Look at my spark plug - How bad is it? (answer: very bad.)
 

I was driving down the freeway when a huge white cloud came out of the tailpipe and the car died. Pulled spark plug number 3 and it looks chewed up. What could've caused this? I don't think I was boosting at the either.

http://i303.photobucket.com/albums/n...a/DSC02177.jpg

holy crap. dont know what caused it, but that spark plug is DONE lol.

Time for a compression test.

Also might not hurt to bring the crank around so that #3 is at TDC and have a look down the plug hole with your eyeball and a tiny flashlight. Make sure nothing funky happened to the piston.

That sort of destruction kinda suggests FOD.

http://img.villagephotos.com/p/2004-.../holy_shit.jpg


+1 for sure! How this happened on a non-interference motor will be interesting....must have been det...

I would not do a compression test yet, first clean out that cylinder...
White smoke is coolant, so my guess is detonation killed your plug and head gasket.

lol

White cloud could have been all the fuel that you Didn't burn in that cylinder getting dumped down the exhaust.

Honestly though do you neglect your motor that bad and not check your plugs every once and a while? That's brutal.

Thats not normal? All 4 of mine look like that when I change them...

Lol

That looks like physical contact.

Possibilities include:

1- a small screw (check the throttle body butterfly screws)
2- dropped a valve
3- piston came apart

I don't suppose you have tried to turn it over since then have you? I'm going to guess its not going to sound good when you do.

oh the carnage! :ohnoes:

hope everything is okie.

Gonna tear the head off on my next day off. The engine's rebuild with only 9k miles. Looks like something made contact with it. I'll take more pics for you guy's entertainment. :P The engine was running great before this happened. Just passed smog with flying colors a week before and a oil change 1k miles ago.

You are not that same guy on m.n that was going to try increasing compression by gluing spare change onto the top of the piston are you? :giggle:

That spark plug is seriously trashed; I've never seen one that bad myself. Sorry it happened. It is hard to tell from the picture but is the deformation from impact, or from melting? Probably not melting, just wondering.

http://i303.photobucket.com/albums/n...a/DSC02192.jpg
http://i303.photobucket.com/albums/n...a/DSC02178.jpg

No, I'm the the same guy. That guy's smoking crack.
Here's a couple of other shots. Looks like impact to me.
There's a sharp cut on the edge, the ceramic in the middle is gone and electrode is bent at 90*. The ground electrode is smashed against the edge and possibly melted.

Looks like it melted to me. Clogged injector and reeeeealy fucking lean maybe?

Hopefully just melted. Because if something made contact with it I'd hate to see what it did to my cylinder walls. I'll try to find out by tuesday.

I wonder what the chances are of a spark plug breaking under combustion. Looks like the electrode is broken off way down inside. Don't think an electrode would have been able to bash the end of the plug to that though. Just a thought.

wow, I was just about to come in here and post a picture of a completely carb encrusted spark plug from my old motor but that's just a little more impressive...

That plug is fucked. In the ass. Hard.

Kabluey!

All of the pieces that are missing form that spark plug are either embedded in your piston, still in the combustion chamber, or went through your turbine. Oh, that sucks so bad. Oh, so bad...

Maybe if it is foreign object damage you'll still have a piece or two of it in there somewhere. Hmmm... will you find the nut off ZX-Tex's compressor in there?

Here's an update. Motor's died and gone to heaven. :(
Somehow two of the valves broken along with a fat hole in the piston.
The caused havoc on the head and piston but the wall seems alright. Slight scratch but I think a little boring and it'll be fine.

#3 valves
http://i303.photobucket.com/albums/n...a/DSC02195.jpg
Attachment 205313

Head
http://i303.photobucket.com/albums/n...a/DSC02196.jpg
Attachment 205314

Block
http://i303.photobucket.com/albums/n...a/DSC02199.jpg
Attachment 205315

Close up
http://i303.photobucket.com/albums/n...a/DSC02202.jpg
Attachment 205316

Closer still
http://i303.photobucket.com/albums/n...a/DSC02201.jpg
Attachment 205317

#3 Cylinder wall
http://i303.photobucket.com/albums/n...a/DSC02203.jpg
Attachment 205318

Needs more [ i m g ] ... [ / i m g ]

Wow, that is some serious engine carnage. Looking at #2, your engine saw some serious detonation and then the #3 spark plug exploded and tore down #3 with it.

