Correct. When Bill and I corrected multiple loose plugs at the Dragon, it was people who had supposedly torqued them "properly". Now whether that was due to improper torque technique or out of calibration torque wrenches, I'm not sure. But the way I do them, as an extra safeguard is to tighten them fully by hand just until they stop turning, and then torque to 24 ft-lbs. I have had a few where if the threads are just dirty enough my torque wrench, which is properly calibrated (3/8" drive, in-lbs set to 288), will click but the plug itself hasn't fully crushed. This is why I revised my methods to ensure 100% that every vehicle I work on has adequate torque on the plugs so nobody has any backing out, melting of electrodes, frying of coils, destroyed cylinders, etc.



Yes, I should make note that this is only necessary on a new set of plugs. The washers can definitely be reused and simply installing and torquing right off the bat will be fine as the washers will have already been crushed. Also, on a new set of OEM plugs, don't use anti-seize as they have a Trivalent plating to keep them from seizing. Successive installations of used plugs you can use a dab to keep them from getting stuck in the head. (Not a huge issue with the S2000 since the head is aluminum and plugs are steel)

 

Picked up a TQ wrench. This is the first time this has happened to me but thank you for the info Billman250. Haven't had a chance to pull the head off because of the bad rain. Dreading to find out what the bottom end will look like

 

I have been using the previously revised recommendation of 18-20 ft lbs , I haven't been following this topic long enough to see the 24 ft lb spec. I'll double check mine this weekend. Thanks

 

I can also attest to 24 ft lbs being correct. I installed new plugs last year and used 20 ft lbs, after around 5 months the car started running badly, did a valve adjustment and found one of the plugs took barely any effort to remove, the coil was perfect so I thought nothing of it. Another couple of months I started getting a valve tick, thinking I didn't tighten one of the jam nuts all the way I removed the plugs again and noticed the plug that was sort of loose the first time(which I moved to another cylinder) had part of the ground strap disintegrated like the first picture, but MUUUUCH less severe, just the corner had ablated. I immediately went to get new plugs from the dealer, and after checking the cylinder with a boroscope for damage, and setting my valve clearance(one of the valves on cylinder 4 was at .010") I put it all back together, car is running fine, for now. New plugs, re-installing plugs, no matter, 24ft lbs + a little pull at the same force to make sure the plug is seated, and you'll never have a problem.

 

Oh darn it! I just followed this how-to and only have my plugs tightened to 18 ft/lb. Will go back and re-torque to 24 ft/lbs when the engine has cooled off this evening.

https://www.s2ki.com/s2000/topic/765...ug-change-diy/