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07-07-2012, 10:17 PM #1
Does this look typical? (blown plug)
Same old story, had a slight tick...got on the freeway..."WTF!?"...pulled over.
Question being, does this look typical? I was surprised at the amount of thread damage to the plug itself. Any insight would be appreciated.
Of course on the way back an autocrossed-out S2000 and a 2012 SS wanted to play.
And this one shows the strap hammered onto the electrode:
07-07-2012, 10:19 PM #2
check the threads on the head? I would be most concerned about the smashed strap (piston, valve, debris?)
1998 CY Cobra coupe - nearly rusted to the jack stands
07-07-2012, 10:26 PM #3
EDIT: Just got a better look down in the chamber...threads are history and it looks like somebody dumped a bunch of fairy dust down the hole. Assume it's what were once the threads in the cylinder head.
Also, seems to be a lot of oil on the plug and in the combustion chamber. Not gallons...but.
Last edited by T800; 07-08-2012 at 01:58 AM.
07-07-2012, 10:57 PM #4
Does the ECU shut down fuel to that cylinder since there is no coil(spark)?
Reason I ask, can I drive it to the shop Monday or am I asking for trouble?
07-07-2012, 11:33 PM #5
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07-07-2012, 11:56 PM #6
07-07-2012, 11:58 PM #7
I wouldn't even attempt to start it, much less drive it, before i took the heads off to check out the piston. At the least you're gonna have metal shavings in there. I would much rather be replacing a few piston's and rethreading the hole than to be buying a whole new block because you threw a rod out the side after trying to drive it. just my .02
07-08-2012, 12:01 AM #8
This is a big problem with the Lightnings. Yes you can drive it if the distance isn't to far just make sure you disconnect the injector for that cylinder.
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07-08-2012, 12:01 AM #9
You can take one of those extendable magnet pen's and slide it down into the spark plug hole and see how much shavings you can get out, They may be shavings from the plug but I doubt it, I hope you get it all sorted out man!ツ 2003 Redfire Coupe #4319
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07-08-2012, 12:02 AM #10
That sucks hope that doesn't happen to me after my auto x tomorrowCurrent toy black 2014 5.0 M6 brembo package ..... Auto x and road course vehicle eibachr2 coil overs..svedrifts..jba o/r x pipe..aed tune..boss grill..boss diffuser..Laguna seca wing..boss chin splitter..GT500 cans..corbeau seats..hp plus brake pads .. MM caster and camber plates..MM panhard rod ..billet shifter..nitto NT05 ... Watson racing 4 point roll bar .. some more crap on the way
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07-08-2012, 12:16 AM #11
Thanks for the support guys. Right after it happened I drove the car about 10mi on the freeway to get back home. I'm feeling like that piston is toast.
Here's a pic of the piston/"shavings"...best I could do...it's getting dark outside. (sorry about the crappy cell phone pic)
Last edited by T800; 07-08-2012 at 12:20 AM.
07-08-2012, 07:50 AM #12
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Im sure that piston is toast, but now you have to look at saving the rest of them and the block. I would not drive it anymore untill the head is off and you can inspect it good. All it takes is a small peice of that stuff to screw up that cylinder wall and your eating a full set of pistons and a machine shop bill along side the bill from the heads...03 Cobra Vert FOR SALE
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07-08-2012, 09:27 AM #13
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- la grange kentucky
Ring land might've gone with that electrode damage. Had it happen to me before on my gt.2000 BAB GT, Procharged, 4.10's, No Cash Racing built motor, cms stage 2 blower cams, 10 lbs 430 rwhp and 400 rwtq, tuned by lee blankenship
07-08-2012, 09:58 AM #14
Went out this morning.
From what I can tell, that last pic is what the top of the piston looks like now. Tried to wipe off some of what looks like shavings from the head and they don't budge. I'm thinking the credit card is going to get its a$$ kicked come Monday.
07-08-2012, 12:01 PM #15
Piston is done... funny how the cylinder wall doesn't look scored after that, but the speckled areas on the dish look like detonation..
Were you in boost when that happened or just cruising?
07-08-2012, 12:17 PM #16
fix the threads and pump the cylinder. they all look like that when they blow out. My father in law blew one on his v-10 w/ 83k. I took it to work and put a lock n stitch in it, he's been driving it ever since and now has 150k runs great. I'm sure it's fine.
BTW this is so commonplace anymore with 2v and 4v heads. done so many I've lost count, but NEVER had one come back or have a dead cylinder after the fix.
07-08-2012, 12:59 PM #17
The plug looks all banged up from bouncing around in the well.
Get your self a boroscope so you can look in the cylinder / piston before spending any money and pulling anything apart. Once you get a good look in there and feel comfortable with your findings, move on to the next step. You may get off scott free with a new plug and on your way... $2.00 fix. Helicoil if needed.. etc. You need to investigate it some.
Last edited by Blueline; 07-08-2012 at 01:00 PM._________________________________________________
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07-08-2012, 01:25 PM #18
07-08-2012, 04:51 PM #19
07-08-2012, 07:02 PM #20
Can someone explain to me what cause's this?2003 Redfire Cobra. Build date 10-3-2002. #3562 of 8394
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07-08-2012, 08:22 PM #21
not enough thread depth, overtorque, fatigue of the aluminum. Could be any of those reasons. I've repaired heads that have blown out original plugs with 60k on the clock. but Ive also seen replacement plugs blow out... and the plug gets beat up from banging around in the s.p. well just like Blueline said. The 2v motors have a small bolt holding the coil down and there's enough force to break the plastic tab off the side of the coil. And it splits the boot open like a hot dog in the microwave.
07-09-2012, 05:47 AM #22
07-09-2012, 06:16 AM #23
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I would let the cylinder dry out for a while and use a strong vacuum cleaner with a pointed tip to try and such as much of those shavings out as possible.
Typically detention will cause that ground strap to "melt" off. Happened to me once.
Dont drive it, start it, or rotate the engine in any manor. It will only make things worse inside that cylinder.
07-09-2012, 10:52 AM #24
The ticking was a tell-tale indicator and I have read other posts that cited this issue just before losing the plug. I feel that if I had identified the ticking as a leak at the cylinder and not due to exhaust leak or a pulley, etc. I could have torqued it down and been fine. It's just too fine a line with only 4 threads to work with.
I could be wrong...it's happened before, just can't remember when.
07-09-2012, 12:41 PM #25
After calling many of the "performance" shops around here, including one that you locals to my area know of(who by the way pushed to replace the entire head+labor $3-4K). <---no prizes for guessing who THAT was.
Called Ford of Bellevue, service guy knew right off what I was talking about, said they use the LocknStitch aluminum insert. Quoted me $62.50 + cost of the insert itself. Dropping the car off Wednesday @07:30. Will let you guys know how it goes. I will definitely put it to the test!
Thanks for all the advice and good wishes. The community here is top notch.