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Re: broken head bolt

To: curt1@ix.netcom.com, mgs@autox.team.net, jtilton@vt.edu
Subject: Re: broken head bolt
From: jurrasm@genesis.torrco.com (Mark Jurras)
Date: Tue, 23 Apr 1996 08:09:31 -0400
> 
> Curtis wrote:
> >Then it happened...SNAP. I broke off one of my head bolts in 
> >the block. It was one of the long ones that hold the rocker arm 
> >on as well. Help! How do I get the broken bolt out of the head?

I had the pleasure of a broken head bolt on my 1980 Olds Cutlass 5.7L
diesel engine. It was grade 9 (as hard as the drill bit for the easy
out). I got the remains of the bolt out in less than 2 minutes by
taking a pointed tool putting it near the top edge of the broken bolt
and tapping with a hammer. After turning the bolt a couple of
revolutions I could grab it with my fingers and twist it out.

                                      ________ Pointy tool  
                     /----------\    /
                    /     <======\==========  <<Tap     
                    |            |
                    |            |
                    |            |
                    \            / <--Pretend this is round
                     \__________/




> Jay Tilton  wrote:
> 
> But I'm wondering if anybody knows if a head bolt that snaps during torquing
> might cause any big problems.  I'm envisioning a scenario where the sudden
> localized loss of clamping force would cause the head to warp or crack.  Or
> would that only happen if the engine were allowed to run in such a state?

Fear not, a broken bolt during torquing won't damage the head. Warping
is caused mainly by overheating. Flatness is critical to get a good
seal with the head gasket.

Professional engine builders always use new head bolts and rocker arm
bolts when they rebuild engines. I didn't when I did my Pontiac 326
engine. Never had a problem.

- -Mark   = =o&o

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