Well FUCK ME! That would do it wouldn't it. I guess the mystery is over. Sucks to see it man, hope you get it rebuilt and back on the road. I would like to know what triggered it. Was it piston killing valves, or was it valves killing piston.

Spooky: What makes you think #2 had detonation? The shiny metal debris around the piston, I believe, is from #3.

What sux is my Camaro broke down on me as well.
Gonna be a little bit before miata is back in action.
Not sure if i want a quick fix and take my friend's used motor or if I want to get oversized pisons for a rebuild. Think the crank and rods are still good?

Ok, then I don't know. I thought it looked like pitting in that cyl. But if it's just debry from #3 forget what I said.
Crank yes probably, rods you want to forge anyway if you're doing it right. Otherwise just take your friend's engine. Do both in fact: dump that engine in and drive while you take your time to rebuild this one. You want to rebuild exactly once.

Do not reuse that rod. It spent quite a few revolutions trying to press those broken valves into your cylinder head with all its might.

Holy crap that is impressive carnage. Wow...

I agree your crank is probably OK but have a machine shop check it out. No way I would reuse that rod either, and I recommend upgrading to forged rods as well if you are going to rebuild a motor.

:bowrofl: Yeah and if you find it I want it back too, damn it!

now fess up. what did you do.

That is AWESOME. Good job. (sorry to hear about your car)

I'd like some details as to the engine management, the turbo setup, and what sort of operating conditions this engine had been exposed to in the days and hours leading up to the failure. IOW- over-boost, over-rev, etc.

From the pictures, it almost seems like one of the two intake valves might have been the first thing to go- probably the one closest to the #2 cylinder. I can't say that I've ever seen an intake valve spontaneously fail, but if I were doing a failure analysis and event recreation, I'd be biased to presuppose that one of the valves failed at the stem and fell down into the swept area, where it was driven up by the piston during the subsequent compression and exhaust cycles, impacting the adjacent intake valve and causing it to deform and break such that it became lodged in the port.

Were any pieces of foreign matter (such as a nut or screw) found either downstream in the exhaust system or in the oil pan?

I still think the turbine is probably hammered, too. That is a lot of garbage to go through it at 100k rpms.

Judging by the pistons/head on each other cylinder....i'd say it detonated just a little a bit.


http://www.threadbombing.com/data/media/3/gangcar.jpg


Now to reiterate: what did you do?

http://boostedmiata.com/random/detonate.jpg


you had detonation on all cylinders.

Look at the valve keepers, you might have dropped a valve.

I have to say that even though these are two piece valves, breaking them in two in that fashion is not the norm! They usually just bend.

I was honestly cruising to work. Went to a store to get a snack on the way to work. Hopped on the freeway and a quarter mile in it blew up on me. I wasn't even boosting which has me mystified. If I was boosting at least I could say I deserved it.

I'm actually running a M45 supercharger with a smaller pulley. 8psi max.
Bipes + powercard.
E-manage blue still new sitting on work bench :(

No foreign matter found yet. Just pulled the head. Probably not going to pull the rest until I decide what to do.

Let me guess. You don't have a wideband either so you don't know just how lean you were running.

Is that a good guess?

It likely that whatever caused this happened some time before the actual failure occurred.

mrtonyg raises a hugely valid point- It will be interesting to closely examine the valve keepers and their mating point on the stems for the two intake valves which have been destroyed, to see if there is any evidence that the keeper came loose and allowed the valve to fall into the swept area.

Should've used 2 powercards.

ARP studs and a powercard, eh?

Good for you.
I like the pic of the old head in the other thread.