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Discussion Starter · #1 ·
A little background:

I live near WSIR. A buddy and I decide to go do some 1000' racing on one of their grudge nights.
Car performs (obscenely) well all night... until we leave.
Almost immediately after leaving the property, BAM, spark is being blown out under load.
I think very little of it as it is incredibly common that my particular ST eats a set of plugs once a week, it feels like.
Take the car home.
Park it.
Decide I will put my downpipe in the next day (Saturday) anyway and will just change the plugs at the same time because I've learned to keep a set around, and because I wanted to go another range colder as the car is now "stage III".

Saturday:

It's the desert, it's damn hot, so I get up early to get a jump on it before the pavement becomes actual lava.
Get the car up.
Wrestle with downpipe for a million years because my hands weren't made to make watches and they don't fit anywhere i need them to.
New downpipe DOESN'T FIT. Lower hangers are too long, downpipe is too short to meet my exhaust, impossible to install v-band clamp with hands like grapefruits, the usual debauchery. To try to get it to fit I have to do some "massaging", but to do this and not be standing on a downpipe supported at a single point by its upstream O2 sensor, I elect to remove it for the time being. NOPE. The threads did not agree and stayed behind.
Rejoice! Behold the splendor!
I intake a fresh face full of atmosphere, and start the hunt for an upstream O2.
Much the same as everything else I have ever needed for this car, nobody stocks it.
Part ordered, overnight it to me, I think I'll go to bed.

Wednesday 26JUL17:

Parts, arrived.
Morning, still.
America, FREE.
So I rise, ready for battle, and gather my things.
Downpipe first, after about 2.5 hours of most unconventional warfare, my first enemy hath been slain.
I lead the advance under the hood and begin removing plugs, which I have down to a science.
Plug 1, my usual first to die, looks okay. Surprised, I carry on, two, three, some oil, light erosion... then, number four.
As if it was Agent Smith, standing ready behind the commotion of combat, ready to counter my every move.
It comes out like every plug before it, without incident.
Put the hose on it, pull it out of the hole, immediately the color rushes from my face, my stomach heavy.
THE GROUND STRAP IS COMPLETELY GONE.
I have never thrown a rubber hose so far in my life.

I guess I figured out why my spark was blowing out.

Spent quite a long while improvising magnetic devices to try to find it inside my beloved cylinder 4, but to no avail.
I figured any damage is probably already done considering I drove it home in the same state.

Behaves quite fine with the new plugs on our way to have the exhaust made to bolt to the downpipe.

Today:

I drove it to work because its my daily and I have no choice.


tl;dr - #4 spark plug dropped a strap in #4 hot-hole after drag racing with my friends. Be safe out there. Modding cars is stupid.
 

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The spark plug ground may have managed to exit the cylinder without major incident.
And since the engine did not make horrible nasty (broken) sounds I would say your spark plug bit is safely gone.
Lot of turbulence in a working engine, More than enough to blow the plug bit out
and past the valve before it closed on the metal clump. Ditto not getting caught between the piston and the cylinder head at TDC.
So I would say 'Lucky Lucky'.

On the down side.. whatever is destroying plugs in #4 holes is most likely not doing your #4 piston any favors anyway..
If you have a tune I would certainly look into what is going on in hole #4 and your tune.
 

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Discussion Starter · #5 ·
The spark plug ground may have managed to exit the cylinder without major incident.
And since the engine did not make horrible nasty (broken) sounds I would say your spark plug bit is safely gone.
Lot of turbulence in a working engine, More than enough to blow the plug bit out
and past the valve before it closed on the metal clump. Ditto not getting caught between the piston and the cylinder head at TDC.
So I would say 'Lucky Lucky'.

I agree completely on the "lucky lucky" portion. Feeling incredibly grateful for that if it is the case.

On the down side.. whatever is destroying plugs in #4 holes is most likely not doing your #4 piston any favors anyway..
If you have a tune I would certainly look into what is going on in hole #4 and your tune.
I have not had a set of spark plugs last longer than 30k in this car (OE before I started modding the car). Usually its around 10k, which is right about where these were.
Usually #1 is the one that causes the trouble, but it has always just been an eroded electrode "pair" and what seems to me to be a very picky combustion process as far as ignition is concerned.
 

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I have not had a set of spark plugs last longer than 30k in this car (OE before I started modding the car). Usually its around 10k, which is right about where these were.
Usually #1 is the one that causes the trouble, but it has always just been an eroded electrode "pair" and what seems to me to be a very picky combustion process as far as ignition is concerned.
Our cars are notoriously hard on plugs.

It is commonly known to pull your plugs every other oil change, and check gap. Then adjust as necessary.

