Pics of the spark plug damage (opinions please)?

[paulviriyapan]

Okay guys, for those of you who have been following my 'engine problems' I've attached some pics, and would love to hear some opinions. Unfortunately the Acura dealer hasn't finished putting the car back together (and once it is done it is going to Ramon at Niguel Motors for the work) so I don't have the car with me to take engine photos. I managed to grab the coil and the remains of the spark plug, and am attaching photos.

Long story short, looks like somehow the spark plug came into contact with something in the cylinder, either the piston, or perhaps the valve, or potentially some debris in the cylinder. The impact pushed up the spark plug into the fuel coil (pictured above the spark plug remains) and pretty much shattered the coil(!).

I believe there can be only three potential theories for this damage:
1) the piston came up too high and hit the spark plug
2) the timing was off and somehow the piston came into contact with the valve which rammed into the spark plug
or
3) (and my personal favorite theory as it is the least expensive fix), the threads on the head securing the spark plug stripped somehow (perhaps the spark was overtightened stripping the threads, someone changed the spark while the engine was still hot and the aluminum was still soft, etc.) .As a result of the stripped threads, the plug got sucked down into the piston and pushed up into the coil (like a cork popping out of a champagne bottle).

These are the facts as we know it:
1) We (tech and myself) removed the oil pan (and everything else whose technical names escape me) and the bottom end is okay. There is no damage to the crank, the connecting rods, bearings, etc. Hence, we don't think that the piston came up too high (negating theory #1)
2) We drained the pan and sifted the all the oil through a sifter and there was absolutely no debris. Thus we believe that the valves are probably o.k., as if there was any valve/piston contact, there would have been some metal in the oil.

I would very much like to hear any other opinions out there as to what potentially could have happened and what I should check. Thanks alot.

 

[paulviriyapan]

pic

 

[paulviriyapan]

Another pic (notice that the end towards the spark is bent in, like a cone shape almost).

 

[paulviriyapan]

Spark plug and coil.

 

[Daria]

Where you driving as this occured?
If so, what rpm range were you in?
Did you hear any noises?
Did the engine stall - or it continued running?

 

[paulviriyapan]

Well, the 'incident' ocurred Tuesday of last week. I had driven the car on Monday with no signs of problems. On Tuesday, when I started it up in the morning, she started sputtering a bit and backfiring a bit. If you've ever had a car that need a valve job/valve adjustment and wasn't idling properly, it seemd like that. She seemed to run fine when I gave it some gas.

I decided to take it to the acura dealer about a mile from my work. As soon as I hit the freeway (just entered it for about fifty feet), there was some major backfiring going on and I could smell smoke/fuel. I immediately pulled off to the side, and could hear that the engine was definately not firing on all cylinders and was running extremely rough. This is rush hour traffic in Orange county and I didn't want to wait for a tow truck so I then drove it to the dealer (about 7 miles away).

When the dealer tech pulled the valve covers, he noticed the fuel coil was shattered and the spark plug was bent (the part protruding from the engine was like at 30 degrees). They pulled the spark plug (I guess they threw away the large part of it away).

Anyways, when they managed to get the entire spark plug out, what you see is what they found. They had to pull the spark plug out in chunks, but they got all of it out. Unfortunately, the thread inside the head is now stripped.

My RPM's, given the way that the car was running that morning, I made sure to shift at around 3k rpm's, and for sure I did not go above 4k. Even when I got to the dealer the engine was running (didn't die), though it was running rough.

 

[coolnsx]

Why is the car being put back together, how far was it taken down? Has the head been pulled? I would want to look inside to see what happened. Timing belt checked? Lots of questions, sorry I don't have answers without evidence.

 

[paulviriyapan]

Understood. Unfortunately there isn't too much evidence to go off of at this point.

The reason it is being put back, is because I am having Ramon at Niguel Motors do the work. The dealer wanted OVER $2k just to yank the engine (no other work or repair; $2k is just to pull the engine which they said would take 35 hrs of time!!). Ramon quoted me a price of around $800 to $1k to pull the motor and put it back. He's Acura trained, owns an NSX and is the guy the Orange County NSX guys go to. From his previous work on my car I KNOW he does a good job. If it weren't for the fact that he was quite a distance away from where I was at, I would have gone to him first (unfortunately I'm in Anaheim and he is in Laguna Hills).

Yeah, of course I would like to pull the heads to see exactly what the hell happened in there. Unfortunately, to pull the head, you gotta pull the engine because it is really tight back there. Someone else informed me that you could pull the heads and leave the engine in. I will leave the ultimate call as to how to proceed up to Ramon. I'm not a mechanic, and he certainly knows a hell of a lot more than me.

Right now, I'm trying to see if I can get any opinions based on the information that I have. I'm hoping someone may have an idea before we go through the hassle of pulling the motor (hopefully there is something I can check before I pull it).

We did check the timing belt, and it is good. It was replaced about a year and a half ago (previous owner), and the techs said it look in good shape, and they could find no missing teeth. Other than that, I have no idea what is going on in there.

 

[kpond]

The symptoms you describe leading up to the failure would indicate that you had some rather significant timing issues... which ultimately led to a scenario when you had contact with the sparkplug. Sorry, but I think you have more internal damage at least in that cylinder if not others as well.

Reality is that something contacted that sparkplug and it wasn't the piston.

My guess is that you had a significant timing belt slippage or failure. Your scenario #2 is the right one. No way your spark plug got "sucked in"...

