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URGENT! Damaged threads on head

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Old 11-25-2007, 02:51 PM
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Default URGENT! Damaged threads on head

I've removed my cheap O'reilly header gaskets and I'm installing new copper ones. I was foolish enough to leave the Y-pipe attached and try to put the header back on this way. In the process I had two bolts (far outside) holding the header up in place while I slid the gasket in. The weight from the y-pipe pulled the bolt out and I'm not sure if this damaged the threads or if in the process of trying again I managed to cross-thread it. Either way the bolt will go in but it's definitely damaged and would have to be forced to continue all the way through. I have the aluminum LT1 heads from '97 and I'm looking for some other opinions on what to do.

A) Force the bolt in and hope it doesn't get too hard to push farther before it's completely snug
B) Chase the threads with a tap

If I use a tap I'm going to have to do it with a wrench because I can't fit a drill in there and the head is definitely not coming off. Is there some sort of thread chaser I can pick up that I don't know about?
Old 11-25-2007, 04:17 PM
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you might want to look into helicoils. it'll make the threads stronger than they were originally. you'd first have to drill out the old threads, tap new ones in, and then insert the coil. Check it out. you should be able to get them locally.
Old 11-25-2007, 07:06 PM
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chase the threads with a tap if it is only the first couple that is crossed. If it is bad, use the helicoil. They work great.
Old 11-25-2007, 07:53 PM
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You don't need a drill to tap the threads. But you do need a drill to helicoil. If it has to be helicoiled then you will have to pull the heads. Most likely you can tap it
Old 11-25-2007, 07:59 PM
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How far in did the bolts go? If it was just a few threads, chase 'em with a tap to clean 'em up. Otherwise, you might have a project on your hands...
Old 11-25-2007, 08:00 PM
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moving to internal.
Old 11-25-2007, 08:04 PM
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chase the threads, it's your only choice if you want to avoid pulling the heads.

Re'
Old 11-26-2007, 01:51 AM
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I doubt the y-pipe exerted TOO much force on the bolts (unless the header was at some jacked up angle or something), so I would think a tap/chaser would work fine with a patient operator.
Old 11-26-2007, 02:35 AM
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There's nothing wrong with the method you used, but you can't just screw the bolt in one or two threads and expect it to hold that much weight. If you only turned the bolt in a couple of turns you might get lucky if you follow the instructions you've already been given. That's a common metric thread. Next time screw that bolt in more than just finger tight. Short cuts don't always save time. This is a case in point.




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