Broken head bolt...am I screwed?
#1
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I went to reassemble my LS1 after teardown, inspection, and rebuild. Upon torquing the first headbolt on the passenger side to 22 lb ft, the torque wrench I borrowed never popped and I ended up breakint the head bolt down in the block. Tht top of the broken part is @3/4 of the thread on the long bolt, and I cannot reach it will a drill bit. Am I screwed or can I tap the hole out above this to put in a larger bolt?
#3
TECH Junkie
iTrader: (18)
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Here is a place to get long drill bits. They aren't cheap, but it's what you need. I don't know if it's possibet to get a long extractor to use after you drill the bolt.
http://www.mcfeelys.com/standard-extra-long
http://www.mcfeelys.com/standard-extra-long
#5
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I'm just wondering because I cannot get to the existing part and there is a space @ 2" above that that has no thread. I really have no way to get to the existing bolt because I cannot find drill bits, or an ez out long enough.
#7
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I used GM headbolts, and I borrowed my dad's Craftsman 3/8" micrometer adjustable clicker. Apparently it was broke and neither of us realized it. Just as I said it felt like the bolt was past torque, it snapped. I readjusted the wrench for 5 lb ft and tried another bolt, and it never clicked. That was when I realized it was broke. I have a beam torque wrench, and was also wondering if this would be an acceptable one to use?
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#8
TECH Senior Member
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Try a screwdriver and see if the broken piece will just back out. Sometimes if they break and the threaded portion isn't bottomed there won't be much load on the broken bolt and it will back out. A long pick or even a chopstick might work if there is no load on the bolt threads.
#9
11 Second Club
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You must have had both feet on the block pulling that 3/8" torque wrench. I know the ARP headbolt thing will come up but to snap a GM headbolt with a 3/8" torque wrench on the first pass sounds almost impossible. At 22 lb ft, then 90 degrees and 90 degrees for the torque angle spec you put a lot of pull on the bolts. Were the bolts brand new? Are you sure that they were the correct bolts. The are two designs for the headbolts. Perhaps the wrong bolt in the hole? Heck even then you shouldn't be able to break a headbolt with the tools you were using.
#10
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I was just leaning over the side of the car torquing to 22. By actual torque feeling, I thought it was getting too tight. The wrench never clicked, so I just assumed it wasn't tight enough. This is the # 1 M11 bolt right in the middle of the head. Brand New and correct bolts. No water, or debris, or anything else in the hole. I have talked to 4 GM shops in town, and they told me they have had this happen, and it is much easier to just tap the hole out for a bigger bolt. They said that they have had to do this many times.
#12
TECH Addict
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So, GM techs are breaking head bolts off with regularity? Now, isn't that special. Then they just drill out the hole to the next oversize and tap some new threads. Do they bother to inform the customer that they busted off one of their heads bolts. I doubt it. I don't buy it. 22ft/lb isn't a high torque value. You need to have a "feel" for these things as they say. Can't say I'm surprised that this happened because some people are even able to damage or break off the crank pulley bolt. How they manage that I'll never know. You have your dads Craftsman torque wrench and you have your God-given torque wrench. Your wrist is calibrated in in/lbs., your elbow is calibrated in ft/lbs. and your shoulder is calibrated for the crank pulley bolt. When the value on your Craftsman torque wrench exceeds the value of your God-given torque wrench a little lite is supposed to go off in you head that says: "STOP"! You don't need a new torque wrench. You need a new lite bulb.
#13
#14
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I have been trying for 4 hours to remove the existing piece, but it just won't come out. The only result I have had was the extractor spinning in the hole I put in the bolt. Then it got stuck, and I had to screw up the threads to get it out. I am just SOL!!! It won't come out, now I have no good thread to use even if it did. I cannot afford to remove the engine, or tow it anywhere to have this fixed, nor can I afford what it would cost to have it done. Just my luck.
#15
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By the time my lite went off it was a little too late. Something told me it wasn't right, but I trusted the wonderful tools, and they let me down. From what I heard from the dealerships is that when they break headbolts, it is when removing them. They just tap the hole above the broke part and use it. If you look in the hole on the block itself, there is @ 2" before the thread even starts.
#16
TECH Senior Member
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This is the small bolt along the top correct? If so, no choice now but to tap to a larger size. You may need to drill the head as well depending on what thread will fit. Get a diameter on the upper section of the hole and then use that as a minor diameter to see what thread size to use. I am guessing an M10, maybe an M9 if its currently an M8.
#17
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Wow! So these stock bolts are just snapping in the block during removal? Making me think twice about doing my own head install ![Sad](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_sad.gif)
Is there anything preventative during head removal to ensure the bolts will not twist off in the block? Heat gun, torch, lube??
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Is there anything preventative during head removal to ensure the bolts will not twist off in the block? Heat gun, torch, lube??
#20
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Unfortunately this was NOT one of the small bolts. It is the M11 right smack dab in the middle of the head. The only thing I can think of is to tap the hole, but the next size up is 1/2"