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head bolt help!
Posted: June 2nd, 2012, 11:27 am
by EVIL95XJ
i ordered a set of head bolts from headbolt.com, i ordered the 86-96 set, they are not the same as the stockers i pulled from my 95`s head, they are 7/16" thread
whats the issue here? are the 97-up 7/16"?
Re: head bolt help!
Posted: June 2nd, 2012, 11:36 am
by IH 392
As far as I'm aware ALL of the 4.0's are 1/2" head bolts, only a few years span of the 258's were 7/16" , seem to have misplaced my torque spec manual to see what was what?
What was wrong with the OE head bolts??
Re: head bolt help!
Posted: June 2nd, 2012, 11:49 am
by EVIL95XJ
ill have to double check
i was told i needed to replace them and for 30-40 bucks its not a big deal
Re: head bolt help!
Posted: June 2nd, 2012, 2:28 pm
by EVIL95XJ
double checked, my buddy used the sizer and told me they were 7/16", they are 1/2" tho thanks
Re: head bolt help!
Posted: June 2nd, 2012, 5:21 pm
by IH 392
EVIL95XJ wrote:i was told i needed to replace them and for 30-40 bucks its not a big deal
Who told you that?, the AMC/Jeep engines NEVER! used "torque to yield" bolts, I have yet to replace ANY! head bolt in any engine that I've built that didn't have "torque to yield" bolts in it.

Re: head bolt help!
Posted: June 2nd, 2012, 7:26 pm
by Muad'Dib
They are a variant of TTY... they can only be re-used once. Its cheap insurance to replace them. Technically when they are re-used they will have a paint mark on the top of them (this is assuming the person who re-used them painted the heads).
Re: head bolt help!
Posted: June 2nd, 2012, 10:16 pm
by IH 392
Engines that use Torque to yield bolts have them included in the new gasket kit, they also use some degree of rotation after a puny little seating torque is applied, for example, Ford Escorts, NEW bolts torque to 44ftlbs, turn 90*, turn 90*, done several of them!
Re: head bolt help!
Posted: June 3rd, 2012, 9:04 am
by EVIL95XJ
Muad'Dib wrote:They are a variant of TTY... they can only be re-used once. Its cheap insurance to replace them. Technically when they are re-used they will have a paint mark on the top of them (this is assuming the person who re-used them painted the heads).
this is what i was told, thanks
Re: head bolt help!
Posted: June 3rd, 2012, 12:08 pm
by Muad'Dib
This is per all Jeep year FSM's... if you cant trust that what can you trust

Re: head bolt help!
Posted: June 3rd, 2012, 3:14 pm
by EVIL95XJ
Muad'Dib wrote:This is per all Jeep year FSM's... if you cant trust that what can you trust

exactly, i love mine
Re: head bolt help!
Posted: June 3rd, 2012, 5:31 pm
by SilverXJ
At one point in my various builds I had two or three head bolts fail upon final torque. They hour glassed. Using a torque wrench that was recently calibrated. The bolts may have been used 3 or 4 times. They just didn't feel right when pulling them to the final 110. Sort of spongy/soft.
Re: head bolt help!
Posted: June 3rd, 2012, 5:35 pm
by SilverXJ
Muad'Dib wrote:This is per all Jeep year FSM's... if you cant trust that what can you trust

On the 2000 XJ the fuse panel door told you to look in the manual for the fuse info, the manual told you to look on the panel door. This is the same company. LOL