[xk] spark plug threads 3.4l

Interesting. I have routinely used antiseize when installing plugs but do apply it sparingly all the way down, and have had no issues. Much of the antiseize gets pushed upwards as the spark plug is screwed in place so very little remains between the male and female threads and what does accumulate at the seat gets pushed out by the gasket as it seals.

Never a problem stripping threads or changing plugs, but perhaps I’ve been doing it wrong all these years?

I would submit that you haven’t: I don’t know the exact number of spark plugs I’ve changed, but it’s likely in the tens of thousands, and the vast majority of those were done with anti-seize, using exactly the same method that you describe.

Ok, thanks, Wiggs. I’ve just replaced the plugs in the E - I was detecting just a little misfire vibration at low speeds and on inspection a couple of the plugs from different carburetor/cylinder pairs were sooty. Both tested overly high resistance on the mulitimeter so replaced all six. I think I got only 5,000 miles or so on these.

True that little remains on the thread. A probably insignificant measure I take. Main thing is thread by fingers-then not much to tight.

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Do you need to drive it harder, and more!

You have all inspired me to do complete maintenance on my ignition system, measure all plug & lead resistances. I usually let my leads virtually rot away :face_with_open_eyes_and_hand_over_mouth: and havent had a problem, but am more fastidious with plugs, and I always anti-seize them sparingly.

I have seen it written that this is not needed as they come factory coated, but if this is true, then why have I encountered seized plugs, which is nightmare stuff with newer coil over plug engines with the plug in a deep well

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I just spoke with my neighbour, who is servicing a customer Ford F250. 6.2L, supercharged V8. Has a misfire, and one sparkplug disintegrated as he removed it. Customer says replace all plugs please. SIXTEEN of them! Neighbour is not looking forward to this, I had a look, and changing the plugs on a V12 looks like a piece of cake compared to this.

Yea, I read that too.

I always put antiseize on them… :slight_smile:

various web info on antiseize, on nickel plate, on NGK, in alum heads etc. Some say no, some say reduce torque if it is used as it acts as a lubricant. I reduce torque anyway…as previously posted…the key is do not overtighten…finger tight on plugs that thread easily as they should with good head threads…then just a little more to firm. That is it…1/8 or so of a turn if used gasket, maybe half a turn with new. Champion describes it in "flats:. If a torque wrench is used…as I posted before: NGK says: 18-21 ft lb for aluminum head. I would prefer 16-18 in our valuable heads…but no torque wrench used–too easy to go over…ii is 192 inch lb…but I prefer—hand tight, then just a little more…
Nick