[Bitter]

Get a spark plug socket and get the correct normal size ratchet, you may also need to buy an extension. The plugs will be in there hard but once you get them loose you can spray some carb cleaner and work them back and forth, the cleaner will work into the threads and dissolve the varnish holding them in place. When I changed plugs at 80,000 miles on my 2ZZ they were in real good, was a heck of a work out.

 

[Bitter]

An upgraded spark plug is the Denso IK20TT which also goes by the part number 4702. I find these plugs to run very smoothly and maintain their performance for a very long time. My idle is a lot better with these spark plugs over the standard Iridium plugs I had before.

The 16 heat range plug is for the 1ZZ-FE engine, the 20 heat range plug is for the 2ZZ-GE engine with higher compression. Many application lookups online don't differentiate between the 1ZZ and 2ZZ in the Corolla for whatever reason.

 

[Bitter]

Denso has been selling this same style of plug for a while in Japan as the SIP (Super Ignition Plug) and they come from the factory in the newer Corolla. I changed out a set at 105K (a little early per maint schedule) in a 2010 Corolla (Uber car, big commuter too) and they looked like they'd barely worn at all and probably could have gone another 50K miles or more easily.

Here's a paper that talks about the twin tip plug design some in it's relation to making a better M10 (yea they shrunk spark plugs now too!) spark plug
http://www.globaldenso.com/en/products/aftermarket/plug/topics/2005/pdf/SAE-M10.pdf
There's some things in there related to the twin tip design and it's virtues in smaller plugs, which carries over to the larger M14 plugs that this engine uses. It's all around a more efficient design and for the price they're not really any more expensive than a standard style Iridium spark plug and cheaper than some specialty spark plugs even.

 

[Bitter]

I found my Iridium IX plugs worn to the point of causing a rougher idle at around 30K miles (60K KM). The Iridium center electrodes were mostly OK, it was the ground strap that had eroded away which makes sense, it's the weakest part. The 2ZZ is a little harsher on spark plugs with it's high compression and higher output in 'lift' so I'd plan on a 30K check of the Iridium IX spark plugs. The Iridium TT plugs though, all the sparky bits are long life materials, easy 60K mile plug in the 2ZZ and should really be good for more than that.

 

[Bitter]

Bitter. I have an 05 corolla. I like to try the Denso twin tip plugs just as a comparison against the denso iridium long life plugs I always you. I like to see how much better the twin tip really are. Thanks.

Make sure to get the correct heat range, I believe you'd be a IK16TT but consult an application guide to be sure.

 

[Bitter]

Ford 5.4 Triton engines were famous for stuck and broken off plugs. Ford put out a TSB for removal:

1. Make sure the engine is warm (hand touch after cooling down)
CAUTION
DO NOT REMOVE PLUGS WHEN THE ENGINE IS EXTREMELY HOT OR COLD SOAKED. THIS INCREASES THE CHANCE THE THREADS COULD BE DAMAGED.

2. Back out the spark plugs, no more than 1/8 to 1/4 of a turn. Apply penetrating oil (AeroKroil or equivalent) and fill the spark plug well just above where the jamb nut hex sits. A minimum period of 5 to 10 minutes of soak time is required.

3. Slowly turn the spark plug out. Some screeching and high effort may be noticed but not in every case. The expected removal torque is about 33 lb-ft (45 N•m) but should decrease on the way out. If it is higher, try turning the spark plug back in a half turn, then back out again. If the turning torque still seems high, repeat the back and forth rotation along with some penetrating oil to reduce turning effort.

Some guys swear by following the TSB + running a tank full of seafoam before attempting spark plug removal:
https://www.reddit.com/r/Justrolledintotheshop/comments/x8uwp/successful_ford_54_spark_plug_removal/

If it's the 3 valve Triton you just break the extended part of the plug off and use the extraction tool. It sounds terrible but it works great! I'll find a video or something g but don't want to get too far off topic.

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[Bitter]

Bitter, what corolla do you have. Thanks

I have a 2000 Celica GTS and formerly a 93 Prizm LSi. The Celica is a 2ZZ-GE engine which is fairly similar to the 1ZZ-FE in a few regards. I'm an auto tech so I work on a wide range of vehicles.

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[Bitter]

Sure, that may be the OEM appoved way to service Ford Triton plugs, but their plugs are very different in design which requires special service methods and should not be taken as general service advice for other vehicles.

