Spark plug electrode broke (Repost)
06-20-2005, 12:33 AM
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Spark plug electrode broke (Repost)
Has this happened to anyone? It broke off in the middle of the bend and the remaining electrode stem has a nice clean edge. Definitely not burned away.
It broke off during the last session of the track weekend. I noticed that anytime that I went over 3/4 throttle there was a machine gun type sound and reduced performance (I think). I thought that the sound was explosions in the exhaust but with ear plugs and a helmet, I'm not sure. I've been having trouble with the MAF so I thought that this was another manifestation of that.
The car idled fine when coming into the pits so the spark must have jumped the gap well enough at low RPM. Perhaps at high RPM, it didn't fire and the explosions were the fuel exploding in the exhaust pipe.
Anyway, I did a compression test and compression is the same as a few weeks ago.
A magnet in the cylinder did not produce the offending piece of steel. I ordered a borescope yesterday so that I can inspect the cylinder walls and turbocharger exhaust vanes without removing the turbo. (I consider removing the turbocharger worse than replacing the clutch) If the turbo is OK, then the electrode must be in the crossover pipe -- I HOPE.
Does anyone have related advise / a story / condolances?
It broke off during the last session of the track weekend. I noticed that anytime that I went over 3/4 throttle there was a machine gun type sound and reduced performance (I think). I thought that the sound was explosions in the exhaust but with ear plugs and a helmet, I'm not sure. I've been having trouble with the MAF so I thought that this was another manifestation of that.
The car idled fine when coming into the pits so the spark must have jumped the gap well enough at low RPM. Perhaps at high RPM, it didn't fire and the explosions were the fuel exploding in the exhaust pipe.
Anyway, I did a compression test and compression is the same as a few weeks ago.
A magnet in the cylinder did not produce the offending piece of steel. I ordered a borescope yesterday so that I can inspect the cylinder walls and turbocharger exhaust vanes without removing the turbo. (I consider removing the turbocharger worse than replacing the clutch) If the turbo is OK, then the electrode must be in the crossover pipe -- I HOPE.
Does anyone have related advise / a story / condolances?
06-20-2005, 12:59 AM
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The borescope that I ordered yesterday will arrive on Wednesday and the hot side blades will be the first thing that I check. I dropped the exhaust and have only the short curved outlet pipe attached to the turbo.
06-20-2005, 01:02 AM
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Originally Posted by Claus Groth
A magnet in the cylinder did not produce the offending piece of steel.
If you need, I have Neodynium magnets that I can send you. Neo's are so strong, they'll suck the blood right out of your skin and cause blisters if you're not careful.
06-20-2005, 01:13 AM
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Originally Posted by WolfeMacleod
What kind of magnet did you use?
If you need, I have Neodynium magnets that I can send you. Neo's are so strong, they'll suck the blood right out of your skin and cause blisters if you're not careful.
If you need, I have Neodynium magnets that I can send you. Neo's are so strong, they'll suck the blood right out of your skin and cause blisters if you're not careful.
Thank you for the offer and if the electrode is still in the combustion chamber and I can't retrieve it, I will definitely ask for your help.
06-20-2005, 02:51 AM
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Borescope the cylinder wall, but you're probably fine, you'd be surprised what you can pass through a running engine and turbo without issues.
Sam
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06-20-2005, 04:20 PM
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On my buddy's 944, the spark plug vanished, leaving only the threaded part that screws into the cylinder head behind...... it was bizzare...the rest of it was COMPLETELY missing... have no idea where it went...no dents in the hood, nothin... runs great now that it's got a new plug in there, but still it was just wierd...
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06-20-2005, 05:14 PM
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Hey..what happened to the first post? What kind of plugs were you running? Several folks have seen the electrode fall out of Bosch platinums on this board. I had one fall out on me and it left a lot of nice little nicks on the top of the piston and the cylinder head. No apparent damage to the turbo though.
06-20-2005, 10:04 PM
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Actually I was brain dead at the time. I wrote repost when I meant to write cross-post and Rennlist wouldn't allow me to change it.
I use Bosch silver plugs, WR5DS. I'm hoping that it either went through the wastegate or is resting on the bottom of the cross-under pipe. I'm organizing a search party now to go in with a magnet through the wastegate opening.
I use Bosch silver plugs, WR5DS. I'm hoping that it either went through the wastegate or is resting on the bottom of the cross-under pipe. I'm organizing a search party now to go in with a magnet through the wastegate opening.
