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 #287721  by user97

I changed spark plugs on my LHs to NGK laser platinums as per FSM -- apply anti-seize to threads, torque to 20ft/lb (240 in/lb). Afterwards, I come across the following on the web: ... isieze.pdf ... e-Compound

From quick Google searches, it becomes apparent that pretty much all spark-plug manufacturers advise against anti-seize. OEM spark plugs appear to have been installed without anti-seize. Did not encounter a seized spark plug on any of my LHs, including the one that had around 180K on ORIGINAL champion plugs. FSM appears to indicate that anti-seize is needed, however, in light of the above, I am starting to wonder.

Any thoughts?
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 #287724  by 300maximilien
I have noticed that cars with aluminum heads that I have worked on ask for AS on plugs when replacing......I dunno??
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 #287742  by Bill Putney
NGK is absolutely FOS stating that anti-seize can cause so much clamping tension that it could cause the plug to break or do any other damage for that matter. Any plug pulled in two from properly torqueing had nothing to do with anti-seize - I promise you that. The plugs in their pictures were over-torqued - period. The fact that anti-seize may have also been used is not an indictment of anti-seize - it's an indictment of the idiot that grossly overtorqued them (perhaps on purpose to get the pictures for the article). Whoever put that together took a huge leap on that one.

All you have to do is find the friction properties published on the better anti-seize compounds and you will see that the change in coefficient of friction over dry torqueing is almost the same - 10% difference at the most - the non-repeatability of torqueing under controlled conditions is way over that. It's not the same as putting plain oil on the threads, and even then, I seriously doubt that will increase the clamping force from the same torque enough to pull a plug apart.'

The main thing to be careful of when putting anti-seize on spark plugs is to not over do it (apply sparingly) and to keep it away from the first 1/8" or so of the threads so it has no chance of contaminating the electrodes and shorting them out by migration or by vapor deposition.
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 #287744  by FIREM
A light touch of Copper Never-Seize, Accurate Torque wrench, and good to go......
 #287748  by user97
Bill, FIREM -- THANK YOU for your re-assurance.

I figured that it would be next to impossible to split the metal cylinder with 20ft/lb -- but it helps to hear other opinions.