I'm of the belief that nothing on a vehicle is "lifetime" or "long-life" regarding service interval, not for wear items. If an OEM claims that an item, part, or fluid, etc. is "lifetime" then a consumer should assume that means either only as long as it is still under warranty, or the estimated span of time that the first owner will use the vehicle. After that first 50,000 to 80,000 miles (give or take) all bets are off. A "lifetime" transmission fluid will be so worn out and dirty by the time it hits 60k-100k miles that you'll be lucky if you don't need a rebuild. You'd also be so lucky if the OEM even decided to put a dipstick on the transmission (i.e. Mercedes Benz).
Those long-life spark plugs will still be technically functional after more than 50k miles, but the ground electrode might be worn and performance has decreased, or like in your case they're a pain in the ass just to remove.
Cars typically last longer if they are serviced more frequently than what OEMs suggest.

The Iridium twin tip plugs have a platinum ground so wear is greatly slowed, they truly are very long life spark plugs. The Platinum TT plugs are good too but I don't anticipate them to last longer than standard platinum plugs, 60k miles roughly. I have those in my Mazda because they're very inexpensive.

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[Bitter]

Ford actually depicts the proper method to remove oxidation seized spark plugs without damaging threads or breaking anything, as I carefully performed myself when required.

Maybe at lower miles that works, but even just turning them 1/8th of a turn to get the penetrant to soak into anywhere will break them when they're totally seized, then you pull out the spark plug body with a long electrode, the lower steel shell and ceramic remain in the head. I had one yesterday that spun the lower ceramic in the shell and I had to blow the plug out of the hole with engine compression since it just sat and spun once it was unthreaded. The steel shell unthreaded UP the body of the plug. Once it was blown out I could use the tool to extract the lower steel shell.

For anyone curious wtf I'm talking about

https://www.f150forum.com/f4/5-4l-3v-spark-plugs-engine-build-dates-before-10-09-07-a-56871/

There's a video of the tool in use, thankfully it's silent so you're spared the awful crunching, cracking, groaning, and generally dreadful noises I've learned to just accept as normal.

 

[Bitter]

It might work some of the time, but what tech can drive a customer vehicle around for a whole tank of gas OR tell the customer "here drive through this tank of gas with your engine light blinking and cylinder misfiring melting your cat converters". No tech, that's what. It's different if it's your personal vehicle, totally different. I get a F250 plow truck in cause it's running rough and can't make it up a hill on the highway and they need it fixed by last Tuesday. Maybe it's different over there in Mayberry...

 

[Bitter]

Bitter, what is better the platinum tt plugs or the iridium tt plugs. Thanks.

I would go with the Iridium TT for a longer service life, however if cost is the primary concern the Platinum TT are very inexpensive. I've got about 15 or 20K miles on them in my Mazda 626 and last I looked at them (around November last year) they looked to be in great shape still. I'm not sure what 'Titanium enhanced' means in regards to the ground strap but the projected point showed little wear vs what I've seen from conventional spark plugs, though my only personal point of reference for conventional plugs are in my old 93 which had advanced timing and was very hard on spark plugs.

 

[Bitter]

Yep, some penetrating solvent like deep creep or pb blaster will help out a lot but the main issue are that the last couple threads of the spark plug have varnish and carbon on them and that's gotta get pulled up through the threads all the way. They'll likely all be tight and annoying but probably won't break or strip, that's pretty rare for a Toyota, they used the good aluminum on these cars.

 

[Bitter]

I haven't used Kroil so I can't compare, we use WD40 at work cause it has a little more staying power, I blend it with carb cleaner in the plug well for penetrating stuck plugs. PB Blaster is pretty thin and mostly solvents, it should get in there pretty good too. SeaFoam deep creep spray works well too.

 

[Bitter]

Not personally, I haven't used it enough to judge it fairly. A lot of people swear by it and I can see that being so thin it sure would be able to penetrate rusted parts pretty well. If it was what we used at work I'd probably be happy with it too. For us WD40 is more versatile.

 

[Bitter]

Try both, see what works best for you and your situation.

 

[Bitter]

Why are people recommending penetrating oil? Unless the spark plug is not sealing properly (the engine would run poorly) there is no way oil is going to get into the threads. The plug seals against 200 psi. Don't use anti-seize the threads are already coated and designed to prevent seizing in the head.

Sometimes the varnish that gets pushed up into the threads makes them total hell to remove, it acts like loctite and they squeal and stick and struggle the whole way out (the plug and the guy turning it), if you put some penetrating oil in the plug well and get the plug loosened a little it'll start to creep down and when you work the plug out and back in it gets forced down and lessens the chances of pulling up threads.

 

[Bitter]

They'll be fine as is.

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[Bitter]

The .1 mm difference is well within tolerance allowed, it'll be fine especially given how much less shrouded the gap is even if the gap is slightly smaller. 10% smaller won't give you 10% less anything.

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