Topic: Burnt ceramic on spark plugs

[blackdiamond]

Hey V-Man,

Because of my weird curiosity about this stuff, if your situation happened to me, I would call the plug manufacturer and see if I could talk to a technical person.  And I would ask them if they would be interested in looking at all 8 of their spark plugs and possibly getting me some accurate analysis for the cause of premature failure – which obviously is NOT corona stain.

I completely understand the “corona stain” cause, and according to video that Bgen posted, “it’s normal and harmless and does not cause any issue with performance.”  But the video did say “not to be confused with exhaust gas blow-by or bad seals in the spark plugs”.  So from that video, I assume that “bad seals” do occur.  I personally have never experienced that.

Anyway… just posting more pomp ‘n stink.   

Gnarls. 

Any chance there's a video (I have not looked) showing the expected results from exhaust gas blow-by or bad seals?  I read this statement more of an acknowledgement that people will mistake the corona stains to be from gas blow-by or bad seals, but not that they necessarily look anything alike.

[Gnarly4X]

My interpretation of that video is different.

Clipped for here:  http://ricksfreeautorepairadvice.com/cause-spark-plug-failure/

"Excessive torque damages spark plug seal.
Spark plugs consist of a hollow threaded shell and a porcelain insert. When you tighten a spark plug too much, you distort the shell and break the shell-to-porcelain gas seal or cause a hairline fracture that results in misfires. In fact, spark plug manufacturer NGK says that improper torque is responsible for 90% of spark plug warranty claims. Bad plug? Yeah, you probably caused it yourself."

Based upon V-Man's descriptions, my guess is that there is a reasonable chance that the alleged over-torqued spark plugs caused a seal failure and that is what caused the misfires.  The corona stains, if that's what those stains were, had nothing to do with misfires.

Gnarls.

[:)bestgen4runner]

Interesting stuff.
I still think it's wild that in 20+ years of working on cars and truck I have never seen this happen.
Honestly I have never used or seen a torque wrench used to install spark plugs.

[V-Man [OP]]

Interesting stuff.
I still think it's wild that in 20+ years of working on cars and truck I have never seen this happen.
Honestly I have never used or seen a torque wrench used to install spark plugs.

Yet the torque setting for my Tacoma's and Karen's 4runner's spark plugs are only 12-14 Ft/Lbs.

    I never used a torque wrench before, but never tightened them down that tight.  After I got a Torque wrench with low enough setting( 6Ft/Lbs minimum) I started to use it on the plugs, and was surprised at how little force it took to reach 13 Ft/Lbs. I can exert 13 Ft/Lbs of force and get the wrench to click with just one finger.  I have been over torquing sparks plugs for years.
I don't think people normally would be over torquing the plugs by much, but even if they over torque them it's not likely to be enough to damage the plugs.   


It took a lot effort to take the plugs out, I had to really put my back into the work. They were way way over torque.

[:)bestgen4runner]

The issues I have seen the most over the years when it comes to spark plugs.
#1 not tight enough when installed. spark plug backs off and tears threads out of cyl. head. (lots) Most likely caused by installer using a torque wrench (  joke)
#2 not tight enough then leaks combustion gasses into spark plug tube resulting in damaged threads and a cooked coil. (often)
#3 cross threaded spark plug threads in the head. (once or twice a year)
#4 cracked spark plug (the porcelain)
#5 use of the incorrect spark plug. (once a year or less)
Over torqued spark plugs causing an issue (never seen it to date)
I asked a couple of the guys I work with that have been here longer than Me. They mentioned the above list but none have ever seen an over torqued plug issue.   

[Gnarly4X]

The issues I have seen the most over the years when it comes to spark plugs.
...  but none have ever seen an over torqued plug issue.   

I also have not experienced an over-torqued spark plug that was damaged.

I also do not use a torque wrench when installing spark plugs.  In the past I have checked the torque amount with my torque wrench and felt like the amount of spec’d torque was way too much.  I have always just gone by my hand/arm “feeling”.  For most bolt and nut tightening, I tend to under torque and some Toyota Factory Service Manual torque specs are too high or don’t feel tight enough. 

