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OT: Anti-seize on sparkplugs?

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  • #16
    Originally posted by Horst View Post

    My mechanic said he does not like anti-seize, claiming it does as much harm as good. Being that the plugs now last 100,000 miles (>5 years) he might be right; I have no idea.
    Hey your mechanic does not go by the handle VPT does he? otherwise known as Andy???

    Andy hates anti-seize "oh oh the damn stuff is so messy" yeah that's the point - try not to make a sandwich or anything while using it that's all....

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    • #17
      Honda calls for anti-seize on spark plugs along with being tightened with a torque wrench.

      Time for a new mechanic.

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      • #18
        Originally posted by Seastar View Post
        The expansion of aluminum is greater than steel and causes the head to grip the plug tighter?
        Just a guess.
        Bill
        No.

        Originally posted by RWO View Post
        Makes no sense to me. Alum. expands twice as much as steel for a given temp change. So, there should be more clearance between the plug and the plug hole when everything is hot.

        RWO
        Yes.

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        • #19
          The plug manufacturers are now saying that the plugs come from the factory with an anti-seize coating for use in aluminium heads and to NOT put more on because it interferes.

          Thus, your mechanic is technically right. He's doing what the manufactures of plugs (and likely the auto) are recommending. Now, are the engineers making the recommendation right? I'll let you know in a few years.

          David...

          edit: http://jenniskens.livedsl.nl/Technic...1antisieze.pdf
          Last edited by fixerdave; 12-01-2016, 03:35 PM.
          http://fixerdave.blogspot.com/

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          • #20
            Originally posted by fixerdave View Post
            The plug manufacturers are now saying that the plugs come from the factory with an anti-seize coating for use in aluminium heads and to NOT put more on because it interferes.

            Thus, your mechanic is technically right. He's doing what the manufactures of plugs (and likely the auto) are recommending. Now, are the engineers making the recommendation right? I'll let you know in a few years.


            David...

            edit: http://jenniskens.livedsl.nl/Technic...1antisieze.pdf

            But the plug was stuck. Reminds me of the movie line: "So, there is no evidence. - You mean other than the dead body?"

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            • #21
              Originally posted by Horst View Post
              But the plug was stuck. Reminds me of the movie line: "So, there is no evidence. - You mean other than the dead body?"
              I read the OP as he had a stuck plug, replaced the engine, and NOW the mechanic is recommending no anti-seize. Seems if the mechanic had not used it and the engine then required replacing, it would be an entirely different question.

              I expect, these days, stuck plugs are most likely from cold plugs being torqued into warm engines. Me... I finger-tight them and then wait for the temperatures to balance a little before torquing. But, I'm not being paid by the hour, or job, or anything.

              I've always used anti-seize, except for the last time... but, not really a fair test as it's for a Neon, and the generally accepted practice on those things is to use cheap copper plugs and replace them often. New plugs do seem to make a difference; no idea why when the old ones still look fine. The plugs will only be in for, likely, less than a year so it's not much of a seize test.

              Just bought some plugs for the minivan, where plug changes involve some disassembly to do. That one gets double-platinum, and yeah, I'll probably chicken out and use anti-seize.

              David...
              http://fixerdave.blogspot.com/

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              • #22
                I'd get a new mechanic. What harm does it do? I suppose if you slather it on and get it all over the electrode and into the cylinder maybe.

                Use anti seize and change the plugs often. I change the plugs on my Subarus, and previously VWs, every 60,000 km.

                Anti seize works.

                Also under torquing can lead to stuck plugs as well. Carbon can build up in the threads.
                www.thecogwheel.net

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                • #23
                  i think the verdict is in; anti-seize it is. Thanks to you all.

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                  • #24
                    Originally posted by enginuity View Post

                    Also under torquing can lead to stuck plugs as well. Carbon can build up in the threads.
                    Good addition and yes seen this become a problem many a time esp. with the long reach plugs, make sure you get the initial crunch of the compression washer down when installing plugs for the first time...

                    also another good suggestion is the little 3/8" drive get it gun, if you start to get into a "bind" problem that seems to be getting worse get the small impact gun and set on mild, a little penetrating oil, and then start going for reverse to forward shots, over and over again - you should do nothing but gain more and more clearance till finally you can just keep going in loosening direction and get it out...

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                    • #25
                      Originally posted by tomato coupe View Post
                      Okay, but does anyone know why it increases the chance of thread damage?
                      Pretty much all aluminum blocks and cylinder heads are some type of eutectic or maybe even hypereutectic alloy. I suppose they will not expand as much as the steel spark plug threads. I know it seems counterintuitive since one expects aluminum to expand more, but the alloys used for blocks and heads have a very large silicon content that makes them dimensionally stable over large temperature swings, similar to (but not as good as) cast iron.

