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Car Whisperer
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Discussion Starter · #1 ·
Ok, now that the Iridium craze has died down, what are most N/A's running and when are you changing them. I'm leaning towards Autolite coppers. I know they don't last as long but I have always had good luck with them. Got them now in the Crown Vic and in my wife's Durango.
 

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You have a CV? I want one, then again I want one of everything...

I have the originals in my Bullitt. Motorcraft I assume, I'll have to go look Monday when I'm not working.
 

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I usually run Motorcraft copper plugs, one step colder than stock. I have NGK's in there right now. I can't really tell any difference. I change them way more often than needed, so I couldn't tell you how long they are good for.
 

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Discussion Starter · #4 ·
DavidMidgley said:
You have a CV? I want one, then again I want one of everything...

I have the originals in my Bullitt. Motorcraft I assume, I'll have to go look Monday when I'm not working.
Thanx...yeah got a 99 CVPI for a DD.
 

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Discussion Starter · #5 ·
01GTB said:
I usually run Motorcraft copper plugs, one step colder than stock. I have NGK's in there right now. I can't really tell any difference. I change them way more often than needed, so I couldn't tell you how long they are good for.
Why one step colder?
 

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There is a great article in the Bullitt Archive about spark plugs. There has been a minor change in the design of the original plugs. The thread length has increased in an effort to help prevent "blowout" issues that apparently plagued some of the modular motors....Here is the link...


http://www.bullittarchive.com/1021.htm

Here is a link to Sparkplugs.com which has tons of info and cross references that have helped me quite a bit...

http://www.sparkplugs.com/results_app.asp?productTypeID=1&AAIA=1385636
 

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Frankenstang said:
Why one step colder?
Before my car was tuned it ran a little lean on the top end. In an effort to avoid detonation I went with the colder plug. When I had the car tuned, it was with the colder plugs, so I have stuck with them.

A colder plug, simply put, has the ability to transfer heat more quickly to the cooling system, therby reducing heat at the plug tip. The more ceramic that comes in contact with the metal part of the plug, the more heat it will transfer. Colder plugs are generally recommended for high compression, or boosted and nitrous engines. Sometimes several steps colder. For leaner mixtures and advanced ignition timing, going one step colder (or in some cases, two steps) is common. Plus, all the people who know more than me recommended them :D
 

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Discussion Starter · #8 ·
Great info thanx everyone. Thanx alot for the two links I appreciate that much. Great spark plug site!!!
 

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I ran Autolites for 30k, give or take. Onto NGK now.
All copper plugs.

Both great choices.
 

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I know this is an older thread, and it'll rise again from the dead... :)

I just changed the TR55IX's out of my Bullitt. Nothing to do with the make, the model, or the chemical composition. I've been fighting a "marbles in a can" sound, and ran lean on dyno testing. I've played around with the tune in the car to richen it up but after talking to some tuners, and respected local engine guys, I decided to drop down a step.

I'm sitting with a TR6s (one step colder) and no more marbles in a can.

Mods: JLT Intake, Diablo Tune, Ported MAF. (others wouldn't effect A/F ratio)
 

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those running to autolites, i notice they still have the short threads. is that something to worry about. I know ford changed the motorcraft plugs to help with the plug blow-out problem so i dont know how comfortable i am throwing back in a short thread plug
 

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I'm a little lost, why did Frankenstang mention the iridium craze dying down? Are they bad, or just not good, or what? The reason I ask is because I've been hearing nothing but praise about them, so what gives?
 

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DiZzyBonne said:
I'm a little lost, why did Frankenstang mention the iridium craze dying down? Are they bad, or just not good, or what? The reason I ask is because I've been hearing nothing but praise about them, so what gives?
bump for knowledge..:)
 

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The short threads will not make a difference because it already matches up with the threads that are in the head. The extra threads don't do anything.

HOWEVER it does appear to me that the shoulder of the plug is a little larger on the newer plugs.

Platinum plugs last longer but at the cost of poorer conductor than copper. Iridiums are able to use a smaller diameter and equal the life of platinum with better spark.
 

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Discussion Starter · #15 ·
DiZzyBonne said:
I'm a little lost, why did Frankenstang mention the iridium craze dying down? Are they bad, or just not good, or what? The reason I ask is because I've been hearing nothing but praise about them, so what gives?
I said that because at one time on here, Iridiums were just about the only thing talked about and everyone was getting them and putting them in. Seems now that the novelty of them has gone down and now other types are as discussed as Iridiums. they are considerably more expensive and in the scheme of things, I don't know that they are really worth the expense for a street driven, N/A car. It is doubtful to me that you could tell any difference for cost of admission.
 

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im running the NGK plugs in mine:smile:
 

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Discussion Starter · #17 ·
that's what I bought, haven't installed them yet.
 

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edtrae03130 said:
im running the NGK plugs in mine:smile:
Which NGK's are you running? I'm going to be replacing the plugs in my Bullitt soon, have been wondering what others were running.
 
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