First, SAE and Machinists Handbooks are as definite reference sources as you will ever find. Service manuals are derived from them , not the other way round. I'm one of the engineers who prepared service manuals and never decided otherwise.

Second, Specified torque values are never changed just because the threads are dry or lubricated; they are always specified as lightly lubed. The variation in dry friction is far too great to ever be used. You quote 0.2 but I've measured 0.2 to .5 friction coeffients on dry threads compared to .18 to .24 for lightly lubed. Which one would you suppose would bugger the threads or freeze? One of the first things to look for when bolts are forceably removed is the condition of the threads. If the threads show signs of being actually undertorqued by thread engagement, there is reason to believe they were subject to loosening. Thats what happens when threads are torqued dry; the force to turn the thread is much greater than it should be. Hence higher torque readings than actual.

Third, It is true that the smaller the thread diameter and pitch the less absolute difference between applied torque and actual torque. For plugs with only 25 lbft the difference is small at 1 ftlb but important to thread retention because the rfriction is so variable there no way to be certain just what you have applied. Whem threads are dry the torque applied is greater than actual, and often much greater; so the acual torque is too little.

Fourth, I have several NGK engineers on my acquaintence list and all lightly lube spark plug threads. At least at the track. I know more than a few Honda engineers and they do the same.

Fifth, calling spark plug bases as a shell is as inaccurate as calling schedule 40 pipe a shell. A quarter inch wall on a one inch diameter is hardly a shell.

 

Sorry but you are wrong. Stop misinforming readers. If you have an opinion, that's fine, but state it as such. I've stated facts and references. You've stated your opinion as fact. Torque whatever you want however you want, but don't tell readers that dry vs oiled makes no difference.

You are dead wrong in thinking torque specifications for a fastener are not respective to oiled or dry. You simply fight physics and the world of engineering.

I quoted NGKs recommendation to not use anti-seize. You do not have better data, analysis, or information. http://www.ngksparkplugs.com/pdf/tb-0630111antisieze.pdf Why should we listen to your opinion and not the PUBLISHED recommendation of the MANUFACTURER of the plug RECOMMENDED by Honda? Am I missing something?

I quoted the google search to look up dry vs wet torque specs. I invite you to do your own search. Here's one. http://www.machinetoolhelp.com/Repai...que-chart.html Per that web site a 1/2-13 grade 5 bolt has a 20 ft lb difference between oiled and dry - 55 for oiled, 75 for dry. That is huge! Shablam! Do you understand that a fastener is a spring used to clamp parts together? Threads on a bolt are simply the cam mechanism to stretch the bolt to certain tension based on it's material and size. Changing friction in that cam mechanism changes the stretch for the same given torque wrench value.

Here's another article showing how anti-seize can be determinantal if its not specified. http://benmlee.com/4Runner/threads/threads.htm

You quote no reference other than the words "SAE" and "Machinist". Show me the documented reference you purport supports your belief. "I've always done it this way", or "my Honda engineer friends do it that way" is not valid. I've shown you document evidence of what I'm talkin about.

One more thing. I do this kind of thing for a living. I analyze, test, and derive specifications for multi-million dollar products, including torque specifications for specialty hardware. I know what I'm talking about. But even if you think I don't, I've provided the evidence.

Here's the final word: My 2007/8 pdf manual, page 2,681, states the following: "Apply a small amount of anti-seize compound to the plug threads, and screw the plugs into the cylinder head, finger-tight. Torque them to 18 N.m (1.8 kgf.m, 13 lbf.ft)." NGK web site states Spark Plug Installation Instructions to torque between 18 and 21 ft-lb (for our 14mm plug size) with NO mention of anti-seize. The instructions are very succinct and there's NO talk of oiling or anti-seizing the threads. That is a 65% difference in torque between what the manual states with anti-seize and what NGK states dry!!! The defense rests.

 

I've lost count of the years that I've been using ant seize compound when assembling engines, transmissions, exhaust,components and intake manifolds, brake parts and suspension components ... Any motorcycle I was constantly changing out stock pieces for performance pieces were always reassembled with anti-seize compound...I have no problem pulling my spark plugs to see how they are doing and always wipe the threads with a shop towel and reapply the anti-seize compound when I do... If I ever heard of anyone that experienced a problem by using the stuff I can't remember it. We even used it on aluminum handle bars, stems and seat post clamps as well as cables, shifters and sealed bearing hubs at my on high end bikes at my bicycle shop... The stuff doesn't dry into a powder and attract moisture like expensive Campagnolo white lithium grease that people that owned Campi gruupos insisted that we use... I never argued with them and gave them what they wanted and made a lot of money stripping down their expensive bikes and replacing the "yuppy grease" annually..

