This maybe because the anti-seize compound can effect the readings, while you are torquing down the spark plug. Causing over-torquing and thread (not head) damage.

 

Yes, I know lubricant would increase the effect of torque. But its just 20LB-FT...

I think the spark plugs are a M14 thread? Same as an oil pan drain bolt. And those bastards get torqued to 30LB-FT (or worse), every oil change.

And no... cylinder pressure wouldn't explain any differences.

But I'll take the man's word for it since I've not actually used anti seize on a S2000's spark plugs, and I don't ever plan to need to.

 

I seem to recall Billman once reporting he experimented with an unusable, damaged head, testing how much plugs could be torqued before any damage occurs.

IIRC, he made it all the way to 70 lb/ft. Dry.

If you use antiseize your 20 lb/ft ends up over torquing the plug. But surely it doesn't get anywhere near the equivalent of 70 dry, right?

So then what's the issue?

 

See post #27.

Quote:

For the record, I did a torque test on a stock head and stock plug. Starting at 15 ft-lbs, I increased the torque by 5 ft-lbs each time to see what the threads could handle.

I reached 80 ft-lbs, and the spark plug threaded portion broken off the spark plug. The head suffered no damage at all.

This makes 24 ft-lbs a solid number you can take to the bank.

End quote

Quote from an article:
The Loctite people recommend reducing applied torque by 20 percent from dry values when using their liquid thread-locking compounds on threaded fasteners. You can find tables of wet-vs.-dry fastener torques in places like Thomas J. Glover's "The Pocket Ref" (inexpensive, used, on Amazon), but judging from the values given, a fair estimate would be a 25 percent reduction in torque when tightening an oiled or anti-seize-treated fastener.



Some other articles on this. First one mentions "anti-seize" as a lubricant.

https://www.hextechnology.com/articl...ricant-torque/

http://www.antiseize.com/PDFs/torque_specifications.pdf

Here is a video by NGK 2 minutes long why you should NOT use anti_seize unless you have a black oxide finish on the plug. (Not ours). They warn against everything Billman is warning about.

 

Ah yes...duh.

Spark plugs are hollow and probably not a C10.9 steel.

Makes sense now.

Don't use anti seize and use 24LB dry.

 

Drill Sergeant Billman:
B Serious Gump! What's your sole purpose in this forum?

Forrest B Serious Gump:
To do whatever you tell me, drill sergeant Billman!

Drill Sergeant Billman:
God damn it, B Serious Gump! You're a god damn genius! This is the most outstanding answer I have ever heard. You must have a goddamn I.Q. of 160. You are goddamn gifted, Private BSerious Gump. Listen up, people...you put these spark plugs in DRY! You got it?

Forrest B Serious Gump:
Now for some reason I fit in the forum like one of them round pegs. It's not really hard. You just make your S2000 real neat and remember to stand up straight and always answer every question with "Yes, drill sergeant Billman."

 

^Its a good plot...I'm just not that great at shrimpin