Crazy blown spark plug issue...

hot96cobra

New Member
Jun 1, 2005
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Is it common, semi-common, or insane that I blew a spark plug out of the cylinder? It looks like the guy I purchased my cobra from didn't exactly replace the plugs and wires properly and now I'm in trouble. The threads on the head are stripped, but the plugs threads aren't beat up at all. Just curious if this has happened to anyone else. Also, I don't suppose anyone would have a rough ballpark on what the cost of repair would be? Thanks.
 
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sounds like he had the plug cross threaded...I've heard of it happeneing before with these aluminum heads...usually to fix this a mechanic has to install a helicoil in the plug hole so the plug has something to thread into...usually this fixes things...not sure on the price to do this though...
 
A lot of 5.4L F-150's have had blown plug issues. There is a thing called a "Bigsert" (basically a threaded insert or heilacoil) that a lot of guys have used to fix theirs ($100 insert kit with tool). The alternative is head repair / replacement. Failure for the F-150 guys was attributed to Ford threadding only a portion of the plug holes on the heads of certain vehicles. Threads were on half the hole and the other side was smooth. Good luck. I'm praying my 5.4L F-150 doesn't have that problem when the plug change is due.
 
Well, I appreciate the sympathy and information. My car was repaired pretty much using a helicoil. Obviously, they had to pull the engine and take the head off to do it, but with that and brake and rotor replacement for the rear, it ran me $650. Apparently, the guy who did the work on my car had run into that same problem with an f-150 but charged the guy $3000 to fix.