 

[paulviriyapan]

That IS what I am afraid of. The potential range of damage is (from the low end) that I just need the head rethreaded to I may have piston damage (which would be the worst case scenario). If the valve did hit the spark, that I suppose would be the middle ground. I talked to Comptech, and they quoted me a price of $500 plus parts (valves @ $28 a piece) to rebuild the head, provided I remove it and send it to them (and that the core is rebuildable).

To put it in perspective, the Acura dealer quoted me the following prices:
$30k for engine
$5k for new heads
$900 per piston.

At this point, I'm hoping the damage is confined.

 

[autobody tech]

Has anyone acess to a type of bore scope?

 

[paulviriyapan]

Hey buddy,

So you got the rest of the rims today? I'm just dying here 'coz I've been waiting all this time, and now I don't have a car to put 'em on to. I suppose that is the least of my problems, eh?

As for the borescope, Weir Canyon Acura (dealer the car is at) doesn't have one. South Coast Acura does. I was going to have it towed there so they could scope it. Unfortunately, the car is still in bits and pieces at Weir Canyon. Ramon told me not to bother and just ship it to him. Either way, can't do anything until they put everything back so it can be flatbedded.

 

[coolnsx]

I think you made the right call going to Ramon, without a doubt he is top notch. Good luck and keep us posted.

 

[autobody tech]

did you buy the engine from Andrie Hartano

 

[paulviriyapan]

Well I wanted to wait until Ramon could take a good look at it. Hopefully, I don't need a new engine (this is what I am hoping for at the moment). If I could get away with a head rebuild, that would be significantly cheaper. BTW Comptech quoted me a price of $6,000 for an engine rebuild (could be more if there is more damage).

 

[PoohBEAR]

paul,
i am sorry to hear what is happening to you. Ramon told me about it today and it is just a sad sad sad story--i guess it can happen to any of us. have no fear, ramon is here . he worked on my last car and so is the car i am having now--it is in top condition. i am sure he can make her run as good a gain without emptying your pocket. the question is, how did it happened?

 

[autobody tech]

Well,i think this Ramon sounds like a good guy ,it seems to me that you are facing obvious internal damage.might as well get it pulled ,fix it,and get back on the road.

 

[ScienceofSpeed]

Check out the piston face and bore with a scope as autobodytech suggests and check how the cylinder holds pressure.

Cheers,
-- Chris

 

[spyderman33]

how many miles on the car?

was timing belt done?

 

[Andrie Hartanto]

did you buy the engine from Andrie Hartano

No he did not.

 

[Gerry Johnson]

here is a thought, when the spark plugs were installed the one plug was not tightened all the way, when installing the coil it was tightened and broke off because off the plug being left loose, after some miles the plug loosened all the way out of the head bouncing on the tip closing the gap and causing the misfire. There is no way that a valve or piston could have hit the plug to do that kind of damage. Check the leakdown on the hole, if it is OK install a new plug and coil and enjoy your car.

 

[Briank]

From looking at the pictures it just looks like the plug just came loose for what ever reason. With the violent in and out movement caused my the normal air movement in the cylinder it stripped the threads, hammered the coil and closed the gap as it banged back in forth. Fix the threads and install a new coil and plug and you should be good to go. I think the threads can be repaired with the head on and the engine in the car.

 

[paulviriyapan]

Thanks Brian and Gerry (who I also thank for emailing me)! Hopefully it is just the threads that went bad. I shudder to think what else it could be if it weren't the threads. I certainly will post more updates on the board as I get more info. Thanks again everyone for the help.

 

[(NSX REY)]

paulviriyapan

I am not in the same situation as you, but I had an abnormal sound coming from my engine. I didn't think much about it and assumed it may need a serious valve job, or at least that’s what I told myself…(Denial) Hoping it wasn’t the bottom end.

When I drove up to our monthly meeting D’Ecosse approached me and said your car didn’t sound good. Knowing fine and well something was wrong, this reaffirmed my gut feeling. The following week was the first day of NSXPO registration so I drove the NSX there to register and hopefully have someone else diagnose the mystery sound. Remember I am still in denial!

No more than 5 minutes of pulling into the parking lot, I see MB and asked him if he could take a look at my car. MB looked busy, but still came over to listen to and test-drive my car (Thanks MB). His first words were…”Not Good”. He went on to say that it sounds like a bad Bearing and without opening her up we wouldn’t know the extent of the damage. He told me to drive home very gingerly and park it, until I can get it in the shop. I did so and drove my other car to NSXPO the whole week. Bummer!!!

To make a long story short, I very recently drove my car to Gerry Johnson’s shop and within Minutes (literally) he narrowed the troubled area down to #2 piston which could involve a bad piston/rod, bearing, damaged crank…? He will call me when he opens the motor up with a definitive diagnosis.

Hanging out at the shop with Gerry, D’Ecosse (Ken) and Gary W. was a blast! I watched how meticulous Gerry was when working on the NSX and would never think of bringing my NSX to another Mechanic. His knowledge is vast; skills top notch and the NSX’s coming out of his shop LIGHTNING FAST!!! (Look out)

Paulviriyapan, take Gerry’s advice and you may save some big $$$. Have your mechanic perform the test Gerry recommends and go from there. Best of luck and I hope your problems are easily fixed.

 

[hlweyl]

I wouldn't buy the theory of the spark plug coming in contact with a piston or valve. The threads on the plug do not look good in the pics you attached... one would have to assume the threads were damaged on install.

Here's two other theories: if the mechanic damaged the threads on install, then he could of been careless and installed a plug with an incorrect gap. How do we know the gap in the plug was perfect at install?

Another theory: timing is way off causing detonation in that cylinder muffing up the plug. Bad detonation can blow a hole in the top of a piston... no reason it couldn't damage a plug.

good luck