Anti-seize on spark plug threads?

[folkenheath]

In my app when I used equations to calculate torque, you use a friction coefficient, and it ranges from .12 - .3 at the defaults depending on lubrication type, finish, plating, etc. Anti-seize is the lowest one at .12, dry raw non plated bolts is up to .30(who uses those?). These are from Mechanical Engineering Textbooks and the Machinery's Handbook. For example, for a dry Grade 8 zinc plated 1/2-20 thread I calculate 120 lb-ft at 75% of proof. With oil lubricant its 108, with cadmium plating its 96, and with antiseize it calls for only 72 lb-ft.

Of course do not use those values when there is a gasket or seal, etc. This assumes a metal to metal clamp and of course if there is an application specific spec use it, I am just putting this out there so show you how much it can vary, because the friction takes up too much of the torque and less goes into actually tensioning the fastener. Many race engine builders torque rod bolts by stretch instead of torque, because it eliminates the friction of the torque and just uses actual bolt stretch, which is directly related to tension and therefore stress/strain.

Spark plugs don't need much at all, you are just trying to seal the taper seat or gasket is all. I just cinch them up by hand. I don't normally torque anything but main bolts, rod bolts, head bolts, ring gear bolts, and valve body bolts. Pretty much everything else in a car/truck I go by feel, although I'm sure I forgot something.

 

[Lolz_cats]

I feel like an idiot. I’ve made it halfway through changing the plugs, but can’t get the new one I’m working to thread in. I haven’t put any pressure in it. Just have the spark plug in a spark plug socket with not wrench attached. Any tricks for these kind of scenarios? All of the others have gone in fine so far doing this

One trick that you can do is grab a piece of rigid vacuum line or rubber hose and slip it over the electrode on your plug. Then use the the hose as an extension to reach into the plug hole and get the threads started. I find that the rubber hose gives you much better feedback than a socket and extension when positioning the plug without seeing it. It especially helps when you can't get your fingers in there.

 

[Wes Harden]

Only time I ever use a lubricant on wheel lug studs, is the inner bud nut only, not the lug nuts. Always dry. I might change my tune if I had to deal with salted winter roads. I truly use very little antisize. the copper kind on my g22.

 

[bigblock454]

I put just a skim of anti seize on all plugs in all of my engines, car/truck/lawn mower/chainsaw everything. I also lightly oil (any oil but it's usually Rotella-T cause that's what i've got lots of) all lug threads, however just the threads, not the beveled portion of an acorn nut that mates with the rim, that part stays dry.

 

[centexk5]

I anti-seize everything. Hubs, ball joints, tie rods, brake caliper brackets, brake calipers, spark plugs, back of the wheel where it meets the hub, etc. I hate fighting breaking parts free because they rusted together.

 

[76zimmer]

Rust in TX?

 

[centexk5]

Well, surface rust.

 

[diesel4me]

I anti-seize everything. Hubs, ball joints, tie rods, brake caliper brackets, brake calipers, spark plugs, back of the wheel where it meets the hub, etc. I hate fighting breaking parts free because they rusted together.

My methods exactly..however,it seems I never have to ever take apart anything once I busted my ass for hours using torches and hammers to get parts separated after they got welded together with rust & road salt for 20+ years...all I did was make it easier for the next owner,or parts scavenger at the junkyard....

One exception is exhaust studs..I can put a whole can of never-seize on those,and they are almost guaranteed to snap off anyways a few years later when new pipes need to be installed..

 

[Blue85]

Torque specs are for fasteners in like new condition. On 40 year old wheel studs there is sure to be some putting on the threads even if you wire wheel them and run a tap through the nut. You could measure the drag with a dial torque wrench, but I suspect the drag is more significant when the threads are "under load" as you tighten them.

 

[folkenheath]

Good point Luke, ARP has done a lot of research on that subject, torque vs stretch and the number of cycles that a fastener has been torqued. You can see in the ARP chart that the bolt threads kind of lap themselves in with cycles.

Now if some threads are ever galled, corroded, or damaged it will have the opposite effect and you may not reach proper preload in that case without ruining the threads more, this is when the fastener should be replaced.

This is why some say to torque a new rod bolt a few times before you continue with the engine assembly. With their ARP lube, the got more consistent results. But you will notice they specify a lower torque in their instructions with the ARP lube.

Here is more info on that from ARP...(click on the "installation" tab in the middle of the page)

https://arp-bolts.com/p/technical.php

 

[mrgoodwrench]

Im a mechanic by trade and have used anti sieze on every plug i have ever installed hundreds of them in steel and aluminum heads never had a problem do not get it anywhere but the threds. As far as torque ive never torqued to spec ive always done by feel. There are many opinions some would say no anti sieze and always torque to spec well ive done many and never had an issue.

 

[mrk5]

I use a torque wrench specifically because I don't do it for a living. I might install spark plugs once every 2 or 3 years. I have no feel for the tightness of fasteners; my arms are far out of calibration. I know from my little bit of experience I will over tighten and sometimes break bolts so then I err on the too light side.

I wouldn't be terribly wound up about not having a torque wrench for spark plugs, but other things like intake manifolds and wheels I like to torque to spec to ensure the bolt tightness is even across the part.

 

[6.2Blazer]

I've always installed anti-seize on spark plugs, just a small amount on the threads and often take a shop towel and wipe any excess off. I think the issue is people putting way too much on the plugs and it globs up around the electrode. Also have always used it on the wheel studs on all vehicles....from my K5 on 40's, wife's minivan, SxS, lawnmowers, and multiple other vehicles. Never had a problem after 20+ years and probably hundreds of times putting on tires and wheels.

 

[campfire]

Given that the torque specs I've found are generally at the extreme end of the rating for that diameter fastener, there probably is very little fudge factor to deal with.

Heck, how many really even use a torque wrench on lug studs? It's not real tough to reach 75ft-lbs, which is the 7/16 lug stud spec IIRC, and if not using a torque wrench, I'd be willing to bet more often than not, they are technically "over-torqued" even by those not using anti-seize. And yet live. Lol.

As a counterpoint, I have inadvertently wallered out the lug holes on a couple sets of steel wheels. And the antiseize makes the nut more likely to vibrate loose, so I don't feel great about lowering the torque spec.

For these reasons I no longer use antiseize on my lug studs. P.B. Blaster keeps the corrosion away without adding nearly so much lubricity.

 

[anwat]

I use anti-sieze, the silver stuff, and yes, it seems to get places you don't put it somehow. I also use the dielectric grease in the boots, and an actual torque wrench on my plugs. My gasketed plugs are supposed to be tightened to 15-22 ft. lbs. per Edelbrock, and tapered plugs go to 15-20 ft. lbs. Last time I changed my plugs, the boots all slid off pretty easy, and the plugs came out without an issue, even #4 and #8. It was worth the extra work to not have to fight when it came time to take them out.

 

[mrgoodwrench]

Agreed anti-sieze and di electric grease the way to go and nothing wrong with tq wrench i dont use one for plugs but thats just because i have done so many that i have a feel for it and dont need it anymore.

 

[mrk5]

Living in semi-arid Colorado, I never worried much about anti-sieze, but all the shit they spray on the road when it snows these days has me using it more often.

 

[JoshHefnerX]

My canam came w/ anti seize on the plugs from the factory. Infact a few got a bit messy and got some on the electrodes and have caused no-fire situations.