Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert! (1 Viewer)

[Mike NXP]

Okay...I'm doing plugs and coils tomorrow.
Denso Iridium TT's and OEM coils.

I know not to use anti-seize on the plug threads but what about dielectric grease in between plug and coil?

For sure, it doesn't require a lot just a little dab so it's easier to remove the coil next go around .

Keep everything clean. Like you said no antiseize and just snug it all up. I go with the technique on the spark plug box , something like hand tight then 3/4 turns with socket

 

[Trapper50cal]

For sure, it doesn't require a lot just a little dab so it's easier to remove the coil next go around .

Keep everything clean. Like you said no antiseize and just snug it all up. I go with the technique on the spark plug box , something like hand tight then 3/4 turns with socket

Thanks!

 

[Trapper50cal]

...
I've had occasions. Where I've had to use a 3/4" breaker bar to get spark plugs out, when anti-seize used.
That was after months of adding 44K to gas tank repeatedly and penetrating oil into spark plug tube. First tried 3/8" breaker bar, than 1/2" and finally had to get out the big-boy 3/4" breaker bar. Talk about risky! It was a "hail-mary-pass" last effort. Not just the breaking loose, but almost every turn of getting all the way out was very difficult. Only the last few turns didn't take extreme force. I was shocked, I didn't bust the spark plug in the head or damage the threads. Not something I'd like to even attempt again.
...

This, I think, is exactly what I was just experiencing. Super tough coming out and had to GENTLY use a breaker bar on one.

 

[Trapper50cal]

Do these threads look like anti-seize was used and then baked?

not a great pic, sorry.

 

[2001LC]

Do these threads look like anti-seize was used and then baked?

View attachment 3856203

not a great pic, sorry.

Likely!

 

[OBXJ]

I think this has been posted before, but here it is again:

"NGK spark plugs feature trivalent plating. This silver or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without lubrication or anti-seize.

"Anti-seize can act as a lubricant, altering torque values up to 20 percent, increasing the risk of spark plug thread breakage and/or metal shell stretch. Thread breakage can sometimes involve removing the cylinder head for repair. Metal shell stretch changes the heat rating of the spark plug and can result in serious engine damage caused by pre-ignition. Do not use anti-seize or lubricant on NGK spark plugs. It is completely unnecessary and can be detrimental."
NGK: Five Things You Should Know About Spark Plugs

I've heard the 20-30% torque increase with antiseize quoted many times in many places. I'm sure its based on actual data, but I recently saw a video (skip to 16:39 for relevant segment) showing a 100% torque increase when lots of antiseize was applied to a M14 bolt. Not apples to apples with spark plugs but wow ! That youtube channel is great; they seem to have sound practices and precise instrumentation.

 

[ScotyDosentKnow]

I have new plugs for my Cruiser and am a little psyched out about replacing them now after reading this thread

 

[NE Snowman]

I have new plugs for my Cruiser and am a little psyched out about replacing them now after reading this thread

mine were easy. Plugs got replaced once before my ownership. I ended up replacing all my coils as well because 7/8 had cracked.

 

[LJE]

I like to call this photo "guess which sparkplug wasn't even finger tight?"

While not a 100 series, this was a 2008 V8 VVTi 2UZ 4runner with 169K on the odometer, and my bet is these are original plugs. None of the other 100k mileage maintenance was done on it.

Glad this was brought to me now - I think this one was close to liftoff!

EDIT: Mud hates my phone right now... Will upload photo later.

 

[Jack90210]

I have new plugs for my Cruiser and am a little psyched out about replacing them now after reading this thread

Install dry, torque to 18 ft/lb, done.

 

[94SRUNNER]

Install dry, torque to 18 ft/lb, done.

Ditto. I did this about 3 years ago and have checked every 6 months to a year and it has always been at spec.

 

[ScotyDosentKnow]

Install dry, torque to 18 ft/lb, done.

I'm not worried about installing them, I'm worried about taking them out.

 

[Jack90210]

I'm not worried about installing them, I'm worried about taking them out.

That's a fair point. Best I can say is that rocking them back and forth (loosen/tighten) is helpful. Be sure to blow/vacuum any debris out before removing.

 

[privatebri]

Install dry, torque to 18 ft/lb, done.

I completely get the dry plug rationale.
Is the 18 ft/lbs a best practice kind of thing?
Got my 2000 LX in ‘04 and did the plugs twice both with anti seize. Won’t do that this time around!

 

[pwil393]

Finally was able replace all my plugs and one coil. Guessing the plugs were from 90k mileage maintenance via Toyota. Looks like anti-seize was used and the one coil (#5) had a crack running up one side. Current mileage on truck is 246,515.

The #5 plug was stuck for weeks. Had replaced 7/8 plugs 3 weeks to a month prior. Using Mud I found a thread about stuck plugs and I ended up using 3 cans of BG 44K fuel additive to help loosen it. (I’ll link thread, if I can figure it out).

Thread 'Seized spark plug 6'
Seized spark plug 6 - https://forum.ih8mud.com/threads/seized-spark-plug-6.1273403/

Installed new plugs dry and torqued to 18’ Ibs. Shout out to @2001LC for this thread and tips on stuck plugs and BG 44K.

 

[ScotyDosentKnow]

That's a fair point. Best I can say is that rocking them back and forth (loosen/tighten) is helpful. Be sure to blow/vacuum any debris out before removing.

Was bored and decided to change plugs this afternoon. No issues with the plugs and all coils looked great at 235K miles, don't know what I was so worried about lol

 

[NE Snowman]

the 18 ft/lbs a best practice kind of thing

I can’t recall where that started most likely this thread?
When installed and carefully setting them, you’ll feel the 15lbs not set, at least in my truck. You could really feel them bottom out and snug tight at 18lb

 

[LJE]

I can’t recall where that started most likely this thread?
When installed and carefully setting them, you’ll feel the 15lbs not set, at least in my truck. You could really feel them bottom out and snug tight at 18lb

IIRC 18 ft-lbs is the lowest that both Denso/NGK recommend for the plugs, vs Toyota's 15 ft-lb spec.

 

[2001LC]

IIRC 18 ft-lbs is the lowest that both Denso/NGK recommend for the plugs, vs Toyota's 15 ft-lb spec.

Actually 13ft-lbf is Toyota spec. The 18ft-lbf is a torque, I came up with. It was based on a few things:

• Denso mid range for aluminum heads (at time of OP).
• Where I sung firm, then turn 2/3 turn.
• Where I feel crush washer give way, at ~17.75ft-lbf , torque wrench drop back to 17ft-lbf and then a very solid stop feel at 18ft-lbf.

Safest, is the Toyota 13ft-lbf. To date, I've not had issues at 18ft-lbf. Has it help increase time until walk-out. IDK.

A test, I've not tried:

1. Torque cylinders/plugs 1, 3, 2 and 4 to 13 ft-lbf.
2. Torque cylinders/plugs 5, 7, 6 and 8 to 18 ft-lbf.
3. Check plugs in 7 yr/90K miles, in a typical daily driver. About 12.5k miles a year for 7 years. Which is ~4,500 heating and cooling cycles.

What I would not do:

• Torque less than 13ft-lbf.
• Torque more than 18ft-lbf
• Lube threads.

Today, I see Denso has re written their install page.

SPARK PLUG

DENSO spark plugs use iridium alloy for their center electrode. Because of its extremely narrow diameter of just 0.4 mm, engine output and acceleration response are greatly improved.

am.denso.com

 

[privatebri]

Very helpful details.
Thanks guys.
I will be torquing to 18 when I change my son’s ‘07 4Runner plugs next month.