Plugs anti-seize or not

I just love it when 2 gurus differ,one says never and the other says always use anti-seize on plugs w/reduced torque.I intend to us it anyway. Any thoughts. Gurus yea,yea!!!

I always use it, and tighten them enough to crush the washer.

Gurus--what a joke.

The folks that make spark plugs and the folks that make engines say no antiseize.

I've never had any issues with plugs sticking in cylinder threads as long as they were properly installed to begin with. Maybe I've just been lucky? No antiseize for me on sparkplugs, though I ALWAYS use it on the exhaust port threads.

In 45 years of doing my own vehicle maint, I've never used the stuff.

I trust Oak

Oak says NEVER use on plugs. Tom Cutter I think advise against it too.

Well, in the BMW manual it says to use graphite grease. Personally I apply a very light coat when changing plugs, but that's about it

Some reading for your consideration.

http://mechanicsupport.blogspot.com/2010/10/spark-plug-anti-seize.html
http://www.avweb.com/news/maint/spark_plugs_198595-1.html
http://www.aircraftspruce.com/catalog/eppages/antiseize.php

That said, the newer plugs seem to be coated with a material that makes it no longer needed.

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

I may stop using it since I now use NGK plugs in my bike.

I look at anti-seize similar to peanut-butter - perhaps because of the similar consistency. Some places really need it, but it probably wont hurt putting a thin coat on most any metal threads. Granted, it is messy and unnecessary but generally won't damage the threads or cause other problems - unless it is used around brakes or other grease-free areas. Some uses, like aluminum to aluminum threads on the exhaust nuts require anti-seize.

Some industries (i.e. nuclear) put anti-seize on nearly all fasteners, but it is really needed on materials which tend to gall in contact such as stainless and aluminum. I have used anti-seize on spark plug threads a few times: it is messy and has no benefit but has never caused any problems.

In servicing Euro alloy heads for many years, the problems I have seen always have to do with, "if some is good, more is better and too much is just enough". It turns into bubble gum consistancy and has to be removed with a thread chaser. If you can't just loosen the plug and turn it out with fingers, it's a problem.

I use just two drops of light machine oil. No worries.

Some is good, more is better, too much is just about right - Jerry Lee Lewis

Understanding is everything. A little smear of anti-seize in and of itself does no harm. But it reduces the measured tightening torque by from 25% to maybe 40% because the friction component of the torque resistance is reduced. What the wrench senses is a combination of friction and clamping force. So if anti-seize has been used and a person sets a torque wrench to the specified torque the resulting clamping force may exceed the thread strength and the threads will strip.

If anti-seize has previously been used some remains. Then if new plugs are installed by a person who doesn't know it was there - the threads may strip. That is the downside.

On low miles-per-year bikes if the plugs remain undisturbed for several years, or if the engine overheats even a little the plugs may stick in place and the threads may tear upon removal of the plugs. Anti-seize will prevent this. That is the upside.

So you get to take your pick of which risk you are willing to take.

Paul,

Are plugs a torqued install on Airheads? I know on most automotive installations, they are a turned value, like 1/16 rotation or such depending on the seat type.

When building a few auto engines, most torqued fasteners have values given using either a moly paste (ARP fasteners, ARP paste), or engine oil, with different values for the same fastener depending on which is used. I know on my Hexhead, the wheels are a dry install, with torque based on that.

I like a small shmear of anti-sieze on my plugs, I've had plugs pull threads out of aluminum before, when not using it, so I do now.

44 years of riding motorcycles
445,000 miles on my 1977 R100RS in 26 years
I always use a dab of anit-seize on my plugs

I Have never stripped a plug
I have never used a torque wrench on plugs

Common sence has to be used when installing plugs!

I'm with you on this one. I work in Aviation and we use a small dab of anti-seize on all ignitors/spark plugs. Never stripped a plug hole. Ever. Just sayin. We do torque the ignitors, but that is taken into account by the manufacturer. I don't torque my spark plugs on my 78 R100RS. Had it since 86. Once again, it works for me so it's in the world of opinions and experience.

DARRYL CAINEY said:

44 years of riding motorcycles
445,000 miles on my 1977 R100RS in 26 years
I always use a dab of anit-seize on my plugs

I Have never stripped a plug
I have never used a torque wrench on plugs

Common sence has to be used when installing plugs!

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Just did my valves yesterday and noticed that the plugs seemed a bit more resistant to coming out; once broken loose they didn't want to back out by fingers. I used anti-seize on them for the first time when I installed them new.

I used a very very light dab of Loctite Nuclear Grade Nickel Anti-Seize on them again when I re-installed them; they spun right in. We use this stuff at Diablo Canyon NNP; it's rated to 2400??F, and is spec'd for the assembly of dissimilar metal components.

At 2400??F I know it isn't hardening up on the threads but I'm now a bit leery about using it at all. I'll see how it goes the next time I pull them.

JStrube said:

Paul,

Are plugs a torqued install on Airheads?

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Yes. BMW provides a torque spec. Some professional techs use it. Some owners use it. Some don't. I don't have the specs for Airheads handy but BMW says 25 NEWTON METERS for the R1150R, and 20 NM for the F650GS, thread condition clean and dry.

As I noted in the earlier post, if you use the spec and ignore the fact or don't know there is lubricant on the threads you will apply excess clamping force and can pull threads.

With new plugs with new crush washers it is easy to feel the washer crushing. But if plugs have been removed and the same washer is re-used, you can't feel much of anything except loose - seems tight. This is a danger point for using just feel. The same applies to drain and fill plugs with re-used crush washers, by the way.

Thanks everyone,good replys,I'll use it lightly and a torque wrench w/redused torque as recomended.When I got this bike,1983 R100,18K the plugs were in scary tight,don't want that again.

My technique with spark plugs in aluminum heads is to slightly under tighten the plug. After stripping out a plug or two in aluminum heads and the ensuing grief that follows, one becomes more observant of - what is important - and what is nice to have. Slightly under tightening is preferred to over tightening.

I frequently ignore the manufacturers spark plug torque recommendations for aluminum heads. The reason is based on past experience and problems from following manufacturers recommended spark plug torque. For 14mm plugs - which is about all I use - I never use a torque wrench, but can fairly accurately estimate the installation torque between 8 and 15 ft-lb (11 to 20 N-m). The reason to torque a spark plug is to prevent loosening.

Over tightening plugs has caused me many problems and significant grief. Under tightening, in contrast, has never caused or been the cause of any problems. I have even found plugs slightly more than finger tight with no abnormal wear and in excellent condition during routine maintenance. However, the plugs must be more than finger tight.

It seems the issue with anti-seize or lubricant on the threads is the change in torque numbers associated with the lubricant. As such, another excellent technique is to tighten the plug 1/4 - 1/2 turn after finger tight or 1/8 turn after flattening the crush washer. Also, (to point out the obvious) anti-seize will not fix any threads or repair damage from an over-tightened plug.

Stan_R80/7 said:

It seems the issue with anti-seize or lubricant on the threads is the change in torque numbers associated with the lubricant. As such, another excellent technique is to tighten the plug 1/4 - 1/2 turn after finger tight or 1/8 turn after flattening the crush washer. Also, (to point out the obvious) anti-seize will not fix any threads or repair damage from an over-tightened plug.

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I think you hit it right on the head. Since plug and engine manufacturers cannot control how users are going to apply antiseize, and subsequently torque, the only logical answer in an litigous society which abhors personal responsibility, is to entirely forbid antiseize use. Logical for them and their legal team, but not necessarily best practice for ourselves. Just have to be aware of torque issue.