Spark plugs and Anti-seize

[Spooling]

I recently came across this tech bulletin from NGK and thought I'd share it. Not sure if anyone else had seen it.

They basically say to not use anti-seize on their spark plugs which have the metal coating, as you risk over tightening the plugs.

https://www.ngkplugpro.ca/content/contentfiles/pdf/NGKSP-0907-1R-Anti-SeizeonSparkPlugs.pdf

 

[Cambo]

This is a marine environment close to 20 years on salt water my plugs come out nice and smooth . I use copper anti-seize

you don't want this to happen

 

[Zizzou 192]

My Service Manual says to torque the plugs in at 18.4 ft / lbs (2015 sx192 SHO).

.So yes I break out the digital torque wrench for that as silly as that sounds. That is such a low value it is outside alot of torque wrenches' lower range.

However, the manual does not say anything about using aluminum anti seize or iridium plugs, but I chose to use both due to issues discussed in this forum.

I believe the top end of the 1.8's are aluminum so I chose the aluminum anti seize. No issues using this currently.

 

[Zizzou 192]

Any reason to use the copper anti seize over the nickel or aluminum?

I have no idea what alloy the plugs are made of. I am guessing Unobtanium.

 

[Cambo]

It’s rated for high temperature

 

[swatski]

I recently came across this tech bulletin from NGK and thought I'd share it. Not sure if anyone else had seen it.

They basically say to not use anti-seize on their spark plugs which have the metal coating, as you risk over tightening the plugs.

https://www.ngkplugpro.ca/content/contentfiles/pdf/NGKSP-0907-1R-Anti-SeizeonSparkPlugs.pdf

New-er plugs do not require anti-seize.
Especially if changed regularly.
Also - it can throw off heat transfer.
Finger tighten, then about 1/2 turn with a spark plug wrench.

I would not use a torque wrench if using anti-seize.

--

 

[njmr2fan]

Weird... Just changed spark plugs in my Ford Edge Sport and my buddy who was helping stopped me and gave me a quick lesson. Said if the bottom of the plug is shiny bright metal (like the Motorcraft plugs I had) don't use anti-seize. As was mentioned, it can increase heat and cook the plug, and it will increase torque values because you'll wrench the plug in harder than spec'd. Dark grey and non shiny metal plugs still get anti-seize.

 

[Stevenpigsooie]

No expert but I don’t use anti-seize since NGK says not to for the reasons listed above.

 

[Cambo]

I'm not sure if NGK changed the coating on the spark plugs from the older style 4 stroke MR1 motors but there were many posted issues with the plugs seizing and snapping in the head . The three posts above probably never boat in salt water but for those who do I highly recommend anti seize . With 12 seasons of changing plugs and having no issues not even a fouled plug, that was also an issue with those motors. Heat transfer may be an issue with a passenger vehicle but these are raw water cooled.

In the videos below you can see what happens in a marine environment

look at minute 2:30

 

[Zizzou 192]

Under my shade tree knowledge of metalurgy and mechanical engineering, seating a spark plug works something like this:

When the spark plug is torqued to the intended value, it compresses the "lock compression washer" and then the threads of the plug bond to the head in a kind of cold weld in a vacuum when heat and pressure is applied.

The term used to describe this phenomenon is known as galling. The degree that this chemical reaction occurs determines how hard the plug is stuck in the threads in the head. I assume Yamaha and NGK have a very specific theoretical amount of how much this should occur.

Unfortunately this phenomenon increases with heat and pressure. As these engines need to be run in the top 20% of their rpm range just to get the boat up on plane, spark plug life is really short moving down to avation levels of about 100 hours.

If boat dealers are charging $500 for oil plugs and filter change I have no intention on finding out how much they charge to drill out a seized plug and insert a heli-coil.

anyways... this avation forum thread has a great bit on the types of anti seize, how to apply, Bosch, NGK, and Champion guidance, the choice if to apply or not, and the inportance of the torque value...

http://forums.pelicanparts.com/porsche-911-technical-forum/475238-anti-seize-spark-plugs.html

Keep in mind that they are talking avation where the stakes are a litte higher than our 300 hp bar slash swim platforms.

 

[swatski]

I'm not sure if NGK changed the coating on the spark plugs from the older style 4 stroke MR1 motors but there were many posted issues with the plugs seizing and snapping in the head . The three posts above probably never boat in salt water but for those who do I highly recommend anti seize . With 12 seasons of changing plugs and having no issues not even a fouled plug, that was also an issue with those motors. Heat transfer may be an issue with a passenger vehicle but these are raw water cooled.

In the videos below you can see what happens in a marine environment

look at minute 2:30

That is true about marine environment but a coating of spray lubricant/silicon or, better yet - CRC 656, inside the plug rubber boot and coil will keep moisture and salt away from plug threads with regular changes.

Either way, it works, some here with most hours use anti-seize, like jeff Cobra. The one thing I would NOT do is to use torque wrench when using lubricant/anti-seize on the plug threads.

--

 

[Gym]

That is true about marine environment but a coating of spray lubricant/silicon or, better yet - CRC 656, inside the plug rubber boot and coil will keep moisture and salt away from plug threads with regular changes.

Either way, it works, some here with most hours use anti-seize, like jeff Cobra. The one thing I would NOT do is to use torque wrench when using lubricant/anti-seize on the plug threads.

--

Unfortunately it's not the top part of the plug that rusts. It's the threads. The theory is that #3 valves often stay open on shutdown allowing moisture to contact the plug threads. I don't know if this theory holds any water or not but it's almost always #3 that rusts and breaks. I'm sure crc would burn off if applied to the threads so that's why we use antiseize.

 

[Zizzou 192]

Yes. Great source of galvanic corrosion as well. Two different metals meet and just add water. Rusty Jones!