Also with the heat you are dealing with, going one step cooler may help your situation greatly.

Ask your tuner (if you are) about their stand on colder plugs.
 
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I haven't removed my OEM spark plugs yet, just hit 16k miles, nervous to do it as I haven't before, previously read how-to/sticky guide, I think it was by Deuce, gotta get spark plug socket, possibly anti-seize. Might as well replace if I'm gonna pull 'em, no?
 

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Fellow AV owner! Which ST are you? I was at the 2nd to last grudge night (the White ST with the Gold Snowflakes) Let me know if you need a hookup for photogenic stuff :)


Enjoyed the read, and I always keep an extra set of spark plugs, so if you are ever really desperate and all the parts places are closed. I'm local and have a set of Motorcrafts ready :)
 

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You didn't "drop" the electrode in the cylinder, you burned it off...it essentially vaporized, and blew out the exhaust. Detonation is usually the cause. I'd turn the tune down a bit, or next, you'll have chunks of the ring lands blown off. Anytime I've seen a burned plug, I've found other damage as well. You'll most likely at least find fine pitting around the edges of the piston...again, from deto.

You should NOT be eroding plugs. If you are, something is wrong. I know several guys with Escape 2.0s with close to 100k on them, with original plugs. It's not the engine.
And don't use anti-seize on the threads. There is no need. It just goops them up. A light coat of oil is all you need.
 
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Discussion Starter · #14 ·
Our cars are notoriously hard on plugs.

It is commonly known to pull your plugs every other oil change, and check gap. Then adjust as necessary.

Also with the heat you are dealing with, going one step cooler may help your situation greatly.

Ask your tuner (if you are) about their stand on colder plugs.
I dont even bother gapping them anymore, i just keep at least one extra set around.
The plug that broke was one step colder, I had been running them on the car almost exclusively, they are now 2 steps colder. We will see how it goes.
 

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Discussion Starter · #15 ·
Fellow AV owner! Which ST are you? I was at the 2nd to last grudge night (the White ST with the Gold Snowflakes) Let me know if you need a hookup for photogenic stuff :)


Enjoyed the read, and I always keep an extra set of spark plugs, so if you are ever really desperate and all the parts places are closed. I'm local and have a set of Motorcrafts ready :)
I am the Ingot Silver 2013 with red mirror caps and black Advantis in Rosamond. I also have a black Zetec S lower rear valance and single exit driver side exhaust. Chase me down anytime! @jorgenspeed on IG if youre a visual learner ;)
 

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Discussion Starter · #16 ·
You didn't "drop" the electrode in the cylinder, you burned it off...it essentially vaporized, and blew out the exhaust. Detonation is usually the cause. I'd turn the tune down a bit, or next, you'll have chunks of the ring lands blown off. Anytime I've seen a burned plug, I've found other damage as well. You'll most likely at least find fine pitting around the edges of the piston...again, from deto.

You should NOT be eroding plugs. If you are, something is wrong. I know several guys with Escape 2.0s with close to 100k on them, with original plugs. It's not the engine.
And don't use anti-seize on the threads. There is no need. It just goops them up. A light coat of oil is all you need.
Is there a way to tell the difference visually? To me it looks as though it was fractured where the strap meets the body, not melted. I will try to get a picture of it and post it when i can.
I have never had any alarming readings showing up on the AP so i never really thought there was a reason to expect det. but now i want to get a boroscope in there and see!
I am by no means easy on the car so i always just chalked it up to the amount of time i spend "in boost" being harder on plugs. Generally they just basically chamfer the end of the ground strap, causing a .040 gap or so between that and the electrode (which generally doesnt look bad). I know it isn't hard science according to a lot of people, but the insulators also keep the "healthy brown-ness of pretty ideal combustion".

Is there any reason for the problem cylinder to switch, from #1 to #4 like this? Id imagine theyre all having issues to some extent. I have also heard from a few people that Densos are more known for failures like this? I forsook NGK a few sets back because the brass terminal that lives in the coil boot stripped the threads and was making questionable contact at best. I guess of the two, the lesser evil is the cap coming off lol,
 

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Discussion Starter · #17 ·
I haven't removed my OEM spark plugs yet, just hit 16k miles, nervous to do it as I haven't before, previously read how-to/sticky guide, I think it was by Deuce, gotta get spark plug socket, possibly anti-seize. Might as well replace if I'm gonna pull 'em, no?
The way i look at it, yes. Its cheap insurance to throw a fresh set of $40 plugs in if you pull them out anyway. Everyone seems to have a slightly different experience with these cars in that regard, though.
 

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When the motor goes I have a fresh 2.3 in the garage with headwork and cams. I met you once a long time ago at the meet in Palmdale
 
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