Autolite Double Platinum Spark Plugs?

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My 1991 MX6, 2.2l, needs new plugs. I have 115,000 miles on a set of Bosch Platinum +4's and they're finally starting to misfire. I bought the +4's because they had the highest platinum content at the time (everyone knows that they don't create 4 sparks, but the open design might help flame propagation and offers 4 grounds to wear down rather than 1). I've been very happy with these plugs and their service life.

2 of my plugs are seized and I may need a heli-coil repair after removing them. So I'd like to put another very long life plug in to avoid dealing with them again. The options are:
-NGK Iridium (very popular and $)
-NGK Laser Platinum (apparently the best NGK plug for my application, but $$$)
-Autolite Double Platinum (allegedly long lasting and quite affordable)
-Bosch Platinum or Fusion +4 (I've had great experience with these and they're medium priced)

Iridium seems to be the flavor of the week in spark plugs and everyone loves the NGK Iridium IX. But interestingly they are rated as having a shorter service life than the "Laser" Platinum. I'm guessing this is because the "Laser" series of NGK has Platinum on the ground (side) electrode, as well as Platinum (or Iridium) on the ground electrode. NGK says these expensive Iridiums are good for 40k to 50k miles, while the Laser Platinums are ok for 80--100k: http://www.ngksparkplugs.com/pdf/DYK_LaserIridium_vs_Iridium IX.pdf

The double precious metal plugs are designed for Distributorless Ignitions, which in some designs fire in reverse on half of the cylinders. So the spark jumps from the side (normally the ground) electrode to the center electrode, rather than the conventional center to side. These systems NEED double platinum, or a normal side electrode would wear prematurely. You can read about it here: http://am.delphi.com/news-spotlight/tech-tips/ignition-electronic/

Which brings me to a very inexpensive set of Autolite Double Platinum plugs, similar to NGK's "Laser" series (with double precious metals on both electrodes). Autolite claims they're good for 100k miles, which easily should outlast my car.

Before everyone chimes in with "I use brand X, and it's just super" I really don't care about branding or what type of plug worked well for the last 30 years, or which one people had trouble with in a car 10 years ago. These are very different from conventional spark plugs and likely aren't made by Autolite anyway. I'm really not a fan of Honeywell/Allied Signal products (certainly not their orange oil filters, or their jet engines, all are [censored] IMO) but these plugs might be a good purchase.

Anyone have any experience with Autolite Double Platinums?
 
the autlite double plats are good plugs. There's no guts or glory with them. they work, they fire, they last 60k or therabouts.

Honestly for your Mazda, I'd put NGK V-Power plugs in it.
Reason.. that was the factory plug.

Putting an exotic plug (+4, iridium, laser plat) is more of a waste of money for your motor. You're buying longevity.
the V-Power would be good for at least 35k. It's a 4cyl motor, easy to swap plugs on.. total time would be 15min. (after you get the stripped threads taken care of).
I think you'll be fine with the V-Powers.

If you want to change things up just becasue, the autolites will be fine. There'll be no issues with them. Just make sure you set the gap & put a dab of anti-seize on the threads.

as for the +4, well while there's 4 prongs to wear down, the problem with them is its tendancy to misfire due to the spark not knowing which prong to fire on at that given moment.
As current flow to the path of least resistance, if 2 prongs are just right there resistance wise, and the other 2 prongs are to high, the spark might try to split and if it's able to, it won't be the full spark, so you get a weak spark and you misfire.
They're a great hype plug however...
 
The Autolite APPs are a fine spark plug but considering you expect you may be using a helicoil, go with the Laser Platinum. The APPs will sometimes (not very often) drop a puck and if that happens you'll be taking it back out again.
 
I too used Bosch +4's in the past. I would go with the Iridiums, the set I replaced in my daughter's Malibu with 110,000 miles on it, looked brand new! They also use them in the newer Corvettes. They are great plugs, the best nowadays. I put them in my Murano.
 
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Thanks for the responses. V-power just don't last, and for the difference in price I'd gladly go "exotic" just to save having to do the job again. It's about a $15 or $20 difference in price. The better metals also stay cleaner and are less susceptible to fowling.

The car didn't come with NGK's from the factory anyway. And the myth that NGK is for Japanese cars, and AC Delco is for American cars, Bosch for the Germans is total bunk. I've had excellent results with Bosch's in Chrysler and GM V8's and V6's. Anyway, my "Japanese" Mazda was built in the USA.

