ford one...

Get an Original coil..  The aftermarket ones are crap.  They WILL Fail....

As far as really good reliable aftermarket coils are concerned, I'd highly recommend the Pertronix "Flamethrower" coil, or any coils made by "Standard Motor Parts".
I'd stay away from today's Borg Warner...(BWD) They've gone really downhill the last 18 years...and are now crap as well as any Brand "X" ones...

)

Tony K.

[markb0729]

Thanks Tony.  Good to know the info about the Pertronix coil.  I'll also keep my eyes pealed for a good reasonably priced original yellow top coil.  The ones I've seen have been in pretty rough shape and the seller thinks they are sitting on a pot of gold!   

[Texas Swede]

Well, I used a repo yellow top in my car in Sweden and it failed. Used a Holley coil and it
failed. Then bought a Pertronix and guess what, it failed. Had several originals and put
one into the car and it has now worked for many years (summers).
Texas Swede

[67gtasanjose]

I'd stay away from today's Borg Warner...(BWD) They've gone really downhill the last 18 years...and are now crap as well as any Brand "X" ones...

I couldn't agree more about BWD coils. I installed 8 of them at one time on a particular "Brand X vehicle" with coil-per-plug set-up. (replaced because of a floating random mis-fire and the original coils were splitting from rust-intrusion).  Miss-firing went away. About 8 months later, I had a failure of just one,...then two more about a month after that, then last week I changed yet another two...each time, it's a different cylinder. (Thank GOD for scan-tools w/data monitoring!)...3-more to go and I guess we start all over again! Parts store has been warranty-ing them but what is my time and my customers aggravation worth??? About to switch over to OEM coils (in this case, G.M.)

[jwc66k]

Many years back, a friend had a reproduction yellow top coil failure (67 289 "C" code) and an analysis at a dealership (our Mustang club's sponsor) indicated it was wired internally incorrect. This has been a problem for a long time. The best coils are used if you can find one in good condition.
Jim