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Spark Plug Thread Lubrication?

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Re: Spark Plug Thread Lubrication?

Postby JohnnyB » Thu Jun 17, 2010 8:40 pm

rally wrote:I would never use anti-seize on spark plugs period and on Aluminum heads to boot. I talked to an Autolite spark plug tech person and he told me dont use it, it causes fouling, misfire, etc. I run Aluminum heads on my drag motor. The only way i pull any plugs out is when the engine is cold, the next day. I never remove plugs to look for correct jetting, i jet for best MPH. I have removed plug #1 for TDC after a pass but will not do it only if i really have to. Save the heads and threads, remove only when cooled down or next day.

You are running a motor that gets the plugs pulled frequently on a regular basis. And you pull em cold... I'm talking about your typical car that folks put plugs into aluminum heads and leave em for 50 to 100 thousand miles and never pull em. Do that bare, and when your mechanic pulls em ( hot ) after 3 or 4 years, there is a very good chance that he will get more than the spark plug to come out. Those guys dont wait for a motor to cool, they get paid by the book, or by the hour and don't care. If they get to sell you rebuilt heads, all the more work for them. What ever works for you is great, I just find a SMALL AMOUNT, properly placed works good. And the plug won't misfire if its only on the threads, and just a dab. The ground will still be fine thru the seat where the lube isn't. It can't foul the motor if its a very small amount, and not past the first or second thread as it wont ever get into the motor. it will be trapped in the threads. If ya goober it up like a wheel bearing, thats a different story.
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Re: Spark Plug Thread Lubrication?

Postby af2 » Thu Jun 17, 2010 8:49 pm

MadBill wrote:
rally wrote:I would never use anti-seize on spark plugs period and on Aluminum heads to boot. I talked to an Autolite spark plug tech person and he told me dont use it, it causes fouling, misfire, etc. I run Aluminum heads on my drag motor. The only way i pull any plugs out is when the engine is cold, the next day. I never remove plugs to look for correct jetting, i jet for best MPH. I have removed plug #1 for TDC after a pass but will not do it only if i really have to. Save the heads and threads, remove only when cooled down or next day.


The Autolite guy's position sounds like the cautious outlook of someone more concerned with being slagged for manufacturing a 'defective' plug than of someone interested in the long term viability of the engine. Applied sparingly anti-seize is all good.



Yep and also Bill's next quote as in finger tight BS.
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Re: Spark Plug Thread Lubrication?

Postby Craigm » Thu Jun 17, 2010 9:05 pm

How tight is recommended? I can get a torque wrench on 7 of 8 plugs and typically put them in at 15 ft-lbs in aluminum heads. What do others do?
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Re: Spark Plug Thread Lubrication?

Postby rally » Thu Jun 17, 2010 9:17 pm

Sorry never would and will not use anti-seize period. Its a fact the stuff causes problems. You want to keep the threads from being pulled out and stripped, take them out when the engine cold, race or factory engine.
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Re: Spark Plug Thread Lubrication?

Postby JohnnyB » Thu Jun 17, 2010 9:47 pm

Craigm wrote:How tight is recommended? I can get a torque wrench on 7 of 8 plugs and typically put them in at 15 ft-lbs in aluminum heads. What do others do?

Cant really say. It all depends on the threads and size of the plug hole. Plugs are like anything else, each size has a proper torque. However, I do know that if you over torque a plug, the steel plug will never distort before the aluminum threads. The big problem is alls it takes is one time over torquing a plug and the hole is on its way to being ruined. If you over torque the plug, the second you exceed the aluminum's ability to stay put, the pitch of the threads will change. It happens a lot easier on a hot thread than cold. The minute you change the pitch of the thread you are screwed. You either re-tap the hole and hope the pitch comes back without too much metal loss, or every time you install or REMOVE a plug from that hole you are slowly screwing up the threads. The only end result will be phucked up threads. Happens at work all the time, big brute guy overtorques stainless screws in aluminum lugs for electrical copper wire terminals for motors. (electrical ). They back off, remove the wire, and the screw still goes in and out but 'hard', even without any wire under it. Big lug guy doesn't understand, and blames it on everything but... over torque, changed the pitch of the aluminum threads, but not the screw ( or metal plug on a car motor). Now everytime you run something in the hole you are wasting the threads. It is compounded on a spark plug due to galvanic corrosion. Aluminum and steel with electrical current will cause it (ALL THE TIME) even without electrical current from the ignition, moisture in the slightest amount will cause it. You either break the corrosive bond with frequent removal of the plug, or you put something on the metal to prevent the corrosion. One of the two, your choice. If you dont, the metals will eventually corrode, and become one. Then yo' be phucked. If you over torque the threads one time to the point of changing the pitch of the aluminum you are just screwed again, a different road to the same destination - pulled threads. So, what torque? Find the correct torque for the fastener size and DO NOT exceed it, ever, not even once. Google 'galvanic corrosion' it will scare you. I learned it in electronics school back in the seventies.
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Re: Spark Plug Thread Lubrication?

