there is not a single person here or anywhere that will ever convince me that antiseize on plugs is a bad thing. on every single plug i've ever put in, i cover the bottom 3 threads with antiseize and have never had a minutes trouble.
OK, how about the spark plug manufacturers themselves? They all agree:
First, 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. BTW, the fact that someone pulled more plugs than Charlie's dated **** stars doesn't mean he is doing it correctly.
NGK recommends:
"Do not use anti-seize. Anti-seize reduces electrical and thermal conductivity between the spark plug and head; and increases the installed torque, which can damage head threads. The spark plug holes must always be cleaned prior to installation, or you may be torquing against dirt or debris and the spark plug may actually end up under-torqued (dry threads), even though your torque wrench says otherwise.
All NGK Spark Plugs are manufactured with special shell plating on the metal body. The use of anti-seize on spark plugs is only recommended on those brands that do not offer a special metal shell plating. Install spark plugs with a compression gasket finger tight until seated and then turn approximately 1/2 to 2/3 turns. Spark plugs without a compression gasket (taper) should be installed finger tight until seated and then turn 1/16 turns.
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."
Champion recommends:
"Champion recommends that you do not use an anti-seize compound, since one has already been applied to the plugs at the factory. Next, install the spark plugs finger tight and, if using a taper seat spark plug, use a ratchet to rotate 1/16 of a turn. If using a gasket seat type spark plug, after installing finger tight, turn 1/4 to 5/8 of a turn. If this procedure is followed, spark plugs will not back out nor will they seize in the cylinder head."
Autolite recommends:
"We do not recommend anti-seize. Install 14mm plugs in aluminum cylinder head at 20-30 Nm (15 - 22 foot pounds) with CLEAN and DRY threads. 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 on the threads of your spark plugs will slow down the rate of heat transfer from the plug to the head. The worst place to use it is on the tapered seat, which is where the most heat transfer occurs between the spark plug and the cylinder head. Even just a small amount of anti-seize is the equivalent of using a hotter heat range spark plug.
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.
NOTE: Spark plugs should be installed with clean and dry threads to avoid over-torquing or stretching the spark plug, which can, and often does, result in engine damage."
Denso recommends:
"Do not use anti-seize. Installation Key Points: (1) The threaded area of the cylinder head must be clean. (2) Using your fingers, screw the spark plug into the cylinder head, and tighten about 1/4-1/2 turn with a plug wrench. (Taper seat plug: about 1/16 turn). (3) Tightening too much may cause distortion of the plug housing, and in extreme cases could cause engine damage. Proper installation of the spark plug is important for life and performance of the spark plug. (4) Installation procedures shown above apply to new spark plugs without lubricating the threads.
Torque Recommendations (dry threads). Whenever possible it is recommended that the spark plug should be installed by using a torque wrench. "
Bosch recommends:
"Do not use anti-seize. Bosch small engine spark plugs are constructed with a nickel chromium ground electrode for consistent performance and prolonged service life; Nickel-plated rolled threads offer complete anti-seize and corrosion protection. Built to withstand extreme operating temperatures and give more power, Bosch Super Start is ideal for all small engine applications."
