Don't use anti-seize on modern spark plugs

[Spud]

I think it's great that you have the "feel" to set bolts with out a torque wrench, but it's not something I would advocate on a forum, even if I thought it could be done reasonably accurately.

Yeah, if the bike is starting to do a pirouette on the center stand (like I'm guessing Squeal's bike's prior owner did when he put in spark plugs) you're probably there and then some.

Reminds me of some ape-fisted morons I watched back in my dirt-biking days crank those tie downs like real men--this bike ain't going nowhere!--and thinking, have fun with those fork seals you dumb-*****!!

 

[RPrice]

I think it's great that you have the "feel" to set bolts with out a torque wrench, but it's not something I would advocate on a forum, even if I thought it could be done reasonably accurately.

Yeah, if the bike is starting to do a pirouette on the center stand (like I'm guessing Squeal's bike's prior owner did when he put in spark plugs) you're probably there and then some.

Reminds me of some ape-fisted morons I watched back in my dirt-biking days crank those tie downs like real men--this bike ain't going nowhere!--and thinking, have fun with those fork seals you dumb-*****!!

Yes, there are many problems related to "ape fisted" applications of torque! My torque wrenches have become my friends, but I must admit that after tightening many a fastener (or plug) to the specified torque I think, "Man, that doesn't seem like it's tight enough??!!". I'd bet some others have felt this way too!

 

[escapefjrtist]

I guess I don't get the whole torque wrench need for spark plugs. The back of the NGK spark plug box clearly shows installation instructions for tapered and gasketed seats. Follow them and you'll get the proper "crush" of the gasket with no worries of damaging the plug (or worse yet, head) due to a bad torque wrench.

Sometimes we complicate things for no reason...Just my $.02

--G

 

[RossKean]

the WORD - from NGK...

Clicky

I have always used a very modest amount of anti-seize on spark plugs but won't in the future. They indicate that the problem is due to over-tightening but I am pretty careful about that. If its not needed, I will stop using it.

 

Ross

 

[hppants]

Ross - your post is compelling. I wonder what Yamaha's take is on the subject? I would think that if there's no residue of anti-seeze on the factory plugs (still on my bike), then that pretty much seals the deal for me.

I'm replacing plugs this weekend - I'm on the fence...

 

[LAF]

Sorry 45 years doing it and no issue, I will continue. It is such a light amount and never seen any issues and they come out when I want them to.

 

[Spud]

Ross - your post is compelling. I wonder what Yamaha's take is on the subject? I would think that if there's no residue of anti-seeze on the factory plugs (still on my bike), then that pretty much seals the deal for me.

I'm replacing plugs this weekend - I'm on the fence...

I have your solution: put it on 2 of the 4. Then you'll know it's at least 1/2 right!

 

[LAF]

Ross - your post is compelling. I wonder what Yamaha's take is on the subject? I would think that if there's no residue of anti-seeze on the factory plugs (still on my bike), then that pretty much seals the deal for me.

I'm replacing plugs this weekend - I'm on the fence...

I have your solution: put it on 2 of the 4. Then you'll know it's at least 1/2 right!

+1

 

[CAJW]

Interesting take on a subject that I'd figured was decided on years ago. I found out the hard way that too much anti-seize was a good way to foul a plug. Ever since I've used it judiciously and have had good results and will continue to do so as we all know about opinions, everybody has one, but some are bigger than others and I ain't fixing what ain't broke regarding maintenance procedures. Regarding torque wrench calibration, in the past I'd bought cheap ones and when they got suspect in accuracy, I'd pitch them. Finally got a nice one and found this procedure to check the accuracy at home for $0.00 and the check is close enough for me. Home torque wrench calibration

 

[C&C]

Maybe more importantly; don't take your plugs out of a hot engine. Extract your plugs from a cool/cold engine (but I do dab a little anti-seeze on mine).

 

[RPrice]

Interesting take on a subject that I'd figured was decided on years ago. I found out the hard way that too much anti-seize was a good way to foul a plug. Ever since I've used it judiciously and have had good results and will continue to do so as we all know about opinions, everybody has one, but some are bigger than others and I ain't fixing what ain't broke regarding maintenance procedures. Regarding torque wrench calibration, in the past I'd bought cheap ones and when they got suspect in accuracy, I'd pitch them. Finally got a nice one and found this procedure to check the accuracy at home for $0.00 and the check is close enough for me. Home torque wrench calibration

Thanks for this information!!

 

[wheatonFJR]

...Finally got a nice one and found this procedure to check the accuracy at home for $0.00 and the check is close enough for me. Home torque wrench calibration

Thanks for this information!!

+1...thanks for sharing that very practical way of checking the calibration.

