Autolite
We do not recommend the use of any anti seize products for installing spark plugs. Anti-seize compounds are typically composed of metallic, electrically conductive ingredients. If anti seize compounds come in contact with the core nose of the plugs, it can lead to a misfire condition. Anti seize compounds can also have a torque multiplying effect when installing plugs. This can lead to thread distortion and thread galling resulting in cylinder head damage. Autolite spark plugs are nickel plated to resist the effects of corrosion and seizing. However, plug seizure is aggravated further when steel plugs are installed into aluminum cylinder heads for a long period of time.
AC/Delco
Do not use any type of anti-seize compound on spark plug threads. Doing this will decrease the amount of friction between the threads. The result of the lowered friction is that when the spark plug is torqued to the proper specification, the spark plug is turned too far into the cylinder head. This increases the likelihood of pulling or stripping the threads in the cylinder head. Over-tightening of a spark plug can cause stretching of the spark plug shell and could allow blowby to pass through the gasket seal between the shell and insulator. Over-tightening also results in extremely difficult removal.
Champion
The following material is excerpted from the Champion Spark Plug Handbook. It can be accessed at:
http://dodgeram.info/Engine-Gas/Spar...plghnbook.html
Champion spark plug shells (the threaded part) use an extruded steel to maintain exact tolerances. The extruded shell goes through a cold rolling process to form the threads. This prevents sharp edges which could cut new threads into aluminum cylinder heads. Once the shell is formed and threaded, it is zinc-plated to extend its life and reduce the chances of seizure in aluminum cylinder heads. Our latest technology combines Tin Tac" and ULTRASEAL'M coatings over the plating to further reduce corrosion and seizure. Champion recommends that you do not use an anti-seize compound, since one has already been applied to the plugs at the factory.
Denso
If a thread lubricant such as grease is coated on the thread, tightening to the recommended torque is tightening too much;
this has been linked to seal leakage.
Do not use a thread lubricant.
http://www.globaldenso.com/en/produc...ion/index.html
Racing Spark Plug Installation:
Do not use anti-seize. To install spark plugs in the engine, first tighten them by fingers, then retighten with the right tightening torques as shown below, using a
plug wrench. Either excessive tightness or looseness will cause troubles. Looseness sometimes causes pre-ignition because heat cannot disperse. On the other hand, excessive tightness can damage the threads of both the cylinder head and the spark plug."
E3
If anti-seize compound is to be used, it should be applied sparingly because this could foul the plug and produce excessive carbon build-up on the threads, as well as give off fumes once the engine reaches operating temperature.
http://e3sparkplugs.com/torque-chart
Bosch
If using anti-seize compound, use sparingly and reduce torque by 30%.
https://www.boschsparkplugs.net/learning-center/article/421/plug-torque-settings
Found one where Anti-Seize is recommended for Industrial use:
Spark Plug Installtion instructions 031412 - Bosch Auto
General Note For Consideration:
Most head damage is caused by a ham handed mechanic who doesn't know what he is doing. Many plugs extend a thread or two into the combustion chamber and can have a buildup of carbon that will destroy aluminum threads if you try to force the plug out. Anti-seize will not prevent this and a reasonable person will stop at the first indication of tightness rather than jump up and down on the ratchet (or use a
hammer) and destroy the threads.
So, the plug will appear to be seized by corrosion when actually the lower threads have
carbon deposits. The plug can usually be removed easily without damage if you un-tighten it 1/8 to 1/4 turn and treat the threads with a mixture of 1/2 acetone and 1/2
power steering fluid (or other penetrating oil/fluid and/or
carburetor cleaner). With luck, the mixture will be wicked into the threads and help soften the carbon. Let the plug sit over night and try again (working it back and forth, and if needed treat it again).
Install a plug by seating it finger tight and turning as specified by the manufacturer. This will provide the correct torque whether the
spark plug threads are dry or treated with anti-seize. Engine oil or grease used to lubricate a spark plug thread (and in many anti-seize compounds) can carbonize and stick a plug. Misfire is also possible should anything used end up on/near the plugs firing end.