                      For that matter, at higher temperature, the yield strength of the aluminum probably decreases... maybe you don't get a significant amount of expansion (being a high silicon alloy) and, at higher temperature, you have softer threads so the problem has only worsened?

                      Guessing a little here - I couldn't find any analysis to backup Ford's claim.
                      Last edited by Fasttrack; 12-01-2016, 04:53 PM.

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                      • #26
                        Originally posted by Fasttrack View Post
                        Pretty much all aluminum blocks and cylinder heads are some type of eutectic or maybe even hypereutectic alloy. I suppose they will not expand as much as the steel spark plug threads. I know it seems counterintuitive since one expects aluminum to expand more, but the alloys used for blocks and heads have a very large silicon content that makes them dimensionally stable over large temperature swings, similar to (but not as good as) cast iron.

                        For that matter, at higher temperature, the yield strength of the aluminum probably decreases... maybe you don't get a significant amount of expansion (being a high silicon alloy) and, at higher temperature, you have softer threads so the problem has only worsened?

                        Guessing a little here - I couldn't find any analysis to backup Ford's claim.
                        This would be my thinking as well, and like you I have not found a definitive technical analysis either. However several factory shop manuals in my possession coincide with Ford's recommendations. It's the procedure I have always followed without failure, and yes sometimes I've followed AK's technique for stubborn plugs but always on a cool engine. I have however seen pulled threads on hot engines, but will admit every case should be judged on it's own particular specifics.

                        Not saying it can't be done otherwise but I believe one's success ratio is much greater by following the advice of the engineers who designed the engine as only they have the insight to make those statements.
                        My only concern with the use of anti-seize is the possibility of over torquing the plug due to the decreased friction between the plug/head thread interface. I usually follow Honda's advice by reducing applied torque by 1/3 of the dry value.

                        From my personal experience I believe a lot of the problems encountered with spark plugs replacement in aluminum heads stems from plugs now lasting 100-150,000kms and more. Two dissimilar metals subjected to those heat and corrosive conditions seen by the spark plug for years on end are going to be problematic. I know folks who haven't changed plugs for more than 15 years. When I get one of those in the shop the first hour is more of an archaeologic dig than a plug change!

                        A couple of quick links below that recommend a cool engine when replacing plugs on engines with aluminum heads.

                        https://www.pepboys.com/car_care_cor...l_and_removal/

                        Another issue is thread galling in aluminum cylinder heads. Galling or binding between the plug and head can destroy the thread and possibly result in plug breakage. To avoid this, it is important to let the engine cool down before trying to remove a spark plug.
                        http://www.pelicanparts.com/BMW/tech...park-Plugs.htm

                        Begin by prepping the car. The only thing that you really need to do is to make sure that the car is cold. If you try to remove or install spark plugs in a hot car, then you may encounter problems with the spark plugs gumming up or damaging the relatively delicate threads in the aluminum cylinder head. Just make sure that the car is cold, or at the bare minimum, only slightly warm to the touch.
                        Home, down in the valley behind the Red Angus
                        Bad Decisions Make Good Stories​

                        Location: British Columbia

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                        • #27
                          There's also the possibility that the guy writing the Ford guidelines didn't understand it completely as well. I could well imagine that the original rule was to never service spark plugs on warm engines (because then you'll screw the new one in while it's still warm and strip it in a few months down the road). To my knowledge, and that of our metallurgists, there are no aluminium alloys with a smaller thermal coefficient than steel.

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                          • #28
                            The old air cooled volkwagons were the worst - if one came in that we did not maintain it was a real crap shoot and keep your fingers crossed for good removals,
                            many a heli-coil installed on them - and they were only short reach plugs - good for not having as many threads to give trouble but bad for torque pressures on the threads - their heads were very soft too

                            Different plugs have different plating too - I like NGK's they seem to remove better than most in fact have been going into aluminum motorcycle heads well before most cars ever ran aluminum heads...

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                            • #29
                              When I raced Moto-Cross in the early 70s, NGK was said to be "No Good Kind". They didn't last long in a 2 stroke engine. I always got the best life out of AC plugs. I suspect they have all improved a lot since then.

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                              • #30
                                Originally posted by fixerdave View Post
                                The plug manufacturers are now saying that the plugs come from the factory with an anti-seize coating for use in aluminium heads and to NOT put more on because it interferes.
                                My mechanic leaves his tech magazines in the waiting room which I find much more interesting than the rest of the stack. There was an article, written by a person getting his info from the spark plug manufacturers for an audience of auto shop owners and mechanics, that says exactly that. The plugs NOW are made with coatings on the threads that do not have the problem with aluminum heads as in days past and anti-seize paste is unneeded. The problem mentioned was when too much paste is applied and it gets into the cylinder.

                                FWIW.

                                Steve

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