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headbolt torque question

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Old Aug 12, 2011 | 11:58 PM
  #1  
kennebellgt's Avatar
kennebellgt
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Red face headbolt torque question

Mods in signature, I just installed new head gaskets and I torqued my head bolts down to 80/80. Do you think this will be ok? I understand now that it was supposed to go 70/80 but everything in almost done, lmk what you think,

Thanks

Edit: I used arp head bolts (new)

Last edited by kennebellgt; Aug 13, 2011 at 12:15 AM.
Old Aug 13, 2011 | 12:34 AM
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67mustang302
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Did you follow the torque sequence?
Old Aug 13, 2011 | 12:05 PM
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Yes, I made sure of that, I went by the chiltons manual head bolt tightening sequence and went 20-40-60 and final to 80lbs
Old Aug 13, 2011 | 01:43 PM
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It's probably ok. The reality is that torque is a really inaccurate way of controlling bolt stretch. If you torqued it to 80, that means it's probably somewhere between an actual 70-90lbs, depending on how accurate your torque wrench is, what you used for thread lube etc.
Old Aug 13, 2011 | 01:52 PM
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yeah I used arp lube and sealer, I just hope its okay being that my upper bolt are supposed to be higher than the bottoms.
Old Aug 13, 2011 | 09:01 PM
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I've run them the same way as you have yours. Never had anything bad happen yet.
I no longer run them that way however.....
Old Aug 13, 2011 | 11:36 PM
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I run 85 top and 80 bottom, expecially if you are running a poweradder such as myself
Old Aug 13, 2011 | 11:46 PM
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I tried to go 85 for the uppers but my torque wrench wouldn't let me go the extra 5lbs just kept clicking.
Old Aug 13, 2011 | 11:48 PM
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you need a new torque wrench then, throw that POS away.
Old Aug 14, 2011 | 11:34 AM
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It depends. If you torque something to 80lbs, then try to torque to 85, the breaking torque to get the bolt rotating once it was set at 80, may be as high as 90-100 to get rotation started. Sometimes more. You have to overcome the friction of the threads, bolt head etc etc, and it takes more torque to start turning than to actually turn it.

That's also why I lube the underside of the bolt head, washers etc. Anywhere there's contact there's friction.



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