So what if the HEAD BOLTS don't torque --HELP

Bear80

 
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Okay, so I just pulled myself off the floor with the realization that I have to pull the head back off to put on another gasket with new *explicit deleted* bolts.

Last wednesday I got the head bolts torqued and turned 90* twice as stated in the FSM. Tonight I went out just to check the final torque as a few members recommened and it appears there are two bad bolts. The number 3 and 6 bolt in the torque sequence would not torque like all the others.

I had a hard click at 96 lb/ft across the pattern, with a few that seemed to tighten. Since a few seemed tighter than 96 I went to try 98 and that seemed the proper value for those. I then went back to set all of them at 98 but the third and sixth bolt kept turning. I've now turned them almost 90* more. They feel like either the bolt is about to break or the threads are about to strip. All the other bolts click hard and right away at 98 lb/ft.

What is the deal with these two bolts?? Just my luck or what? :bang:
 
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-Spike-

 
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If you've damaged the threads in the block, stopping now probably won't help. If it were mine I'd probably torque them until I was sure they were trashed, or they stopped turning. Hopefully someone else will have some advice that is actually helpful. :D

-Spike
 

Bear80

 
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I have the suspicion that the bolts are about to snap. Either way I'm mentally prepared for a new gasket and bolts.
 

IdahoDoug

 
 
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One strong possibility is that there was oil in the bottom of the bolt holes and the bolts hydrolocked on incompressible oil. With no way to know if this happened, I'd simply loosen all the bolts in proper sequence and pull those two bolts all the way out and have a look at them. If you're experienced with a caliper/micrometer then measure their thickness as the FSM indicates to see if they're useable and that should uncover any problems with the bolt. If they're in spec, then it was oil hydrolock - I simply cannot imagine the block threads are messed up. In fact, no way. It's gonna be too much oil or an oddly defective pair of bolts (unlikely). At this point, you should pull and measure, or have them all measured at a machine shop. I had a pro measure mine at a shop. You've gotta eliminate the bolts as the issue. If you have oil down there, take a shop vac and stick a straw in the crevice tool and duct tape it, then slurp out the holes and slap things back together.

Unless I'm missing something (anyone chime in) you don't need a new gasket if you don't pull the head back off - just retorque.

Look at it this way. You did EXACTLY the right thing double checking them and it PAID OFF big time for you. Yeah, it's a pisser and you're not where you wanted to be tonight, but boy did you dodge a bullet. If you were paying someone to do this, I'd say 90% chance they would have completely missed it by not taking the time you did. Congratulations on that.

DougM
 

Bear80

 
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Thanks for the upbeat attitude Doug. ;) I have a better appreciation now of what you went through in your previous experiences. I hear where you're comming from but I did blow out the holes with compressed air and chase the threads. My plan is to pull all the bolts out and inspect them. As for my piece of mind, I'm probably still going to replace the set and gasket. I've been to meticulous with this job (nearly 3 months) not to get it 110%.
 
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^^^^^Pull the head.^^^^^

get it out of the way and do a proper inspection of the threads in the block, use a bottoming tap to chase the threads and make sure they are sound and there is nothing impeding the bolt, measure the length of all the bolts to see if the two in question have been overtorqued and hit their yield-point. If in doubt replace ALL of the bolts with new.

Again I'll qualify my comments by saying I'm not the most Toyota savy person but this is sound practice for any piece of equipment that is torque critical.
 

landtank

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I would pull only those two bolts and leave the rest in place. Then inspect the threads and if they looked fine I would attach a small piece of rubber tubing on a shop vac with some duct tape and slide it down into the holes and vacuum out them real good. IMO removing just those two and leaving the rest will have no effect on anything.

I have a set of used bolts from a truck that I converted over to studs if you need a couple.
 

60wag

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Are the bolts "torque to yield" bolts? I thought a spec that said "torque to xx ftlbs, then 90 degrees" meant the bolts were stressed into the yield range upon installation. These type of bolts should NEVER be reused - just not sure if this applies to a 1FZ. If so, new bolts should solve the problem.
 

landtank

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they are torque to yield but there is factory specs concerning the ability of reusing them. I'm not aware of anyone having to replace them all.

I'm thinking there is some oil or debris in those holes and it just needs to be cleared out.
 
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Are the bolts "torque to yield" bolts? I thought a spec that said "torque to xx ftlbs, then 90 degrees" meant the bolts were stressed into the yield range upon installation. These type of bolts should NEVER be reused - just not sure if this applies to a 1FZ. If so, new bolts should solve the problem.
They can be reused if they haven't been heat cycled or stretched beyond their yield range. Easy to ck, measure a pulled one and compare to new. But the threads will be damaged if hydrolocked. I'm with Doug on this, sounds like hydrolock (oil or AF), could be from stuff in the head that migrated before you got the gasket tight. I too would not bother with a new head gasket.

I have seen batches of head bolts that a couple will not stretch to yield properly, and need replacement. I'd clean the holes, get two new bolts and try again.

HTH and my .02

Scott J
94 FZJ80 Supercharged
 
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If the block is steal then the bolts are bad. If it aluminum the holes are striped.

I would just keep turning them the bolts will click when they are tight enough. LOL
 
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