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Hi folks, just wondered if anyone has had any experience or insight regarding the following. I changed the spark plugs on my '86 230F engine, using anti-seize on the new spark plug threads (I read the FAQ regarding why anti-seize is bad, but many other sources say that it is helpful and even necessary in an aluminum head; moreover, I've had experience with seized plugs and it is not something I want to repeat). I started all the plugs by hand. I torqued them to about 13 ft/lbs, the lower-than-standard value being used to compensate for my use of anti-seize.
Now here is what was odd. After the torque wrench first clicked on the #3 and #4 plugs, I rechecked the torque and was able to turn them about another 3/4 turn before the torque wrench clicked again! The resistance did not really increase much as I kept turning. Finally, the torque wrench clicked again after a nearly imperceptibly slow increase in resistance. On the #1 and #2 plugs, once the torque value was first reached, the torque wrench clicked immediately if I tried to turn the plugs further.
In a nutshell, my biggest worry is that the threads are stripped on the #3 and #4 cylinders. Otherwise, I wonder if the anti-seize allowed me to keep turning the plugs that far without a corresponding increase in resistance. But then why didn't that happen on the #1 and #2 plugs? The only theory I can muster to account for this difference other than stripped threads is that perhaps the anti-seize got under the gasket rings of the #3 and #4 plugs but not under those of #1 and #2. It may have required force to press out the anti-seize that was under the gasket ring (hence the extra 3/4 turn without much increase in resistance), until the ring finally seated against the actual cylinder head. But this theory is really just to make me feel better - I really have no idea what happened or if this is common or if I seriously screwed something up or what. Should I back them out and retorque them? (Using bosch plantinum plugs btw.) Any shared experience/wisdom is greatly appreciated.
John
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