I don't subscribe to the theory that whatever plug came out of the factory 22 years ago is the best one for the engine. Heat range and gap are not something you generally mess around with unless you have some modifications, but I don't buy the concept that a particular brand is the better one for a car based on which continent it's put together on. I think the better plug for any engine is the better plug, regardless of who's label is painted on it.

I've never heard of or had any misfire issues with the +4, until I hit about 110,000 miles. The path of least resistance is the path the spark takes. That may switch between ground electrodes over time as one wears or gets dirty, but the spark doesn't get confused - it just jumps to whatever ground is the best one. There is some marketing hype in the +4's, but they do have a higher platinum content than other platinum plugs and allow the flame kernel to grow nicely. Bosch never claimed that they made 4 sparks, unlike the snake-oil grade Splitfire plugs.
 
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Im using app65s on my dodge aries...double platinum. I haven't noticed any "drivability" change...but the previous RC12yC plugs were definitely due...lol. Not much left of the elctrodes
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I wish I snapped pics....but yea, I dont notice any "seat of the pants" increase with the APPs though....I know over at allpar (Chrysler Dodge enthusiasts site) they shy away from platinums in these older 2.2L engines...and say to stick with the factory RC12yc....but so far, so good, we'll see if they last like these ~60k RC12yc's lasted
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Both of the NGKs are iridiums. They do not make Laser Platinums. The Laser Iridiums have an iridium center electrode and platinum ground whereas the Iridium IX are lacking the platinum on the ground electrode, which is probably the difference in longevity. I would go with the Laser Iridiums.
 
Originally Posted By: NMBurb02
Both of the NGKs are iridiums. They do not make Laser Platinums. The Laser Iridiums have an iridium center electrode and platinum ground whereas the Iridium IX are lacking the platinum on the ground electrode, which is probably the difference in longevity. I would go with the Laser Iridiums.


NGK makes two lines of plugs named 'Laser' (laser welded): Laser Platinum (double platinum); and Laser Iridium (iridium center electrode, platinum pad on side electrode).

In the case of the OP's Mazda, the Laser plug NGK recommends is platinum, not iridium.

Why not just put in a new set of the same Bosch plugs you used previously? It seems they worked well for you.

Quote:
I don't subscribe to the theory that whatever plug came out of the factory 22 years ago is the best one for the engine. Heat range and gap are not something you generally mess around with unless you have some modifications, but I don't buy the concept that a particular brand is the better one for a car based on which continent it's put together on. I think the better plug for any engine is the better plug, regardless of who's label is painted on it.


Conventional wisdom was to use ACDelco plugs in GM products, Champion plugs in Chryslers and Autolite plugs in Fords. The basis for this flawed logic is that NGK or Denso worked closely with the Japanese brands in plug development, Bosch with the Germans and the American plug brands with their respective auto makes.

It may be flawed, but it is valuable advice to consider. Example: NGK makes many different plugs for older Japanese cars, a special plug tailored for each car model if you will. Autolite just carpet bombs the market. Autolite generally just recommends Plug #65 in copper (along with whatever plug numbers are #65's equivalent in platinum or iridium) for nearly all of them, with highly variable results (#65 may be just okay in one model of car while it is terrible in another).
 
OP: I looked up your Mazda on Autolite's website, it looks like your MX-6 takes their 5224 series plugs. In their cross reference they claim it replaces nineteen, yes that's right, 19 different NGK plugs across 4 different NGK heat ranges! Precisely why I avoid Autolite.

At least they're not as bad as Splitfire, though. Splitfire would have used 1 plug number to replace 59 different NGK plugs across 6 heat ranges.
 
I have used Bosch IR Fusion and seems to be doing well for my Taurus, but like all other applications you should check online to see if there are a lot of people having problem for your application before you buy and use it. What works for one car may not for you. This is true for all non OEM plugs.

I personally had Autolite Copper and it didn't work well in my Corolla, NGK and Champion both work fine for me. If you don't want to take a chance, can afford to pay for OEM, or don't have time to mess with it, just stick with the OEM.
 
Autolite makes a fine spark plug. Use them with confidence. Look out for rebates too as they run often.
 
About 10 years ago my sister had a 91 Probe 2.2L, basically the same as your MX6. Of all the 4cyl economy cars that have been in the family, that Probe/MX6 is probably my favorite. Excellent car.

