Stock Spark Plugs

[OnyxM400]

Our stock spark plugs:

Motorcraft AGSF32WM

From what I found:

A: 14mm threads
G: .708" taper seat
S: suppressor (carbon)
F: taper seat
32: ? (it's their heat range number, lower the number the colder)
WM: Single Platinum-Iridium electrode




It appears to be used in a bunch of different applications, mainly centering around the 4.6L V8 (including the 2003 Ford Mustang Mach 1 & 2001 Mustang Cobra) and the 3.0L V6 Duratec (our engine, also used in Escape, Taurus, Mazda Tribute, etc). Every single one of those applications are gapped at .054" though. We run .035" (M400) or .040" (GTO-3R). I'm not positive how they're gapped, as you're generally not supposed to re-gap platinum type plugs.

I'm trying to see what other options we have, along with plugs 1 step colder. I'm guessing 1 step colder with the Motorcraft plugs would be AGSF22WM.

[OnyxM400]

Stock heat ranges:

NGK Iridium IX: TR55IX (TR6IX = 1 step colder)
- Electrode size: .6mm diameter
- Max recommended life: 60,000 miles






Denso Iridium Power: IT16 (IT20 = 1 step colder)
- Electrode size: .4mm diameter (with U grooved ground electrode)
- Max recommended life: 30,000 miles




Heat range chart:



More Iridium info:

http://www.spark-plugs.co.uk/pages/t...park_plugs.htm




Brisk Premium LGS: GOR17LGS (GOR15LGS = 1 step colder)

[OnyxM400]

Hmm, gapping instructions:

http://www.densoiridium.com/installationguide.php

IRIDIUM POWER™ GAPPING TIPS

Before attempting to gap any DENSO Iridium Power spark plug, please review the specification chart in the front of this catalog to verify the factory-preset gap. In most cases your Iridium Power plugs do not need to be gapped. Even with small variations in the factory set gap the ultra-efficient firing power design will compensate for those small variations.

Should you decide to re-gap your Iridium Power plug, use extreme caution as improper gapping may damage or destroy the Iridium center electrode or porcelain center.

To increase the gap size:
• Step 1: Use needle nose pliers or spark plug gapping tool to bend the ground strap up to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN.

• Step 2: Re-check the gap with a calibrated gapping tool.

To decrease the gap size:
• Step 1: Use the same method as above, however bend the ground strap down to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN.

• Step 2: Re-check the gap with a calibrated gapping tool. WARNING: Failure to follow these directions may permanently damage the spark plug. Note: Never use a round gapping tool to check the gap or to increase or decrease the gap setting.

WARNING: Failure to follow these directions may permanently damage the spark plug. Note: Never use a round gapping tool to check the gap or to increase or decrease the gap setting.

I guess you can re-gap these plugs, as long as you don't actually touch the electrode.

[dino]

you might check with Corey at AER about plugs. He seems very knowledgable. they have an 800 number.

[RPIpower]

I have always used the NGK R copper plugs on my car. They dont last nearly as long as the platinum ones but I dont mind changing them every 4-5k miles.
Here is a nice read for plug info:
http://www.babcox.com/editorial/ic/ic120214.htm