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So you're doing the "Google it" thing. That's always helpful

 

My guess is 50/50. I do.

 

Never. They did not come that way and in 45 years working on vehicles, never used Anti-Seize on spark plugs.

 

Do you use anti-seize on your spark plugs?

Love to hear about why or why not and the different theories out there.

Also let me know what plugs you use (OEM? Iridium?) and what brand anti-seize do you use (if you use it)

Use anti seize compound? Always in aluminum-head engines.

I've been using anti-seize on plug threads for 50+ years, probably the greatest number of plugs changed were on air-cooled 2-stroke motorcycle racing engines that typically ran very hot, and had plugs changed very frequently.

Caution is required so no anti-seize ever gets near the ceramic electrode insulator or the body insulator ... that means no smearing anti seize on the plug threads with a finger, and subsequently getting anti-seize transferred to ceramic surfaces.

I use a small 'acid brush' with bristles trimmed to about 1/4" to apply the material, only a tiny amount (grain of rice) worked into the thread roots with the brush, no blobs or globs visible on the threads, just a microscopically thin film.

Probably used more Never-Seez brand than all other brands combined, but had many different options to play with, moly disulfide, nickel, copper, and titanium disulfide fillers. Never saw much difference in performance, at least in spark plug applications.

Always reduced installation torque by ~15%

I've always used either NGK or Denso plugs for ALL applications, platinum or (later) iridium electrodes for all Toyota applications. For many years Toyota Owner's Manuals gave part numbers for both NGK and Denso plugs, but switched to recommending Denso only after about 2010, even though NGK listed 'equivalent' plugs with same heat range, etc.

(For many years, Toyota installed NGK plugs in one cylinder head, and Denso plugs in the opposite side from the factory on V6 engines. Not sure if the same practice was followed with the V8 engines.)

 

Use anti seize compound? Always in aluminum-head engines.

I've been using anti-seize on plug threads for 50+ years, probably the greatest number of plugs changed were on air-cooled 2-stroke motorcycle racing engines that typically ran very hot, and had plugs changed very frequently.

Caution is required so no anti-seize ever gets near the ceramic electrode insulator or the body insulator ... that means no smearing anti seize on the plug threads with a finger, and subsequently getting anti-seize transferred to ceramic surfaces.

I use a small 'acid brush' with bristles trimmed to about 1/4" to apply the material, only a tiny amount (grain of rice) worked into the thread roots with the brush, no blobs or globs visible on the threads, just a microscopically thin film.

Probably used more Never-Seez brand than all other brands combined, but had many different options to play with, moly disulfide, nickel, copper, and titanium disulfide fillers. Never saw much difference in performance, at least in spark plug applications.

Always reduced installation torque by ~15%

I've always used either NGK or Denso plugs for ALL applications, platinum or (later) iridium electrodes for all Toyota applications. For many years Toyota Owner's Manuals gave part numbers for both NGK and Denso plugs, but switched to recommending Denso only after about 2010, even though NGK listed 'equivalent' plugs with same heat range, etc.

(For many years, Toyota installed NGK plugs in one cylinder head, and Denso plugs in the opposite side from the factory on V engines. Not sure if the same practice was followed with the V8 engines.)

Death, Taxes and FJtest - thank you.

 

Nope

 

The threads on the better brands are treated ... so they recommend NOT using anti-sieze compound. And yes, they understand the service life.

If so inclined the instructions above by FJtest should be followed. Most apply way too much which can cause missfires if there is any amount on the last threads closest to the tip of the plug. More is not better.

 

Most of the major plug manufacturers claim that the threads on their plugs now have some special plating that reduces the tendency towards galling. Many also recommend against anti-seize, not because it isn't beneficial, but because they have seen so many instances where mis-applied anti-seize (as in applied with a trowel) has ended up on the electrode insulator, where it eventually fuses into a semi-conductive glaze, or on the ceramic body, where it can induce arc-tracking. In either case, mis-application can result in misfiring.

With plug change intervals now at 100K miles, I think that anything you can do that further reduces the chances of galling the threads in the heads is worthwhile.

Manufacturers of recip aircraft engines universally recommend the use of anti-seize on spark plugs, with the expectation that a licensed A&P mechanic understands how to apply it correctly and the potential worst-case consequences of doing it wrong.

 

I use OEM on my 08.... and replace them more often than is required..... so even in this brutal environment I don't have issues because they're not left in there for multiple years - so I don't use anti-seize.
I replace them every year or 2.

 

I also replace every two years. And that is only about 15 to 20K miles.

 

I’ve not had to change plugs in my last few cars as I sold them before they were due. Not sure what I would do with my FJ. I think they were done by the previous owner at the recommended interval. If they come out without a fuss, I’ll probably just do whatever was done the last time. If it’s a pain to get them out and no anti seize was used, I might consider it.

Somewhat related side story… My last car was powered by a German high compression twin-turbo v8 that was apparently designed such that the spark plug electrodes had to be properly timed in the combustion chamber, and of course the only way you could do this was by applying the exact right amount of torque when seating them. Obviously using anything on the threads would ruin any chance of getting them properly timed.

 

(big snip)
My last car was powered by a German high compression twin-turbo v8 that was apparently designed such that the spark plug electrodes had to be properly timed in the combustion chamber, and of course the only way you could do this was by applying the exact right amount of torque when seating them. Obviously using anything on the threads would ruin any chance of getting them properly timed.

I'm a bit skeptical about any manufacturer's requirement to 'index' the position of the ground electrode in any German production automobile engine ... can you provide a link to any source of manufacturer's data documenting this requirement?

I do know that at some point in the past dragster engine builders used solid copper plug gaskets of various thicknesses to 'adjust' the position of the electrode in the head, or just selectively fitted a bucket of plugs to find those that just happened to have electrode positions end up in the desired location, but I don't know if this was ever conclusively proven to affect engine performance.