Anyway, like you, her plugs were missing and turned out to be seized. From memory the vehicle's mileage was around 100k and by the plugs' condition it was suspected they might have been in that long, but no way to be sure as she had bought it used.

Honestly I think it's a better strategy to replace them more often rather than less, so they won't seize.

I do subscribe to the belief of using the factory spec plug, or at minimum the same type under a different brand, as I believe the ECM is tuned for it. But it's not something I'm real dogmatic about, if other plugs work for you then great. Some cars might be more flexible than others.

Anyway, my suggestion is that if you don't want to use the spec plug (whatever it is), then use the same plugs you used last time as they apparently worked well. Instead of trying to extend their replacement interval, plan on shortening it and don't forget the anti-seize. As far as I remember they're easy to get to on that car.
But I guess you could look at this as a case where if you ever need new plugs again, you'll be ready to put a new head on it. If that's how you're looking at it then fair enough.
 
I went with Bosch Iridiums. They were $6.99 at Advance, which was a real bargain and much less than the comparable NGKs. The Bosch Iridiums have a fine wire iridium center electrode, AND a platinum and iridium alloy ground electrode. Both are laser welded in place, which, according to Bosch's marketing hype is better than the competitor's methods of welding the precious metals into the electrodes.

I've had great success with Bosch spark plugs in many engines, and these made in Germany plugs look and feel to be excellent quality. My last set of Bosch +4's lasted nearly 120,000 miles. I passed an emissions test last summer with flying colors - virtually new car levels of emissions with 370,000 km's on the engine. The plugs were apparently still firing well with about 110,000 miles on them.

I was leaning towards NGK IX's. But, NGK Iridium IX's do not have a precious metal ground, only the center electrode is iridium and their advertised life span isn't that long. To get both the center and ground electrodes in special super metal, you need to get NGK "Laser" series plugs which I could not find at any stores near me and are very pricey.

The Bosch's are pre-gapped which is great, since gapping precious metal plugs can easily damage the electrodes if you're not careful.

Like any new spark plug (regardless of the quality) the car now runs much better. You could use coat hangars to make spark plugs and the car would initially run much better than worn out plugs. But these Bosch's will continue to provide consistently good performance well beyond the life of the car. Bosch Iridiums, highly recommended. http://www.boschautoparts.com/SparkPlugs/Pages/Iridium.aspx#overview
 
I use Autolite Double Platinums in every single one of my cars - I've been very happy with them and they've proving very durable.
 
I went with Bosch Iridiums. They were roughly half the price of the NGK's and very close to the Autolite DPs. But, in addition to iridium center electrodes, they also have an iridium/platinum piece in the ground electrode similar to the Autolite double platinum and expensive NGK Laser series. The Bosch's are also "360 degree laser welded," apparently better than the pulse welding used by "competitors." They also came pre-gapped, which is good since it's easy to damage iridium plugs when gapping and saves me the trouble. I'm pretty happy with them, from appearances they look like a quality product with very nicely machined metal parts and precise electrodes. The misfiring is gone, car runs great. Thanks for all the advice.

From Bosch's website: http://www.boschautoparts.com/SparkPlugs/Pages/Iridium.aspx

and:
http://www.youtube.com/watch?feature=player_embedded&v=m-oLGUE3hFE
 
Originally Posted By: Gannet167
I was leaning towards NGK IX's. But, NGK Iridium IX's do not have a precious metal ground, only the center electrode is iridium and their advertised life span isn't that long. To get both the center and ground electrodes in special super metal, you need to get NGK "Laser" series plugs which I could not find at any stores near me and are very pricey.

The Bosch's are pre-gapped which is great, since gapping precious metal plugs can easily damage the electrodes if you're not careful.


Iridium IX is very fine wire, 0.6mm diameter, so it only make sense that they are trading durability for lower firing voltage.

Unless your car has waste spark (which yours is not as it has distributor cap and rotor), your side / ground electrode will last way longer than the center electrode regardless of material.

Most NGK for Japanese cars come pregapped.
 
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I am still enjoying drivability of my 2005 ford focus with new Autolite AP104 platinum spark plugs and new cop spark plug boots. I am becoming an Autolite spark plug loyalist. Used to think Autolite are cheap spark plugs but now I think they're quality.
 
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