Postby C Stevens » Thu Jun 17, 2010 10:00 pm

Well then, obviously, all the top fuel and top alcohol racers are doing it wrong. :shock:
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Re: Spark Plug Thread Lubrication?

Postby JohnnyB » Thu Jun 17, 2010 10:13 pm

C Stevens wrote:Well then, obviously, all the top fuel and top alcohol racers are doing it wrong. :shock:

Apples and oranges- they pull the plugs ALL the time. The only way anti-seize causes misfires is when you are so clumsy you get it on the center tip or porcelin. Then it will cause carbon tracking and , Yes a misfire. If you cant do it without getting it on the plug tip, pay somebody that can. Top fuel guys burn the sheeeiit out of half the plugs on every run and toss em. Top fuel guys burn the sheeiit outa most anything that is near the cylinder, let alone in it....Top fuel guys have spare heads and engines in their trailers, do you? :)
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Re: Spark Plug Thread Lubrication?

Postby Alan Roehrich » Thu Jun 17, 2010 10:36 pm

Years ago, I attended a performance and driveability seminar hosted by Delco. Their testing showed that on average, even the correct application of anti-seize on spark plug threads increased the heat range of the plug by two numbers, and could cause detonation and/or retarded timing (in the case of computer controlled ignition timing). Delco went so far as to put a coating on the threads of any spark plug they had designed to be used in an aluminum head, so that anti-seize wasn't necessary. There were several tech bulletins issued, one of which dealt with the need for techs to wash their hands after handling those plugs to prevent coating related illness.

I usually use a drop or two of good motor oil. This being a BBS called "speed talk", most people would be thinking of performance engines when reading a post here, and wouldn't be likely to think anyone was asking about an application where the spark plug would be left in for 100K miles or 10 years.
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Re: Spark Plug Thread Lubrication?

Postby Warp Speed » Fri Jun 18, 2010 7:21 am

We use Coposlip high temp anti-sieze on the threads of all of our spark plugs. We have done extensive testing with Bosch on this, and this is about the only lube that provides the best grounding and temp transfer, while still providing the needed lubrication to get them out without damage. You do need to keep it off of the exposed chamber area as it can cause a misfire/detonation as mentioned by others, but as far as changing the heat range, it has shown VERY little to no effect. The metal particles in the lube help ensure the needed grounding (this is one of the most important grounds in the entire system) just don't get carried away with the amount to avoid chamber contamination!

We used to use EPL, engine oil ect. on the threads, but again, after testing different lubes, found the anti-sieze to be the best.

This testing all came about during the early 2000's. AC Delco was pulling back their motorsport efforts, and due to this, they started having some quality control issue's with their plugs. We started breaking pieces out of the intake valves on high duty cycle tracks (Michigan, Chicago ect), and after chasing just about everything in the book, we found the plug threads to be undersize from the sae spec. This was having a huge impact on heat transfer, and effectivly raising the heat range of the plug into the danger zone for our extended full throttle applications. This is what started all the plug and lube testing, and it is something we continue to monitor constantly.

Proper torque is VERY critical also, as thread engagement (as stated above) has a huge effect on the plugs ability to cool. Most plugs need to be torqued 15-18ft/lb, but can vary slightly with manufacture. Plugs with a compressible sealing washer should be installed, torqued, loosened and re-torqued to pre-compress the washer, thus ensuring the proper thread engagment and heat transfer during operation.

Just my 2 cents!
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Re: Spark Plug Thread Lubrication?

Postby razor66 » Fri Jun 18, 2010 7:46 am

Alan Roehrich wrote:Years ago, I attended a performance and driveability seminar hosted by Delco. Their testing showed that on average, even the correct application of anti-seize on spark plug threads increased the heat range of the plug by two numbers, and could cause detonation and/or retarded timing (in the case of computer controlled ignition timing). Delco went so far as to put a coating on the threads of any spark plug they had designed to be used in an aluminum head, so that anti-seize wasn't necessary. There were several tech bulletins issued, one of which dealt with the need for techs to wash their hands after handling those plugs to prevent coating related illness.

I usually use a drop or two of good motor oil. This being a BBS called "speed talk", most people would be thinking of performance engines when reading a post here, and wouldn't be likely to think anyone was asking about an application where the spark plug would be left in for 100K miles or 10 years.


I am the OP of this topic and the application that I was personally referring to with this question is street driven somewhere between 3,0000 and 5,0000 miles per year along with some open tracking road course events as well as a couple of autocross events thrown in. My plugs are extremely difficult to access for replacement, so unless I have an issue that is or that I think could be related to the plugs then I usually only change then perhaps every couple of years or so.

