Spark plug torque

slamfire

Original poster
Member
Apr 9, 2013
3
I'm afraid I over torqued my new plugs on my I6 '04 Trailblazer. I used a 3/8 drive spark plug socket and gripped around the head of the rachet with the extension in-between my index and middle fingers to simulate using a stubby rachet. I didn't try to torque them down super hard, but my wrists are pretty strong and this is my first time doing this, thus I don't have a good feel for ft. lbs. Do I say forget it and let them ride, or do I go out and get a torque wrench and torque it down to 16 ft. lbs. like it says? Thanks in advance.
 

triz

Member
Apr 22, 2013
746
Harbor freight sells a Torque wrench for like 10 bucks with the coupon in any car magazine. If you don't have one "hand tight" is what your looking for.
 

CaptainXL

Member
Dec 4, 2011
2,445
The service manual says 13 ft/lbs or 156 in/lbs. Clean the threads by shooting some carb cleaner (without straw) down the hole for a more accurate torque.

I got the $10 Harbor Freight in/lb torque wrench a month ago. Works great.
 

TangoBravo

Member
Dec 5, 2011
208
CaptainXL said:
The service manual says 13 ft/lbs or 156 in/lbs. Clean the threads by shooting some carb cleaner (without straw) down the hole for a more accurate torque.

I got the $10 Harbor Freight in/lb torque wrench a month ago. Works great.

I usually use the anti seize as a lubricant for accurate torque.
 

CaptainXL

Member
Dec 4, 2011
2,445
TangoBravo said:
I usually use the anti seize as a lubricant for accurate torque.

I never use antiseize on spark plugs. I have heard it will change the heat rating of the plugs. I've never had problems getting plugs out of any engine. And I have worked on engines that were very old and rusted.

In the military we learned that adding any type of lubricant to a threaded section will throw torque readings off.

That's why I recommended to clean the threads prior to torqueing.

NGK recommends:
"Do not use anti-seize. Anti-seize reduces electrical and thermal conductivity between the spark plug and head; and increases the installed torque, which can damage head threads. The spark plug holes must always be cleaned prior to installation, or you may be torquing against dirt or debris and the spark plug may actually end up under-torqued (dry threads), even though your torque wrench says otherwise.
 

tblazerdude

Member
Dec 4, 2011
321
in mechanic school, and all the guys i work with, and every tune up i've done, EVERY SINGLE spark plug must have a SMALL amount of anti-seize on it. I would say I normally apply it to a 1/4 of the threads. Now if your intervals on plugs are 30-50k (not 100k like on our 360's) then the anti-seize might not be necessary. I find it hard to believe you have never had a difficult time getting spark plugs out. I have had to extract spark plug threads from engine blocks countless times. It is one of the least fun things to do, and you always run the risk of getting debris in the cylinder. My other most hated - broken exhaust manifold bolts.
 

Denali n DOO

Member
May 22, 2012
5,596
tblazerdude said:
in mechanic school, and all the guys i work with, and every tune up i've done, EVERY SINGLE spark plug must have a SMALL amount of anti-seize on it. I would say I normally apply it to a 1/4 of the threads. Now if your intervals on plugs are 30-50k (not 100k like on our 360's) then the anti-seize might not be necessary. I find it hard to believe you have never had a difficult time getting spark plugs out. I have had to extract spark plug threads from engine blocks countless times. It is one of the least fun things to do, and you always run the risk of getting debris in the cylinder. My other most hated - broken exhaust manifold bolts.

post above, NGK says using anti seize may result in over torquing, maybe that's why they're hard to get out?
 

tblazerdude

Member
Dec 4, 2011
321
Denali n DOO said:
post above, NGK says using anti seize may result in over torquing, maybe that's why they're hard to get out?

Rarely, if ever (except my own vehicles/family members) have I done plugs more than once on a car. I can tell you that the ones that have anti-seize come out much easier, and the ones that don't are tougher. You can usually tell. I've also always used a Torque wrench, and you really believe that anti-seize can effect the ft/lbs being applied by the torque wrench? By how much? The harbor freight Tq wrench is +/- 6 ft lbs I believe, (im not knocking it I have one) and you think anti-seize has the ability to change the amount of pressure you are applying to the bolt by more than 6 ft lbs? Doubtful. It's just liquid graphite, it's not super magic make you over torque everything juice. Just my $.02

I can't stress enough how I said a small amount. 1/4 of the threads, at most.
 