For example:  Toyota FSM says Clutch cover to flywheel – 14 ft lbs.  That is not enough to me, so I end up closer to 20 lbs.  Intake manifold to head – spec’d at 14 lbs… seems a little light.  Exhaust manifold to head – 33 lbs .. seems a little too much.  It’s way easier to check the bolts and nuts after 100 miles rather than strip or break off a stud.

I’ve doing my hand/arm torque "specs" for a long time and haven’t had any issues so far.

Gnarls.

[V-Man [OP]]

The issues I have seen the most over the years when it comes to spark plugs.

#4 cracked spark plug (the porcelain)
#5 use of the incorrect spark plug. (once a year or less)

I am thinking you may have the best answer we will ever get with #4.  I did check if the plugs were the correct.

So if the Porcelain( or seal) was cracked, how would it happen? Also how did it happen to eight plugs at the same time?  I am not sure we will ever get a definitive answer outside of a lab, so cracked porcelain( or seal) will have to do.

Bgen do you think using a normal socket and not a Plug socket would make any difference? I can't see it but strange things happen.

[Gnarly4X]

Hey V-Man,

I think it is logical that there are 2 likely possibilities:

1 – the plugs were defective out of the box.  This is a possibility, but not very likely. Denso tests these plugs, they are pre-fired.  In the realm of production, quality control, quality assurance is it possible the plugs got passed their quality inspections, etc?.... maybe, but odds are probably very slim to none.

Denso is one of, if not the most quality and significant global supplier of automotive parts, and especially to Toyota.

2 – the spark plugs were damaged, seal cracked or broken, during installation.  How?  It appears the over-torquing is what will do that.  And, with your description of how much strength it took to loosen them, the over-torqued cause is likely.  Could the dealer technician mistakenly used the wrong torque specification for those plugs? ….  28 to 34 lbs. instead of 13 to 15 lbs?

It seems from what has been posted here and the links to some other similar issues. The corona stain is not uncommon, but appears to be something not seen by many.

Spark plug sockets are different and have the rubber insert to grab the tip of the plug. Both of my spark plug sockets are 6 point and the same length as the standard sockets.

As I mentioned, I’d call Denso, and I would want to have conversation with the Service Manager at the dealership where the plugs were install last.

Gnarls.

[V-Man [OP]]

Hey V-Man,

I think it is logical that there are 2 likely possibilities:


2 – the spark plugs were damaged, seal cracked or broken, during installation.  How?  It appears the over-torquing is what will do that.  And, with your description of how much strength it took to loosen them, the over-torqued cause is likely.  Could the dealer technician mistakenly used the wrong torque specification for those plugs? ….  28 to 34 lbs. instead of 13 to 15 lbs?

Spark plug sockets are different and have the rubber insert to grab the tip of the plug. Both of my spark plug sockets are 6 point and the same length as the standard sockets.

As I mentioned, I’d call Denso, and I would want to have conversation with the Service Manager at the dealership where the plugs were install last.

Gnarls.

I did talk with the service Manager at length, and he was of the option that damage was done during the installation.   I know plug sockets have the rubber insert, but gripping the tip for insertion or extraction is it's main function.  A normal socket without the insert should not damage a plug the way I see it, but maybe Bgen knows of a reason it could.

Just to be clear:

The problems developed over time, and were not present from the moment the new plugs were installed.  Over the course of three months the fuel mileage did decreased,  but the main problems were the 4runner got harder and harder to start( had to be cranked long before it would start), and it became more and more sluggish in the throttle response.

If the problems had developed over a couple years I probability would have thought it was just time to change the plugs , but three months got my attention. 

[:)bestgen4runner]

I agree that a standard socket would not have damaged the plugs during installation.
In regards to my #4 cause (cracked porcelain) this has always been to the white visible section of the plug and is felt in the form of a ignition missfire. Complete loss of a cylinder as apposed to a reduction in available spark intensity.
At this point We will have to see if the vehicle is completely void of the issues that it had been experiencing.
Time and mileage will be the answer to our disbelief that all eight spark plugs had been damaged during installation.
Please please keep us in the loop on this repair as I’m sure We would all like the satisfaction of know the long term answer.
Thank you to V-man for an interesting and educational thread

[79coyotefrg]

It is a 2004. The O2 sensor may have leaned out the air fuel  if it was rich, it may made the air fuel richer if it was lean. I can't say for sure, just a speculation.    But since I don't drive the 4runner except for a test drive when Karen said it was not running well, I am starting with what I was told, and then what I observed on the test drive.