As with a lot of things it looks like there are multiple methods of which have their own pros & cons and perhaps no clear cut best practice for all applications. With all the information so far, I think for my particular application I would be inclined to continue to use a small amount of carefully placed anti-seize on the threads as a conservative approach to not having issues with the threads in the heads. I have seen where Champion Aerospace makes a spark thread lubricant (no. 2612) containing graphite that they recommend using, but it might just be for use in aviation turbine engines. I am definitely open to further suggestions and input as I do want to utilize the method that will best prevent all related issues from a mechanical and performance standpoint. Thanks for all the input so far.
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Re: Spark Plug Thread Lubrication?

Postby cjperformance » Fri Jun 18, 2010 8:03 am

Plain old Castrol , or other brand, LMM , Moly grease. Wiped sparingly on the thread. You will easily get the plugs out of iron or alloy heads when hot or cold with no problem. Wont matter if they have been in there for 5min or
90,000km as in many factory vehicles. Even Ford 3valve V8's which some tend to find problematic.
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Re: Spark Plug Thread Lubrication?

Postby JoePorting » Tue Jul 20, 2010 2:43 am

Interesting thread. I alway use two drops of regular 20/50 motor oil on the threads and one drop on the washer. I've been doing that for 30 years and never had a problem. I pulled plugs out of my own car after 100,000 miles and noted the oil was still there. I think most problems stem from people cross threading the plugs, or raming the plug in with a socket without first engaging the threads. I find that it is VERY important to first thread the spark plug in by hand to make sure you are not cross threading it, and then torque it down to about 15 pounds as mentioned. If the plug won't go in or stops after half a turn, back it off and try again. With all the different angles involved, screwing in a spark plug is alot more difficult then people will admit. I like to replace one plug at a time so that I can look at the one's already installed to get the angle right.
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Re: Spark Plug Thread Lubrication?

Postby SWR » Tue Jul 20, 2010 3:33 am

Hmm. If anti-seize raises the heat value by 2, then the NGK 9's that fouled last time (8's worked) should run all nice if I have anti-seize on them according to this statement. Guess it's test time... :wink:
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Re: Spark Plug Thread Lubrication?

Postby RW TECH » Tue Jul 20, 2010 5:36 am

Warp Speed wrote:We use Coposlip high temp anti-sieze on the threads of all of our spark plugs. We have done extensive testing with Bosch on this, and this is about the only lube that provides the best grounding and temp transfer, while still providing the needed lubrication to get them out without damage. You do need to keep it off of the exposed chamber area as it can cause a misfire/detonation as mentioned by others, but as far as changing the heat range, it has shown VERY little to no effect. The metal particles in the lube help ensure the needed grounding (this is one of the most important grounds in the entire system) just don't get carried away with the amount to avoid chamber contamination!

We used to use EPL, engine oil ect. on the threads, but again, after testing different lubes, found the anti-sieze to be the best.

This testing all came about during the early 2000's. AC Delco was pulling back their motorsport efforts, and due to this, they started having some quality control issue's with their plugs. We started breaking pieces out of the intake valves on high duty cycle tracks (Michigan, Chicago ect), and after chasing just about everything in the book, we found the plug threads to be undersize from the sae spec. This was having a huge impact on heat transfer, and effectivly raising the heat range of the plug into the danger zone for our extended full throttle applications. This is what started all the plug and lube testing, and it is something we continue to monitor constantly.

Proper torque is VERY critical also, as thread engagement (as stated above) has a huge effect on the plugs ability to cool. Most plugs need to be torqued 15-18ft/lb, but can vary slightly with manufacture. Plugs with a compressible sealing washer should be installed, torqued, loosened and re-torqued to pre-compress the washer, thus ensuring the proper thread engagment and heat transfer during operation.

Just my 2 cents!


x2.

I use copper anti-seize with none on the first few threads that protrude into the chamber and always torque the plugs to 20 ft. lbs. after crushing-in the washer.

I picked copper specifically for thermal conductivity & have had no issues with it but I'm going to get some Copaslip & use it. No reason not to at this point since actual validation testing has been done with it to prove its effectiveness.

Thanks for the tip. :)
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Re: Spark Plug Thread Lubrication?

Postby benno318 » Tue Jul 20, 2010 6:32 am

as a mechanic, i have changed thousands of plugs and have noticed a few things over the years. the platinum plugs, as fitted to many toyota's now, are in for 150,000km. i recently serviced one that was overdue, at 180,000km - and yet they were EASY to remove!! i think correct tension from the factory had a lot to do with that. all too common that most dealer type mechanics have no clue and go WAY too tight.

i think too, another problem that can make plugs hard to remove is when people actually do not tighten enough. it seems that carbon tracks up the threads in this case, can be seen clearly after the plug is removed, and felt all the way out!!

in alloy heads, some plugs seem to be easier to remove than others, ngk's i found are pretty good - champions, not so... different coatings applied to the threads is my guess there.
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