TangoBravo

Member
Dec 5, 2011
208
If you use ngk in our I-6 you have more issues then possible over torque do to anti seize.
 

TangoBravo

Member
Dec 5, 2011
208
CaptainXL said:
In the military we learned that adding any type of lubricant to a threaded section will throw torque readings off.

REALLY, I am curious then why does Rolls Royce, Pratt Whitney, Allison, and Rolls Wood all state that if anti seize is not used on thier multi million dollar turbines they will not warrenty ANY failure? I've been sent to these schools by my company and they all state this disclosure.
 

CaptainXL

Member
Dec 4, 2011
2,445
TangoBravo said:
REALLY, I am curious then why does Rolls Royce, Pratt Whitney, Allison, and Rolls Wood all state that if anti seize is not used on thier multi million dollar turbines they will not warrenty ANY failure? I've been sent to these schools by my company and they all state this disclosure.

Exactly how do multi-million dollar aircraft using igniters in a turbine engine compare to consumer grade automotive spark plugs in a vehicle? That's a totally different industry.

tblazerdude said:
I can't stress enough how I said a small amount. 1/4 of the threads, at most.

I've already researched this dozens of times before. Have had GM vehicles for most of my life.

Show me where GM or AC-Delco recommends anti-seize using the Iridium plugs or any other plug for that matter. I may change my mind. Somehow I don't think that's going to happen here. There are tons of pros on BITOG and various other tech websites that state NOT to use anti-seize. THAT is how I came to the decision not to use it.

If you truly understand the warning that the manufactures and engineers express concern about you wouldn't do it either.


TangoBravo said:
If you use ngk in our I-6 you have more issues then possible over torque do to anti seize.

In vehicle applications applying anti-seize is a torque multiplier. Do it and you risk thread damage as NGK and most other spark plug manufacturers say. Especially when used in combination with aluminum heads.

Give me any compatible cross-referenced plug with the correct heat range and reach and it will work. It's kind of misleading to say that X plug won't fire correctly in an engine. Research needs to be done. I've done it and have been found guilty of choosing the wrong plugs. It's easy.

As I said before pretty much most if not all automotive spark plug manufacturers say not to use anti-seize. Look it up yourself and you will see.

If you pay attention to the specific application at hand (automotive spark plugs) you will notice the logic here.

Take a look at this statement again:

"Anti-seize reduces electrical and thermal conductivity between the spark plug and head."

If you truly understand electronics and the thermodynamics involved in heat transfer between similar or dissimilar metals you would have no choice but to agree with the engineers.

I am not about to get into a pissing match here about what specific applications are designed to be wet vs. dry torqued and the like.

All I can comment on is what's generally acceptable in the industry when installing automotive spark plugs. Now if you want to use anti-seize on your spark plugs and or private plane or favorite hobby or engineering product, be my guest. Not going to complain. I just happen to agree with the spark plug manufacturers and I thought it should be known.
 

Playsinsnow

Member
Nov 17, 2012
9,727
For arguments sake, not that NGK should apply to any of us, but the idea is the same. For the record I use it whenever someone hands me some :biggrin:

http://www.ngksparkplugs.com/pdf/TB-0630111antisieze.pdf

And I believe the disclaimer for the Rolls is aimed towards the repair shops, cutting every possible angle not to warranty a fix. Can't imagine a rolls owner changing the plugs to begin with. That might void the warranty:rotfl:

And like she said, too much lube is never a bad thing! Whatever rocks your boat!
 

Sparky

Member
Dec 4, 2011
12,927
I've never used anti seize on any of my plugs, and the factory plugs I pulled never had any. Never really had a problem pulling plugs either.
 

Mark20

Member
Dec 6, 2011
1,630
Years and years ago a short auto maintenance course taught me to use anti-sieze. Now I'm having second thoughts. As I'm coming near to needing to replace the Voy's plugs, I'll have to see what - if anything - they have on the threads.
 

