I installed NGK ZFR5N plugs and gapped them at 0.045" - this was 10, 15k miles ago? I take the plugs out now to do a compression test, and look at them, and tested the gap just for the heck of it. The 050 gauge fit in with room to play, the 060 didn't. The edges of the center electrode looked slightly rounded.

This isn't one or two plugs, they all appear to be worn evenly. They were used with an MSD 6A box then covnerted to ford EDIS (stock ford coil). Are these somehow harder on plugs then stock systems?

I'm assuming wear is directly related to how high the secondary voltage is. If secondary voltage only rises as high as it needs to jump the gap, I wouldn't think which ignition system you use determins plug wear. Of course I could be entirely wrong on my assumption, and its just time to change plugs.

Stock gap is 0.054" - if they were gapped smaller, leading to a smaller secondary voltage, wouldn't they wear less?

Yes, high output ignition systems will erode the plugs faster. Sparks like to jump off points and sharp edges so that's where the erosion starts and why the electrodes are rounded off.

I believe the rate of erosion has to do with current at the plug. I can ask Dr Jacobs to be sure.

Autolite plugs use a harder electrode that doesn't erode as fast as others. Platinum and iridium also don't erode very quickly. I would not buy Bosch platinum plugs though.

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Joshua

Mmm...not so fast! It was not Autolite versus "others" he was talking about, it was Autolite vs. Champion — the Autolite plugs of 15 or 20 years ago vs. the Champion plugs of 15 or 20 years ago when he put out that advertisement masquerading as a technical handbook. This old information out of "doctor" Jacobs' book, like most of the rest of the advice in that book, was questionable when it was first printed. It's even more dubious now — almost as dubious as the quality and reliability of most of his products. That said, if I couldn't have NGKs, I'd certainly have Autolites long before I'd have Champions (talking about today's plugs, not yesterday's).

You give good advice not to buy Bosch platinum spark plugs, though. They're just as bad as the rest of Bosch's plugs...worse, in some ways.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I've seen little change in Autolite or Champion spark plugs in the last 15 years. What, if anything, has changed in either brand?

Dr. Jacobs has a PhD in electrical engineering so the term "doctor" needs no quotations or otherwise needs to be set apart.

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Joshua

Yep! Higher secondary current = faster spark plug wear. Remember also that most distributorless systems are "wasted spark" systems, which fire the spark plug once when it counts (between compression and power stroke) and once when it doesn't (exhaust stroke). Many or most of these DIS use platinum or double-platinum spark plugs (platinum tip on the + and - electrodes) to deal with the extra stress placed on plugs by this kind of ignition system. I don't think you can get a double-platinum plug otherwise exactly precisely like the one you're running, but you can get very close: NGK will sell you a ZFR5LP-13G (stock number 7781: platinum fine-point centre electrode, 14mm, 3/4" reach, 5/8" hex, gasket seat, resistor, extended projected tip, extra long life, platinum tip laser welded on ground electrode, stock gap 0.050").

Autolite will sell you an APP985 with similar specs but no fine-point electrode. The advantage of a fine-point (or "fine wire") centre electrode is reduced arcover voltage requirement, which, again, is easier on the whole secondary side of the ignition system.

For reference, the ZFR5N you're running now has the following specs: 14mm thread, 3/4" reach, 5/8" hex, gasket seat, resistor, extended projected tip, v-grooved center electrode, stock gap 0.035".
That too, but since the voltage across the plug gap is a "pull" (system demand) rather than a "push" (system capacity), it's not likely that extremely high secondary voltage is to blame for your plug wear.
Mmmm...stock gap on which plugs in which system is 0.054"?
Yes, or you could change to a harder electrode material per above.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I'm kind of amazed you haven't seen much change especially in Champion spark plugs over the last fifteen years, given your usual attention to detail and the extreme decontenting (fancy word for "cheapening") job Federal-Mogul have been doing across all their parts lines. I have a front-row seat for what they've done to Wagner, and a second-row seat for what they've done to other lines like Champion, Anco, Fel-Pro, Sealed Power, and Moog. A few of the changes I've seen in Champion plugs over the last fifteen years include a technically unjustifiable degree of consolidation in the spark plug line, cheaper plating, less consistent side electrode placement, and sloppier threadcutting and side electrode welding. That's the front-of-house stuff that can be observed by holding a plug in your hand. The behind-the-scenes stuff (the processes by which Federal-Mogul produce the product) is considerably uglier — the usual problems one gets when the owners of an engineered-products company dismiss most of the company's engineers, replace them with MBAs who know little or nothing of how the product is supposed to be built and used, outsource components to countries not reputable for producing quality products, and focus on statistical quality control paperwork rather than actual quality.

As for Autolite, their plugs haven't been cheapened to the same degree as Champions, nor as systematically, but there've definitely been changes in materials and construction. That tends to happen over the course of two different, unrelated corporate parents in the last fifteen years (Allied-Signal and then Honeywell).
The way I see it, a degree does not necessarily earn respect. How the holder of that degree uses it determines whether he's worthy of respect or not, and having read "Dr" Jacobs' book and tried his products (not to mention his company's Clifford-like customer "service") over the years, and seen my bad experience duplicated multiple times with friends and family members, I have very little respect for him. His habit of trading on his title ("The Doctor's Guide to Optimizing Your Ignition [by sending me lots of money]") is the prime example. Perhaps if he weren't so busy shouting about how he's a PhD so we should all listen to him and buy his stuff, he'd have the time to do better work. The quotation marks stay. They're my text-based way of spitting on the ground when I speak his name. It's nothing personal; if Clifford or Mitchell went throwing titles around, I'd do the same thing with them.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

On spark plugs...