 

[Fred W]

the WORD - from NGK...

Clicky

I have always used a very modest amount of anti-seize on spark plugs but won't in the future. They indicate that the problem is due to over-tightening but I am pretty careful about that. If its not needed, I will stop using it.

 

Ross

Excellent find!! That is quite clearly the definitive answer. I will be changing my anti seize habits from here on.

Maybe more importantly; don't take your plugs out of a hot engine.

Ummm... why the heck not? That doesn't make any sense to me.

My thinking: The expansion rate of steel (7.3 (10-6 in/in oF)) is less than aluminum (12.3 (10-6 in/in oF)), so if anything the plug should be looser in the threads when warm/hot. Right?

 

[RaYzerman19]

I guess I don't get the whole torque wrench need for spark plugs. The back of the NGK spark plug box clearly shows installation instructions for tapered and gasketed seats. Follow them and you'll get the proper "crush" of the gasket with no worries of damaging the plug (or worse yet, head) due to a bad torque wrench.

Sometimes we complicate things for no reason...Just my $.02

--G

I don't have an NGK box handy, but the proper way I use with plugs with gaskets is to turn in snug by hand, then 1/2 turn more to crush the washer. Any more than that is just crushing the washer more and gaining no torque until you completely crush it, then you don't know where you are...... at that point a torque wrench is recommended IMHO.

Fred, about a hot engine, does a threaded hole does shrink due to heat and get tighter?... but the plug does expand. Also aluminum has a low melting point, and a hot engine might have softer threads than one that's allowed to cool down for a couple of hours...... combustion temperatures are much higher than coolant temperatures... that might be marginal, but why take a chance. Everything was designed at room temperature, yes?

 

[Fred W]

Fred, about a hot engine, does a threaded hole does shrink due to heat and get tighter?... but the plug does expand. Also aluminum has a low melting point, and a hot engine might have softer threads than one that's allowed to cool down for a couple of hours...... combustion temperatures are much higher than coolant temperatures... that might be marginal, but why take a chance. Everything was designed at room temperature, yes?

I didn't think the hole would shrink. It thought that the head would expand, thereby also expanding the hole. No? I'm probably missing something here...

 

[Geezer]

Fred, about a hot engine, does a threaded hole does shrink due to heat and get tighter?... but the plug does expand. Also aluminum has a low melting point, and a hot engine might have softer threads than one that's allowed to cool down for a couple of hours...... combustion temperatures are much higher than coolant temperatures... that might be marginal, but why take a chance. Everything was designed at room temperature, yes?

I didn't think the hole would shrink. It thought that the head would expand, thereby also expanding the hole. No? I'm probably missing something here...

I believe Fred is right. The aluminum head will expand faster than the steel spark plug. As metal expands the hole actually gets bigger. I don't understand the physics behind this, but I know it is true. I have taken a cold engine with a stuck spark plug and warmed it up for a few minutes to loosen the plug and it works. I'm not sure if this will work with a hot engine that has just come in from the road where everything is heated up to the same degree.

I've also seen it done on an iron head where the head was heated with a torch and the plug was iced. I haven't done that myself, but it worked for the guy I was watching.

 

[ionbeam]

...It thought that the head would expand, thereby also expanding the hole...

How do you remove press fit bearings? Heat the housing and the hole that the bearing resides in expands. When the housing (cylinder head) heats the hole gets bigger at the coefficient of expansion defined in engineering tables for various metals and alloys. The housing that is being heated will not have good heat transfer to the bearing, bolt or plug and require a long heat soak before the heat gets to the item that fills the hole.

If you put anti-seize on your spark plugs reduce the torque by 30%-40% to compensate for the lubricated threads.

If the torque setting on your torque wrench falls in the lower 20% or upper 20% of the scale when set for torquing plugs your wrench is not going to be particularly accurate unless it is professional quality. Even then professional torque wrenches are not linear at the ends of the force scale.

Edit: I see Geezer replied while I was typing.

 

[dcarver]

Take a square piece of metal plate, dividing it with a 3-by-3 grid into nine equal smaller squares. Then heat the entire plate. Each of the smaller squares expands.

But if the central square were missing from the start (a hole), then the same expansion would take place in the other 8 squares, leaving a bigger hole. Alternatively, if you heated the entire plate and then removed the central square at the end, after it has expanded, the remaining hole is larger than the original size of a small square.Similar reasoning applies no matter what the shape of the original metal ring is.

From <here>

 

[dcarver]

And fart smellers lay a bead on the inner surface of a bearing to get them easily removed.

 

[Fred W]

Thanks for the confirmation, guys.

With a lot of physics type stuff like this, I usually know how it works, I just don't always know the "why". I guess I should'a paid more attention in school.