Not a lot of hard data available on spark plug indexing, but there are some anecdotal writeups, like:
Spark Plug Indexing – Eaton Balancing

(This site has a HUGE amount of well-documented info on engine blueprinting, specifically covering the early Ford Y-block V8 engines, but a lot of the info is universally applicable.)

Other info:
How to index spark plugs
Gapping and Indexing - NGK Spark Plugs

 

Do you use anti-seize on your spark plugs?

Love to hear about why or why not and the different theories out there.

Also let me know what plugs you use (OEM? Iridium?) and what brand anti-seize do you use (if you use it)

I added a poll for ya.

 

I've had to remove too many frozen plugs from heads over the years, so I absolutely use the stuff, though very, very sparingly as mentioned above.

On a related note, if the hex ring ever shears off a frozen plug, good luck getting it out of the head...

 

I do just a bit on each one. I had a couple stubborn ones back in the day

 

Other end of the spectrum. I had a '57 Volvo that would somehow spit out a plug every few months randomly.

 

last spark plugs changed that had it on I had to use a breaker bar very carefully to get the plugs out.. I no longer use it.

 

Awe Hell No! Before using anti seize, I'd use red locktite. Imagine how many times a minute the cylinders are firing? the Heat? this is the source of 99% of vibration.
Now Imagine, one working its way loose and the compression of the ignition sending that plug as a projectile.
Stop skipping arm day at the gym and you can break any nut free.

 

Even better.... J-B Weld!!!

 

Yes, but just a very tiny amount. Like a dab the size of a BB per plug and roll the torque back to 13ft/lbs instead of 14ft/lbs

 

Another amazing thing achieved by Toyota engine designers is the valve train wear: although the manual recommends having the valve lash checked at intervals, I've never done it. When rebuilding my 25 year old, 200k mile Camry engine the Toyota master tech helping me said he never saw enough wear in the gap to require re-shimming and that it was his understanding the wear rates of the various parts in the system were developed so that they would tend to cancel each other out. Not sure if that was just his own experience, or if it was from his training, but it seems to be the case as I've not run in to much talk of doing it on Toyota engines over the years (for a long time I'd assumed they used hydraulic lifters but he set me straight on that).

 

This is absolutely true and either amazing engineering, or amazing luck. When I bought my 3rd generation 4Runner new in 2000 (3.4L V6), the 5VZ-FE engine had already been used in Toyota trucks for 5 years.

I asked the service manager at the dealership what the typical mileage was when the engines actually needed their first valve adjustment ... I was shocked when he told me that his dealership had never performed a valve adjustment on a 5VZ-FE engine. I thought he was FoS, and checked with a few other dealerships and got exactly the same answer, and at that time they were servicing vehicles that already had over 150K on them and valve clearance was still in spec.

We have one 3rd gen in the family with 270K miles, and another with just under 250K miles, and neither of them have ever required a valve adjustment and both idle as smooth as silk and are dead quiet.

Wear on the cam lobes, top and bottom of the bucket lifters, and on the tip of the valve stems would increase valve clearance, while wear on the valve seats and valve seating surfaces would decrease clearance, and somehow the wear rates seem perfectly matched.

I think the same situation exists with the solid-lifter single-VVTi 1GR-FE engines ... has anyone in the FJ 300K mile club ever required a valve adjustment?

What a far cry from the British pushrod sports car engines of the '60's that absolutely required a valve adjustment every 25 or 30K miles to keep them running half way decently.

 

Toyota does have some brilliant engineers, and some who are dumb as bricks... in particular, I'm looking at the guy who designed the camber adjustment bolts

 

A small amount of lubricant is a good idea. The threads on spark plugs, to me, seem purposely cut undersize, and I don't know what the logic is there. Personally, I would prefer to see a steel insert used.

 

"Stop skipping arm day at the gym and you can break any nut free."

The intent of using anti-seize has nothing to do with the 'effort' required to unscrew a spark plug ... it's to prevent the aluminum threads in the head from coming out with the spark plug.

A total non-issue with cast iron heads, potentially a big issue with aluminum heads, especially if it's an air-cooled engine, or the plugs stay in the heads for years.

 

I don’t use anti seize. If the plug is torqued to spec, and changed at timely intervals, it shouldn’t be necessary. Also, it’s not advisable where performance is a concern, it reduces conductivity.

 

Good video on the subject and it's sponsored by a spark plug manufacturer.

 

 

I was told as a kid to always use with aluminum cylinder heads.

 

Do you use anti-seize on your spark plugs?

Love to hear about why or why not and the different theories out there.

Also let me know what plugs you use (OEM? Iridium?) and what brand anti-seize do you use (if you use it)

I use anti seize on everything.

 

Do you use anti-seize on your spark plugs?

Love to hear about why or why not and the different theories out there.

Also let me know what plugs you use (OEM? Iridium?) and what brand anti-seize do you use (if you use it)

No, you should never use anti-seize on spark plugs! Heres why:

• It acts as an insulator affecting the total electrical conductivity of the spark plug. This is the opposite of the desired purpose of a spark plug
• You should be using NGK or Denso Iridium plugs at OEM spec, they both contain an anti-corrosive coating already applied at the factory its the silver or graphite like color of the plug threads.
• If your not careful and it drips onto the dielectric (contact) of the plug it will cause the plug to foul very quickly during use.
• It can cause the plugs to loosen and come out of the socket, and/or cause compression loss. (NOT something you want to happen at 70mph going down the highway, nor on a trail)

I have owned many vehicles and drive them for many 100s of thousands of miles, never had an issue with plug changes that anti-seize would have solved. Even if the plugs have been installed for 100k miles.