Yes every one of the plugs failed the test. 

First I thought clogged fuel filter it's 15 years old on the factory filters( you know were those are right? ) but at least there are new ones in there now. No improvement.

If it had a distributor and not electronic ignition I would have said the timing was off, not far off but off.

 

timing belt slip?  how many miles does it have??

[V-Man [OP]]

I agree that a standard socket would not have damaged the plugs during installation.
In regards to my #4 cause (cracked porcelain) this has always been to the white visible section of the plug and is felt in the form of a ignition missfire. Complete loss of a cylinder as apposed to a reduction in available spark intensity.
At this point We will have to see if the vehicle is completely void of the issues that it had been experiencing.
Time and mileage will be the answer to our disbelief that all eight spark plugs had been damaged during installation.
Please please keep us in the loop on this repair as I’m sure We would all like the satisfaction of know the long term answer.
Thank you to V-man for an interesting and educational thread

No problem, I'll try to get an update to you in Say three months? If the Problems return it should be in about three months. 

Just one last question.
 
 Karen says that before I changed the plugs it was super hard to start when cold. She had to crank and crank it, then it would half-butt fire and then catch and start.  I never started it when the motor was cold, but it did take a few cranks to get it to fire and run. 

If the motor was misfiring, could have only been doing it when it was cold. Once the motor warmed up it did not misfire anymore?   

I don't drive it so I am trying "Pry" info out of her. You know how that can be. 

[EASYRYDERDANGER]

after reading through 1.5 pages i realized people are arguing over the dumbest on here. And who ever thinks that little brown ring around the spark plug causes misfires is a gullible poor b*std.  I have some ocean front property to sell you in Idaho... besgen, lol, so humble in wanting to find the "correct" answer, stop fooling yourself on here.  You dont take tax advice from your plumber do you?  Flame on

[300k]

And who ever thinks that little brown ring around the spark plug causes misfires is a gullible poor b*std.

Yeah and the little knock knock sound coming from the bottom end is just the milk man knocking on your engine 

[Gnarly4X]

after reading through 1.5 pages i realized people are arguing over the dumbest on here. And who ever thinks that little brown ring around the spark plug causes misfires is a gullible poor b*std.  I have some ocean front property to sell you in Idaho... besgen, lol, so humble in wanting to find the "correct" answer, stop fooling yourself on here.  You dont take tax advice from your plumber do you?  Flame on

EASYRYDERDANGER,

You are WAY too late to the party.  Pull up your pants and go home. 

Gnarls.

[AZ Rockit]

You dont take tax advice from your plumber do you?

Dear Jesse,

My plumber works a second job at H&R Block. SO, yeah, I do take tax advice from my plumber.

[EASYRYDERDANGER]

Lol, fish on.  Lets start a new topic, gnarly you start it, you know how to over analyze bs that doesn't account for anything.  Hmmm thinking, oil filter torque spec maybe, and the stress it puts on the block if over tightened?  Ya ya, that sounds great, please research, 300k Google.  And no knock for me, but ty for the shout out.

[AZ Rockit]

Lol, fish on.  Lets start a new topic, gnarly you start it, you know how to over analyze bs that doesn't account for anything.  Hmmm thinking, oil filter torque spec maybe, and the stress it puts on the block if over tightened?  Ya ya, that sounds great, please research, 300k Google.  And no knock for me, but ty for the shout out.

Okay, looked at Old Red's removed spark plugs...similar brown ring...

[AZ Rockit]

Okay, looked at Old Red's removed spark plugs...similar brown ring...

1, 3, and 4 had the brown ring. 2 did not.

[:)bestgen4runner]

 
Nothing to see Here folks. Just keep moving along. Same different day.

[AZ Rockit]

Nothing to see Here folks. Just keep moving along. Same different day.

Yeah, that was my point, but I'm not a Toyota Nazi expert like you, so I am guessing...

[:)bestgen4runner]

I work at a Chevron Gas Station? ask anybody that knows Me and they will tell You the same thing.