I have bought exactly one set of 4 Champion spark plugs in the last two decades and that was about a year and a half ago for the OHV 2.5 in my Dakota. 13-15 years ago I would routinely see broken Champion plugs delivered to the auto parts store where I worked. I've never considered Champions to have good plating and have found more seized Champion plugs than anything else. I figured the quality could not have gone down much since then.

Since my wages have not been earned in the automotive industry for some time I haven't been aware of most of the industry changes and how the products we rely upon have suffered.

On Jacob's Electronics and Dr. Chris Jacobs...

In 1999 Jacobs electronics was sold. It was subsequently sold again and is now part of The Mr Gasket Co. and has suffered much the same fate as the Federal-Mogul companies you describe.

His company produced some innovative products. I will concede that there were overstated claims and that holding the company to their claims was not always easy. Do you care to share any specific problems with Jacobs' Electronics products? Or should we maybe let it go?

Chris Jacobs himself is a very amiable and knowledgeable individual. I happened to meet him when I was working for Covad communications (slumming as a repair and install tech) and was sent to repair his DSL. We spoke a couple of weeks ago after I ran the slant 6 race in Medford. Chris told me of his bracket racing invention that was banned by the NHRA. It was essentially an accelerometer connected to a laptop and three lights. You set your dial-in on the laptop and the lights would indicate if you were on target to hit your dial-in or were going to slow or fast. The nitrous mastermind is thankfully still being made and will help keep my cast pistons safe.

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Joshua

Always a dangerous assumption where auto parts and beancounters mix! Every time I think Federal-Mogul have squeezed every last possible drop of blood out of a particular one of their operating branches, they manage to squeeze more. I'm beyond shock.
I can believe it, and certainly Accel have suffered considerably since being sold off from Echlin, but almost all of my sour experience with Jacobs' products and customer service came before 1999, so...?
And in the interest of fairness, I had one of his "variable magnetic core" coils on my car for a few years, and it worked fine. I doubt the fancy claims that were made for it, but it worked fine. OTOH, some of the nightmarish customer-disservice experiences I saw regarding their more expensive spark boxes and engine management systems made Sam Powell's experience with Accel look absolutely sublime by comparison. And many of Jacobs' products have been just plain fraudulent since well before 1999.
I'm sure he's both of those. I'm not sure why he ran his company the way he did.
That's pretty cool. And I do wonder if he ever got anywhere with his microwave ignition idea.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

True story:

I met a gal in 93 who had a 88 Chevy, 87k miles. First time I drove it, I told her it ran like crap, and asked the last time it had spark plugs and a tune up.

Her Answer:

"It doesnt have spark plugs, Its fuel injected"

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Unfortunatly for me I havn't been around long enough to notice all these changes you guys are talking about(only 18) but in personal experience I like using champs. I've got them in my 98 ram ss/t and they are alot better then the autolites I tried in there or the ngk's i bought it with. and I've been using them ever since without major problem I have gotten some that were shorting out and not working properly but I'd rather use those and have to replace one or two because they didn't work properly then using the autolites that caused the motor to run super rich.

One application is a 1994 Aerostar V6 4.0 - I believe any ford engine that used the similar coil (in 4 and 8 cyl variety) used the 0.054" gap.

Dan, both the NGK and Autolite plug you gave have the fine tip. Maybe the NGK one is a hair finer? hard to tell by pictures in online catalogues. Both are 3/4" reach, but the tip extends out further on the autolite judging by pictures. Hmm I have a set of ZFR5N's left but maybe I will leave those for the intrepid 3.5L in the driveway and try the ZFR5LP-13G in the slant.

Speaking of intrepid - NGK catalogues now show a FR5-1 - 22mm reach vs ~19mm reach of the ZFR5N. However the autolite still calls for 985. Interesting.

Spark plugs do not (cannot) cause an engine to run richer or leaner.

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Too many people who were born on third base actually believe they've hit a triple.

Oh, you're talking about the gap for that DIS, not for that spark plug. That's important — the range of adjustability in spark plug gap is not infinite. If you open or close a plug more than about 0.010" from its nominal/production gap, the side electrode will be at a significant angle relative to the centre electrode, which tends to localise the spark point and accelerate plug wear. The major makers all make some of their plugs in gap range variants.
From what I can see in the pics, the Autolite hasn't got a fine tip so much as it's got a necked-down (reduced diameter) tip. Shades of distinction; the NGK has a finer point.
I'll be curious to read your results.

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Too many people who were born on third base actually believe they've hit a triple.

i do use other spark plug brands, but have been installing autolites for 30+ years. when my parts houses started delivering me autolites MADE IN CHINA in big letters on the box it was time to switch to something else.( when the emt's arrived,they found me on the garage floor clutching a autolite box across my chest and mumbling something about made in china, made in china.... autolites made in china. ) i found out installing them. had 2 sets,one usa and one china. couldn't figure out why some plugs were green and some were black. poor quality, just look at the green top/tip autolites. last 2 threads MISSING at electrode ends , poor printing on plug in GREEN shaded ink , poor thread machining ,.002 LESS thread width,... etc. absolute junk. match up a china autolite to a usa plug before you still recomend them. ron

I'm sure this has been covered already, but i'll ask anyway.
I have a '79 Dodge b-100 /6, 1bbl. Holley. (1945)model. (I know, throw it away) What plug do you guys recommend for this application? I seldom tow anything, and it sees mostly highway driving. The engine is bone stock, never been apart, and has auto trans. Would the NGK plugs be worth the investment? I'm pretty sure I installed Autolite plugs at last tune up.
Opinions are greatly appreciated, Thank You.

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"MOPAR or NOCAR!"