Autolite is the manufacture of the Motorcraft plugs and they have a removal bulliten
You are supposed to be able to remove the plugs without breaking.
Service Procedure - Removal
Thin wall 9/16” spark plug socket, various length extensions
and ratchet. (Do not use a standard deep well socket)
Beam or dial style torque wrench, (non clicking type)
Carbon dissolving carburetor cleaner.
Compressed air and blow gun.
IMPORTANT: You MUST adhere to this procedure exactly to
prevent breaking spark plugs during removal! Engine must
be completely cold (room temperature) before beginning.
Spark Plug Removal
- Remove coil on plug assemblies and set aside. Using compressed air and shop vac, clean spark plug wells of all dirt and debris.
- Using a ratchet, back out each spark plug 1/8 to 1/4 of a turn. Fill the spark plug well with carburetor cleaner to just above the hex on the spark plug. (½ to 1 teaspoon) (see illustration #2).
- Allow a minimum of 30 minutes soak time for the carb cleaner to wick down to the ground electrode shield and soften the carbon deposits at this time.
NOTES: Review the product label on the carburetor cleaner and adhere to all precautionary statements. Use at room temperature with appropriate PPE, (personal protective equipment).
- Tighten and then loosen the spark plugs working them back and forth to remove. Use the beam style torque wrench and do not exceed 33ft. lbs. removal torque (see illustration #3). If more than 33ft. lbs. is required; place an additional ½ teaspoon of carb cleaner in the well and wait another 15-30 minutes for the carbon to dissolve.
- Repeat the back and forth effort working the spark plug loose. Some screeching and high effort will be noticed. Remove the spark plugs.
- Using the shop vac and a small hose, clean out the plug well and combustion chambers of excessive carb cleaner.
WARNING: Excessive carburetor cleaner in the combustion chamber can cause the engine to hydro lock, remove as much as possible.Spark Plug Installation
- New plugs should be installed using a thin film coating of high temperature nickel anti-seize on the ground electrode shield. DO NOT coat the ground strap. (see illustration 4)
- Tighten spark plugs to 25ft lbs.