 

Well said.

 

I have 3 engineering degrees and 27 patents; worked for and suppliers to Detroit and Honda and Toyota and owned 2 service shops in 50 years. I am in the world of engineering. There are more than 33 vehicles that I contributed engineering expertise; not one specified torque on dry threads. We knew the hazards of doing so.
Your gobblygook is like ther poor woman in the TV ads.
You cannot find a definition in any engineering text that proclaims dry threads will be properly torqued. i seriously doubt you have ANY responsibility for torque specifications. The stuff you quote is not a spec, merely measurements and I didn't see the tatistical analysis for stuff like plus/minus 3 sigma at least..
So is your manufacturer or the spark plug manufacturer recommendation, not a requirement, whose engineers don't follow the non lubed process correct ?
You have no defense you are merely posing.
One of our guys (we try to keep him away from customers who brought grief on themselves) called out NGK tech guy and told him what you said. His reply was short and to the point: 'horsehockey. And is we don't recommend anti-seize lubes its because some will slop the lube on sloppy enough to possibly interfere with electrical conductivity but we've never seen thast happen. And we don't countermand manufacturers'. Personally, I don't care if you want torque dry threads but others should be aware of the specifcations set by engineers in their Tech manuals, SAE and Maxhinery Handbooks in particular.

Obviously you aren't aware that SAE is Society of Automotive Engineers and the Machinery Handbook is published by Industrial Press. You can look up thread torque specs in both yourself. Take close notice of the credits.
cheers.

 

Never used any kind of lube on plug threads or wheel studs and I've been around the block a few times.

 

This thread is now horses

 

 

 

 

 

 

 

And did you just tighten as thight as your strength allowed too.
More than a couple of showroom stock racers found out thehard way with wheel separation.
Thats not saying you have to torque properly in steps back and fou th with lightly lubed threads, its just safer. Yoiu're not alone in not lubing threads, you just didn't have wheels losen or spark plugs blow out.

 

 

Our fit had a spark plug blow out at 40k... Stripped the threads on its way out. New head was installed as part of the warranty...

 

Thanks for this link. I've always (since the advent of aluminum heads) used never seize on spark plugs. Now that I know NGK recommends against it, I won't use it on their plugs. I'm sure NGK has engineers that are knowledegable about their products. Using lube on fasteners is a good practice, however when a component manufacturer recommends against it, sounds like good advise to me. Better check with Claymore for the final and correct answer though.

 

Wow, I'm gonna feel bad for embarrassing you. You're not an engineer. You're a troll with a chip on your shoulder.

Why dont' you look at Machinerys yourself smart one? Ok, I'll do it for you. Machinerys Handbook 25th edition, section titled torque and tension in fasteners, page 1,403, Table 1 titled coeff of friction of bolts and nuts. u=.07 for oiled steel. u=.17 for zinc plated steel. Can you do 3rd grade math? If so you'd find that friction gets reduced by 1/2 if you lubricate threads.

You say you called some NGK guy and he said what his company wrote and published on the internet with their company logo is wrong? Therefore he's right? You sir have demonstrated your incapacity to think.

But of course, like I wrote before, the world is wrong, and you're right. Here's another article about not using anti-seize (when it's not specified) that you will say is wrong. http://benmlee.com/4Runner/threads/threads.htm

 

Agreed. However, that doesn't mean what NGK states or the rational behind dry torque vs wet torque being different is wrong. That's my only point. Here's yet another anti anti-seize argument. I think most of the time you're just within the bounds of the torque spec to use anti-seize, meaning that if the spec was to allow for 50% preload, you could conceivably double that and still be on the hairy edge of success. http://benmlee.com/4Runner/threads/threads.htm

 

mahout who generally seems to know what he is talking about, has been making posts of questionable content with greater frequency lately.

The disconnect in understanding the relationship between torque production and spark angle (on the subject of knock-retard) was the one that tipped me of that someone may not be firing on all 8 anymore...