 

[swatski]

Under my shade tree knowledge of metalurgy and mechanical engineering, seating a spark plug works something like this:

When the spark plug is torqued to the intended value, it compresses the "lock compression washer" and then the threads of the plug bond to the head in a kind of cold weld in a vacuum when heat and pressure is applied.

The term used to describe this phenomenon is known as galling. The degree that this chemical reaction occurs determines how hard the plug is stuck in the threads in the head. I assume Yamaha and NGK have a very specific theoretical amount of how much this should occur.

Unfortunately this phenomenon increases with heat and pressure. As these engines need to be run in the top 20% of their rpm range just to get the boat up on plane, spark plug life is really short moving down to avation levels of about 100 hours.

If boat dealers are charging $500 for oil plugs and filter change I have no intention on finding out how much they charge to drill out a seized plug and insert a heli-coil.

anyways... this avation forum thread has a great bit on the types of anti seize, how to apply, Bosch, NGK, and Champion guidance, the choice if to apply or not, and the inportance of the torque value...

http://forums.pelicanparts.com/porsche-911-technical-forum/475238-anti-seize-spark-plugs.html

Keep in mind that they are talking avation where the stakes are a litte higher than our 300 hp bar slash swim platforms.

Good read, but it sounds like there is not one conclusion... At the end - what do you do? Do you use anti-seize and torque with torque wrench?

--

 

[swatski]

Unfortunately it's not the top part of the plug that rusts. It's the threads. The theory is that #3 valves often stay open on shutdown allowing moisture to contact the plug threads. I don't know if this theory holds any water or not but it's almost always #3 that rusts and breaks. I'm sure crc would burn off if applied to the threads so that's why we use antiseize.

Great point. I did not think of corrosion due to moisture coming from within the cylinders!
There is solid evidence for #3 cyl issues in MR-1s, no doubt.
I guess, personally, I'll stick with my non-anti-seize schedule as I change plugs very often anyway. But it may be better to use it if boating in salt, I can totally see it. I think I would, after reading this thread.

--

 

[scot71]

I use anti-seize, finger tighten, then 1/2 to 3/4 turn to tighten. Never had a problem with getting them out or a plug malfunctioning. I tend to subscribe to the KISS principle.

 

[Gym]

I use anti-seize, finger tighten, then 1/2 to 3/4 turn to tighten. Never had a problem with getting them out or a plug malfunctioning. I tend to subscribe to the KISS principle.

This IS the procedure to use if antiseizeing your plugs as the torque spec assumes a dry plug thread. Torquing a treated thread would actually result in an over torque possibly causing a new plug to snap on installation.

 

[Zizzou 192]

18.4 ft lbs is not alot of force.

Basically the force of an 18.4 lb weight pulling down on the end of a 12 inch wrench.

i assumed the value was listed to prevent overtightening.

Overtightening increases galling which is a major force making the plug threads fuse into the engine head (along with galvanic corrosion). Anti seize "helps" pervent permanant fusing of the various mystery metals. Anyone that ever tried to get lug nuts off an old truck even with anti seize can tell you all about the only "helps" part.

I am not expereienced enough to guesstimate that one by hand, let alone to feel the -10 % from that value to account for the small amount of lubrication that brand X anti seize allegedly provides.

I am fortunate to have a Snap On Tech Angle digital torque wrench laying around that goes down to 5 ft lbs, near finger tight torque, to caress and use when experience / confidence is lacking or in case that good old timing chain decides to hatch unexpectedly one day.

There are some nice mini torque wrenches out there that can accurately measure in that range as well that are especially useful for messing around with bicycles.

 

[swatski]

18.4 ft lbs is not alot of force.

Basically the force of an 18.4 lb weight pulling down on the end of a 12 inch wrench.

i assumed the value was listed to prevent overtightening.

Overtightening increases galling which is a major force making the plug threads fuse into the engine head (along with galvanic corrosion). Anti seize "helps" pervent permanant fusing of the various mystery metals. Anyone that ever tried to get lug nuts off an old truck even with anti seize can tell you all about the only "helps" part.

I am not expereienced enough to guesstimate that one by hand, let alone to feel the -10 % from that value to account for the small amount of lubrication that brand X anti seize allegedly provides.

I am fortunate to have a Snap On Tech Angle digital torque wrench laying around that goes down to 5 ft lbs, near finger tight torque, to caress and use when experience / confidence is lacking or in case that good old timing chain decides to hatch unexpectedly one day.

There are some nice mini torque wrenches out there that can accurately measure in that range as well that are especially useful for messing around with bicycles.

Torque values are for dry threads (without lubrication), unless specified otherwise.
Anti-seize compound is a lubricant.
Accordingly, you would need to reduce the torque on spark plugs..., right? (To help prevent stripping threads, particularly in aluminum block engines.)

How much? IDK. 30%?

--

 

[Sbrown]

Torque values are for dry threads (without lubrication), unless specified otherwise.
Anti-seize compound is a lubricant.
Accordingly, you would need to reduce the torque on spark plugs..., right? (To help prevent stripping threads, particularly in aluminum block engines.)

How much? IDK. 30%?

--

I've seen articles about the whole anti-seize on spark plugs debate that recommend reducing torque by 1/3 of the value. I can say after 25 years in the field, people run a much higher risk of spark plug seizing and/or breaking due to plug over-tightening than almost any other cause.
At the end of the day, it seems like there are a lot more arguments for not using anti-seize on spark plugs, and only one argument for.

As far as torque wrenches go, regardless what brand you opt for, all torque wrenches are notoriously inaccurate at either extreme end of the scale. I personally use an inch-pound torque wrench for most of these lower end torque requirements. 1 ft/lb = 12 in/lbs.