TangoBravo

Member
Dec 5, 2011
208
The industry does not matter when you state that anti seize is a multiplier. Nuts and bolts are nuts and bolts regardless of what you use then on and how you use them. What you state is that using anti seize changes the torque value because it is a lubricant. So why would your method of thought not cross over to any other torque application? A lubricant would be a lubricant on anything you torque if your method was true.
 

STLtrailbSS

Member
Dec 4, 2011
1,617
Plugs Tight, Gas Pedal Floored, Mouths Shut, Listen to the 135mph wind
-My take on changing plugs
 
Jan 21, 2012
58
when you torque something with a torque wrench it does not change the torque either lubed or not BUT what it changes is the clamping force that the nut, bolt etc.exerts on the unit this why you should not lubricate the threads if they say Dry torque, you could strip the threads. The engineers do calculations out the wingwang to make sure that things are the right tightness.
 

slamfire

Original poster
Member
Apr 9, 2013
3
Thanks for the replies. I never knew there was so much controversy on anti-seize vs. no anti-seize. I have an inch pound torque wrench that I use to torque my rifle stocks but didn't have a 1/4 to 3/8 adaptor to make it work with my spark plug socket. I got an adaptor today and torqued my plugs (thanks, jrSS, but I was curious). I believe I had them torqued between 13-16 ft. lbs. I did use anti-seize originally. I did not clean my threads.

Oh, and my #3 plug had a bunch of fresh oil on it, so I guess I have a leaky valve cover. The ground electrode was a bit darker on this plug compared to the others, which looked great. Due to the pooled oil in the well?
 

CaptainXL

Member
Dec 4, 2011
2,445
TangoBravo said:
The industry does not matter when you state that anti seize is a multiplier. Nuts and bolts are nuts and bolts regardless of what you use then on and how you use them. What you state is that using anti seize changes the torque value because it is a lubricant. So why would your method of thought not cross over to any other torque application? A lubricant would be a lubricant on anything you torque if your method was true.

My caution isn't so much the torque involved here (many of us wrenches pretty much know better). It's pretty difficult to turn a bottomed out tapered seat plug more than a few millimeters. Rather it's the thermal and electrical issues that give me pause.

Initially I just couldn't resist commenting from what you typed. Didn't think it would cause all this discussion. I guess I should have just commented with the following...

TangoBravo said:
I usually use the anti seize as a lubricant for accurate torque.

I can see how one might think this is the case. But it's been proven that this is not true. Dry/clean threads offer the most accurate torque.

tblazerdude said:
The harbor freight Tq wrench is +/- 6 ft lbs I believe,

Just looked it up on their site. It's a +/-4% error. Many in the comments section praise the accuracy. And the ft/lb torque wrench shouldn't be used. Use the inch/lb one. 13 ft/lbs is too low on the scale to be useful in the ft/lb range. Remember it's 156 in/lbs.

Here it is:

http://www.harborfreight.com/1-4-quarter-inch-drive-click-type-torque-wrench-2696.html

Once you set and torque the plugs you will be kicking yourself seeing how much little torque is actually needed to tighten these bad boys. Pretty much had an "oh crap" moment knowing I was tightening them so much. The aluminum heads are not forgiving.

And for those of us that think that removing these plugs down the road will be hard without lube. Well...um don't think so, no way, not with this low of a torque requirement.
 

seanpooh

Member
Jan 24, 2012
461
I have heard the same about using a lubricant on the threads will affect the torque needed to apply. As for my last two spark plug changes, I haven't used any anti-seize and they came out fine until the thread came up about the spark plug breaking in the cylinder head. I went to the store and got some anti-seize.

I also read that you leave about a 1/4 inch at the spark tip with none applied and apply the rest of the spark plug with anti-seize. Then when tightening the spark plugs, I hand tighten them with moderate force. I did notice that with anti-seize, I can turn much more.

I do use the anti-seize on the drain and fill plugs of the transfer case, front and rear diff. I want to make sure I get them out the next time. Pretty much on any nut or bolt that I want to remove next time except places that need loctite.

All in all, I haven't noticed any problems when using anti-seize with the spark plugs. I also did remember to use a dab of dielectric grease in the boot and tip of the spark plug along with using gasket makers on the coil gaskets so water and dirt won't sneak in (especially coil #4)

EDIT:
CaptainXL said:
Dry/clean threads offer the most accurate torque.
I agree.
 

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