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The BGB says 13 ft lbs which is what I usually do. However, The NGK plugs I’m using state a minimum of 18 ft lbs for an aluminum head. 13 ft lbs does seem rather low. What do you all do?
 

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Who uses lube on threads? Or do you mean antiseize?
I use a antisieze product suitable for alloy as well as di-electric grease on the insulator. These products are actually supplied by NGK in small disposable packets. I can dig out a pic if anyone is interested.

While I generally believe torque values should be followed I must admit on spark plugs I always install 'by feel'. Only time I pull plugs is when I'm replacing with new coppers which at my current miliage rate is every 2-3 years. Its very easy to feel the plug meet resistance as the crush washer is compressed. After this point I tighten approx 1/2 turn more to ensure its seated into place. If antisieze is not used then this method may not work as the threads feel sticky and its hard to tell if you are crushing washers or simply binding threads.

Hope that this helps or most likely fuel the debate.

jimb
 

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Anti-seize should be mandatory per the BGB, but it is not. You are mixing aluminum with a chromium based thread on the spark plug. This will oxidize aluminum and cause threads to wear out over time. It is not a lube...it is not really a seize, except that oxidizing (like rust) can weld 2 different metals together. One will always be slightly more anodic than the other. Any stainless steel dress kits bolts on an aluminum valve cover should use the same mandatory process. Always....always...get anti-seize and use it where good. Copper is a good all around one, but their are others. Anyone in construction will know this and building stainless and aluminum stairs requires it to last over time especially in the weather.
 

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Anti-seize should be mandatory per the BGB, but it is not. You are mixing aluminum with a chromium based thread on the spark plug. This will oxidize aluminum and cause threads to wear out over time. It is not a lube...it is not really a seize, except that oxidizing (like rust) can weld 2 different metals together. One will always be slightly more anodic than the other. Any stainless steel dress kits bolts on an aluminum valve cover should use the same mandatory process. Always....always...get anti-seize and use it where good. Copper is a good all around one, but their are others. Anyone in construction will know this and building stainless and aluminum stairs requires it to last over time especially in the weather.
Oh...and not really anything is over 15 ft-lbs threaded into aluminum. Trust the lock washer
 

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Has anyone ever had a spark plug back out on its own? Seems wiser to err on that side thing, eh?
I’ve never had a spark plug back out on its own, but I’d rather have that happen than damage threads in the head.
I’ve used every method of installing plugs in a variety of vehicles in my time, and I’ve only had issues due to previous owners over torquing them.
Now, I install them per the instructions from the manufacturer/service manual.
The guys who made the spark plug don’t know what I’m installing their plug in, so I only use their info if I’m in a pinch.
I agree that anti-seize is good to use for dissimilar metals, but you won’t find me trying to calculate how much torque to add to get to the recommendation.
Like I said, I’d err on the loose side… and I’ve never had any issues.
If you’re really picky about it, get yourself a digital torque adapter and it can tell you what torque your plugs are tightened to… lubed or otherwise.
 

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Oh...and not really anything is over 15 ft-lbs threaded into aluminum. Trust the lock washer
Not true. Just a question of having adequate strength in all parts of the bolted joint. The washer on a spark plug doesn’t “lock” it, it seals it.

Anti-seize should be mandatory per the BGB, but it is not. You are mixing aluminum with a chromium based thread on the spark plug. This will oxidize aluminum and cause threads to wear out over time. It is not a lube...it is not really a seize, except that oxidizing (like rust) can weld 2 different metals together. One will always be slightly more anodic than the other. Any stainless steel dress kits bolts on an aluminum valve cover should use the same mandatory process. Always....always...get anti-seize and use it where good. Copper is a good all around one, but their are others. Anyone in construction will know this and building stainless and aluminum stairs requires it to last over time especially in the weather.
The coating on spark plugs isn’t chrome. It’s primarily a zinc plating. NGK says don’t put anti-sieze on the plugs And they give reasons why. Not sure how that’s a path for disaster. I’ve done it both ways, but a lubricated joint definitely shouldn’t be torqued the same as a dryjoint.
 

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Not true. Just a question of having adequate strength in all parts of the bolted joint. The washer on a spark plug doesn’t “lock” it, it seals it.
I have 10 dirt bikes and 2 street bikes, 2 MR2s, and a Tundra. What I was saying first was that not much is over 15 ft-lbs into anything aluminum in all my manuals, but you took the focus away from that. A crush washer is a type of lock washer that can only be used realistically once.

The coating on spark plugs isn’t chrome. It’s primarily a zinc plating. NGK says don’t put anti-sieze on the plugs And they give reasons why. Not sure how that’s a path for disaster. I’ve done it both ways, but a lubricated joint definitely shouldn’t be torqued the same as a dryjoint.
Dry torque specs are different than wet torque specs for any material. That does not have anything to do with anodic and the properties of different metal types have with each other. Some spark plugs like NGK already have a coating on the threads to prevent issues. Why would they do this? Hmmm....why, because they don't want to risk oxidation over time.
 

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Look on an all aluminum engine, lots of torque specs beyond 15 ft lbs on aluminum threaded holes.

I’m not saying galvanic corrosion isn’t a concern for many fasteners, but a zinc plated fastener in an aluminum internal thread is not a big corrosion concern. Especially in a dry, fairly well sealed application like a spark plug. It’s actually better from a galvanic potential standpoint than a zinc fastener in a steel internally threaded hole.
 

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I have used 19Nm (15ftlb) as per BGB forever, no issues. No anti-seize. Both regularly replaced coppers and long life iridiums, at least a half dozen 3s heads.
 
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