[EASYRYDERDANGER]

Im a front yard mechanic.  And i bet your silly aftermarket wire insulator boot fit fully over the one plug

[300k]

And i bet YOUR silly aftermarket wire insulator boot fit fully over the one plug

We didn't put that crap on there! Might know the guy who did

[blackdiamond]

Lol, fish on.  Lets start a new topic, gnarly you start it, you know how to over analyze bs that doesn't account for anything.  Hmmm thinking, oil filter torque spec maybe, and the stress it puts on the block if over tightened?  Ya ya, that sounds great, please research, 300k Google.  And no knock for me, but ty for the shout out.

I think the most entertaining thing on this entire thread is finding out the Gnarly has a list of things that he doesn't trust the Factory Service Manual specification for torque on.  It just goes to show that we all choose what we want to believe and trust.  Why trust the people that designed and built it when you can over research and over analyze and form your own opinion.  I think the majority of us fall into the category of people that assume if what we're doing has worked then it must be the best way when instead the method likely just matters less than we care to admit.

[emsvitil]

Lol, fish on.  Lets start a new topic, gnarly you start it, you know how to over analyze bs that doesn't account for anything.  Hmmm thinking, oil filter torque spec maybe, and the stress it puts on the block if over tightened?  Ya ya, that sounds great, please research, 300k Google.  And no knock for me, but ty for the shout out.

Oil filter torque:   As tight as I can gripping with with my clean hand on clean outside case (no oil on hand or filter)


Block stress:    No problem.    But if you overtighten a cast remote filter adapter (block side), they can fatigue crack at the threads and the adapter eventually breaks off while driving and you lose all your oil...… (And it takes awhile for that oil pressure gauge reading 0 to sink into your brain)

Then you walk to and from the store to get some oil and put the filter that was on the other end of your remote filter adapter on the block (It's nice that the 22RE uses the same filter that is commonly used by remote filters).    It's also nice you can access everything from the top and thru the wheel well.

And no damage to engine.   

[Gnarly4X]

I think the most entertaining thing on this entire thread is finding out the Gnarly has a list of things that he doesn't trust the Factory Service Manual specification for torque on. 

Hey bd,

Wow… I think the most interesting thing on this entire thread is YOU finding ME with a list of things I don’t trust “most enteraining”. 

OK… why don’t you take 30 seconds, do a Google search on the number of FACTORY manufactured automobiles in the past 10 years with serious “design and built” manufacturing defects and multi-millions of recalled vehicles!!

You are right, I do not trust everything manufactured.  And, yes, I do extensive “over research” and I “over analyze”, and I form my own opinions.

My dad was an old school auto mechanic.  I don’t remember him ever using a torque wrench.  I do remember  him snapping off or stripping a nut or a bolt once in awhile.  As I watched his reaction (I learned a new cuss word every time he did it), so I formed my own opinions about tightening nuts and bolts.

There are a few torque specs listed in my two Toyota Factory Service Manuals that I do NOT use.  Like I said… the specified foot pounds seem either too loose or too tight.  And so far, it has worked for me.

On my ‘85, the spindle to knuckle torque spec is factory 38 lbs.  The first time I did an R&R on the front hub assembly, I torqued the spindle bolts by hand about where I felt comfortable.  Then I took my torque wrench and checked to see I was about 25 lbs.  I went to 30 lbs on one bolt and stopped. At that point it felt like I could strip or snap off a bolt if I increased the torque number.  I was NOT using anti-seize compound.  If anyone has recently torqued down those bolts, I’d really like to know if 38 lbs felt OK to you.

Gnarls.

[Gnarly4X]

.... gnarly you start it, you know how to over analyze bs that doesn't account for anything.

Hey E,

So... if we were to go through your 152 posts here, would we find any
"over analyzed bs that doesn't account for anything."   

Gnarls.   

[Gnarly4X]

Im a front yard mechanic.  And i bet your silly aftermarket wire insulator boot fit fully over the one plug

Is a "front yard mechanic" anything like a "Toyota Nazi expert"?   

Those are brand new words for me. 

Gnarls. 

[Gnarly4X]

Oil filter torque:   As tight as I can gripping with with my clean hand on clean outside case (no oil on hand or filter)

Geezzz e... you beat me to it.

You should just start a new thread for EasyD, and not fubar this very interesting corona-stain-engine-misfire-over-torqued spark plugs discourse. 

Gnarls.