I think I overtighted my spark plugs...

I did spark plugs recently on the Mini. Aluminum head. I'm new to torque wrenches so I set it at the correct torque setting but it seemed to take too many turns to tighten to 20 lb/ft. After doing some research, I think the extra turns might have come from using a spark plug socket and extension and some anti-seize.

Will I be hosed if I remove the spark plug? Will the act of removing it cause damage to the threads?

Minis have reported blowing spark plugs out of the head b/c they were overtightened, hence my concern.

Thanks for your input.

I don't think it sounds like you did anything wrong.

In general, using an extension with a torque wrench isn't considered the best practice...but frankly, torque wrenches aren't the best method for applying torque anyway (though they are usually the best we've got)...that is to say, while the wrench may be calibrated and accurate, in reality, the bolt will get torqued in the range of +/- 25% of the setting anyway.

I don't think Anti sieze should affect your torque application.

Clem

My father always said that if you needed a torque wrench, you were doing it wrong anyway.

By using the lubricant, you changed the torque values by approximately 20%. So instead of 20ft/lbs, you're probably around24-25ft/lb.The spark plug socket and extension do not alter your settings- the extension is centered,thus your torque does not change.I'm not a(new) mini expert, but my guess would be leave them alone.

Did the spark plugs have one of those crush washer things on them? That would account for the "extra turns" before it met torque.

I think I understand what you're saying now...

You're concerned because it felt like you stripped the threads? Is that right?

There would be no harm in pulling the plug back out to check...if the threads are stripped the damage is done.

I sincerely hope that isn't the case, and can't imagine it with 20 ft*lb. This is also assuming that you started the threads by hand.

I'm betting on the washer things causing the strange feel.

Clem

Do the plugs have some kind of "crush washer" that seals against the head? If so, that might be why you seemed to be "too many turns" from the point where spark plug touched the head and when it reached the final torque.

You're fine. As others have said, an extension doesn't affect the torque values. Lubricant does, but not enough to strip a thread.

Don't most torque specs for spark plugs call for inch/lbs, not foot/lbs?

ZOO wrote: Don't most torque specs for spark plugs call for inch/lbs, not foot/lbs?

If it has those washer things on the plugs, it will take a bit more torque than normal.

I quit using torque wrenches on spark plugs with crush washers. Hand tighten, and then the socket. You can feel the crush washer actually crush, and this is the torque spec. I always use anti-sieze on spark plugs, pulling them out of aluminum heads after extended periods I always appreciate the lubricant later. And I don't have to adjust the "feel the squeeze" torque setting.

Naw, there's no damage. You'd have to tighten the snot out of them for anything to break and then it's more likely to break the threaded 'barrel' off of the plug (learned that the hard way as a kid).

Those crush washers make for an inaccurate torque reading, hence I don't use a torque wrench. Instead, I use the olde tyme method: new gasketed plugs go in finger tight till they stop, then get 1/3 turn more. Reusing gasketed plugs, max of 1/4 turn since the gasket's already been compressed. Taper seats, finger tight then 1/16 turn. Thoroughly cleaned threads and anti seize in every case. I can't say enough good stuff about anti seize.

In reply to Jensenman:

Thats how I typically do it also.

The Mini is the first new car I've ever owned so I was trying to do it "by the book". Its also the first non-rotary powered car I've worked on in many moons.

Thanks for the help. I'll loosen up the plugs tomorrow and re-tighten.