Broken Header Bolt
Melting Slicks
Joined: Jan 2000
Posts: 3,326
Likes: 523
From: home
More than likely the bolt did not bottom out in the cylinder head but the bolt head bottomed out on the header flange. That's the good news. Remove the header and gasket. Get a very sharp, small chisel. The broken bolt will not be a clean, smooth break but have a raised edge to it. Stick the corner of the chisel against this raised part of the bolt and tap the chisel with a hammer trying to get the bolt to turn out. It should come out without any trouble. FWIW, I wouldn't use a 1/2" drive torque wrench for such a low torque spec. If you don't pay very close attention, you may not feel or hear the click and when it does breakaway, it's usually the bolt breaking.
Mark
Mark
Thread Starter
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
More than likely the bolt did not bottom out in the cylinder head but the bolt head bottomed out on the header flange. That's the good news. Remove the header and gasket. Get a very sharp, small chisel. The broken bolt will not be a clean, smooth break but have a raised edge to it. Stick the corner of the chisel against this raised part of the bolt and tap the chisel with a hammer trying to get the bolt to turn out. It should come out without any trouble. FWIW, I wouldn't use a 1/2" drive torque wrench for such a low torque spec. If you don't pay very close attention, you may not feel or hear the click and when it does breakaway, it's usually the bolt breaking.
Mark
Mark
That sucker broke just like you describe.
Only problem is that it has edges at 9:00 and 3:00 with the arc of the curve at 12:00. In other words imagine an O. Cut it in half horizontally. The top half is whats showing. I can get a small chisel on it. But I can't get a swing with my hammer in those upside down positions.
I have tried a small, upholstery type hammer too.
Also, there is very little sticking out. About 1 to 1.5 threads.
Tried to use a broken bolt extractor on it yesterday but it wouldn't grab with the smallest one we had. Not enough of it sticking out. There might be a smaller one though.
I think I'm looking at having it drilled out.
Last edited by '06 Quicksilver Z06; Mar 25, 2007 at 07:51 PM.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Melting Slicks
Joined: Jan 2000
Posts: 3,326
Likes: 523
From: home
The stock bolts have really nothing to do with it. I re-use stock bolts over and over again. I may change the engine in the same car three times a season and have no issues with the bolts breaking. I wire wheel all the sealant that's on them and use antisieze. The bolts don't break at 22 ft lbs of torque.
Mark
Mark
Burning Brakes
Joined: May 2006
Posts: 878
Likes: 0
From: Santa Clara CA
There was a thread on LS1 tech not too long ago about when you add grease or anti-sieze to a bolt you are actually changing the perceived torque. I.e. a greased bolt will be at significantly higher torque than a "dry" bolt at the same reading on the torque wrench.
Anyone heard similar?
Anyone heard similar?
Racer
Joined: Mar 2006
Posts: 324
Likes: 0
From: Kalispell Montana
There was a thread on LS1 tech not too long ago about when you add grease or anti-sieze to a bolt you are actually changing the perceived torque. I.e. a greased bolt will be at significantly higher torque than a "dry" bolt at the same reading on the torque wrench.
Anyone heard similar?
Anyone heard similar?
Team Owner
Joined: Feb 2000
Posts: 45,428
Likes: 892
From: Texas
CI 1-4-5-8-9-10 Vet
St. Jude Donor '03 thru '10, '17
There was a thread on LS1 tech not too long ago about when you add grease or anti-sieze to a bolt you are actually changing the perceived torque. I.e. a greased bolt will be at significantly higher torque than a "dry" bolt at the same reading on the torque wrench.
Anyone heard similar?
Anyone heard similar?
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Safety Car
Joined: Jun 2004
Posts: 4,430
Likes: 81
From: Whidbey Island WA
Is there enough left of it sticking out to cut a slot in that you can use to turn it out? Another method is to weld a suitable bolt up to the end and use that to turn it out. Easier and less risky than you might think when done correctly.
Thread Starter
Team Owner
Joined: Aug 2003
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http://forums.corvetteforum.com/show....php?t=1660507
