Headbolt Torque Specs? 93 3.0L
03-04-2009, 09:11 AM
#2
title changed. Please refrain from titles simply saying "please help"
IIRC, torque spec on the 3.0l goes like this: Step one torque all to 33ft/lbs. Step 2 turn all 90 degrees. step 3 turn all90 degrees
IIRC, torque spec on the 3.0l goes like this: Step one torque all to 33ft/lbs. Step 2 turn all 90 degrees. step 3 turn all90 degrees
Last edited by DeathCougar; 03-04-2009 at 09:22 AM.
03-04-2009, 12:02 PM
#3
Contributing Member
Try looking in the 93 FSM: http://personal.utulsa.edu/~nathan-b...fsm/index.html
Take a little extra time and do EB's special torquing proceedure too.
EB's special head bolt torquing proceedure
Quoted from EB:
Take a little extra time and do EB's special torquing proceedure too.
EB's special head bolt torquing proceedure
Quoted from EB:
>>>*Morning!
*Quite a discussion. We always replace the head bolts on the 3VZE, mostly because of early on we had two cases of breaking them. This spoils a day quickly...
*Ever notice it is nearly always either the last one or the next to last one?...*LOL**
I personally won't make the studs, I do not own the equipment to roll the threads during the forming process. Sure, I could set up and cut the threads, this is much weaker than a formed and rolled out piece. *More work, too and I'm lazy.......All it takes is one little stress riser and the stud can break.
Usually breakage with bolts is due to the threads creating resistance, they stop turning. The same can happen with a stud if the nut end threads are not completely free and lubed. Once they stop slipping as they are torqued, you are now twisting the shaft of the piece. I have had a couple of cases of folks breaking brand new bolts, this is the cause of that.
If the shaft of the fastner is actually twisted rather than tightened into the block, it is not creating clamping force at all, even though the torque wrench may read accurate load.
Yep, it can break. So before we even think of going to maximum torque, we clean the threads in the block with a chaser, (NOT a tap)..Then we oil the threads and spin the bolt all the way in and out with our fingers. This assures they are clean and lubed.
Then we pull them to 50%, all of them. ... back off 1/4 turn and repeat, note each time it will turn a tad more before 50% is reached. This is because the threads are bedding in. We do this 5 times, then we go to 75%, then to 100%, all done. We do this with ALL new fastners...it assures a more even clamping force, inconsistant clamping force is the number 2 cause of early head gasket failure..(heat is number one)
It takes some time, sure, but it takes less time than pulling the head back off...Hope this helps.....*EB
*Quite a discussion. We always replace the head bolts on the 3VZE, mostly because of early on we had two cases of breaking them. This spoils a day quickly...
*Ever notice it is nearly always either the last one or the next to last one?...*LOL**
I personally won't make the studs, I do not own the equipment to roll the threads during the forming process. Sure, I could set up and cut the threads, this is much weaker than a formed and rolled out piece. *More work, too and I'm lazy.......All it takes is one little stress riser and the stud can break.
Usually breakage with bolts is due to the threads creating resistance, they stop turning. The same can happen with a stud if the nut end threads are not completely free and lubed. Once they stop slipping as they are torqued, you are now twisting the shaft of the piece. I have had a couple of cases of folks breaking brand new bolts, this is the cause of that.
If the shaft of the fastner is actually twisted rather than tightened into the block, it is not creating clamping force at all, even though the torque wrench may read accurate load.
Yep, it can break. So before we even think of going to maximum torque, we clean the threads in the block with a chaser, (NOT a tap)..Then we oil the threads and spin the bolt all the way in and out with our fingers. This assures they are clean and lubed.
Then we pull them to 50%, all of them. ... back off 1/4 turn and repeat, note each time it will turn a tad more before 50% is reached. This is because the threads are bedding in. We do this 5 times, then we go to 75%, then to 100%, all done. We do this with ALL new fastners...it assures a more even clamping force, inconsistant clamping force is the number 2 cause of early head gasket failure..(heat is number one)
It takes some time, sure, but it takes less time than pulling the head back off...Hope this helps.....*EB
Last edited by mt_goat; 03-04-2009 at 12:08 PM.
03-04-2009, 12:10 PM
#4
Registered User
The bolts are torque to yield bolts. You must replace the bolts, do not reuse the old bolts. This is due to the fact that the bolts were permanently elongated during the torque procedure when they were first installed. They went from the elastic region of the stress/strain curve to the plastic region.
The intent of torque to yield bolts is to ensure even and accurate clamping by all of the head bolts. Torqueing them to yield eliminates a majority of the other variables that cause uneven torque load. Once a bolt is torqued into the "flat" part of the stress strain curve it will not apply any more clamp load for any further rotation. If all of the bolts are in the flat part of the curve, then they are all clamping with fairly even load.
If you use an old bolt that is already elongated, it might go past the flat part of the curve and move on up to the ultimate failure point, with uneven clamp load, and a blown head gasket.
Looked this up on Google, as good an explanation for TTY head bolts as any:
http://www.robbos.com.au/myweb/Tech_Bolts.htm
If you do not buy new bolts and blow a head gasket, you will know why.
Good luck,
Mike
The intent of torque to yield bolts is to ensure even and accurate clamping by all of the head bolts. Torqueing them to yield eliminates a majority of the other variables that cause uneven torque load. Once a bolt is torqued into the "flat" part of the stress strain curve it will not apply any more clamp load for any further rotation. If all of the bolts are in the flat part of the curve, then they are all clamping with fairly even load.
If you use an old bolt that is already elongated, it might go past the flat part of the curve and move on up to the ultimate failure point, with uneven clamp load, and a blown head gasket.
Looked this up on Google, as good an explanation for TTY head bolts as any:
http://www.robbos.com.au/myweb/Tech_Bolts.htm
If you do not buy new bolts and blow a head gasket, you will know why.
Good luck,
Mike
03-07-2009, 06:41 AM
#5
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Thanks for your help. I have a Chiltons manual. I just streached the s##% out of two
rod bolts because the main and rod torques were switched. Time to re-torque mains and
head out for two rod bolts and nuts.
Thanks mt goat for the FSM link , now have saved in favorates.
Just a side note - I bought Rock master engine kit with new head bolts.
rod bolts because the main and rod torques were switched. Time to re-torque mains and
head out for two rod bolts and nuts.
Thanks mt goat for the FSM link , now have saved in favorates.
Just a side note - I bought Rock master engine kit with new head bolts.
Last edited by FUSOTECH; 03-07-2009 at 06:44 AM.
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