Question on possible overtorque on head bolt

[98Redbird]

Just a quick question on a clearwater head install that I did on my 2001 XJ last night. Went through the proper torque procedure, 22, 45 (x2), then 110 on all bolts except 11 (drivers side front), which was 100 with thread sealant.

I went through and checked them all again at 110, but on the front passengers side (#12 I guess it would be) the wrench didn't click. I think it got hung up internally, and then popped free. The bolt turned probably another 10-15 degrees or so before this happened.

So I guess my worry is overtorque now. Should I pull that bolt and install a new one? Or leave it? Will that likely cause any issues down the line?

If it needs to be replaced, can I purchase just one bolt? Or will I need the set?

**Also, on the rear drivers side bolt (the one that needs to be installed when the head goes in), I could not fit the deep well socket, and the torque wrench in there. It was too tall to clear, so I used a 3/8 ratchet wrench and 1/2 socket and just did it "by feel" using how tight the torqued bolts "felt" as my gauge. I think it is pretty close. How did you guys do this?**

Thanks

 

[old_man]

Just leave it. I would be really surprised if you have a problem.

 

[RedHeep]

Unless you're using a cal lab for your torque wrench, the variances on the head bolts are probably all within the same range that you've got on that one bolt. There are a lot of bolts on a 4.0 head.

 

[md21722]

I use a 3/8" deep socket and 3/8" torque wrench on the rear bolt. Others have said a 12 pt 13mm will get it done but it ain't pretty. I haven't had any problems with head bolts like you've described. I do normally clean out the threads really well.

 

[trippled]

Head bolts are designed to stretch to equalize clamp force with variances in torque. Id run it.

 

[RedHeep]

Head bolts are designed to stretch to equalize clamp force with variances in torque. Id run it.

Clamping force is related to a lot of variables, but is most affected by dry or wet installation with a given torque. I don't think you said what you meant, but it's important to make sure that people don't think that head bolts are smart and can cover up your mistakes.

They don't "stretch" to make it all better. Now a wet installation will lubricate the threads and also provide a certain amount of resistance if the threads are cut tight or loose and provide an equal amount of clamping force given using the same tool set to the same torque. The equalization of torque on a multiple fastener installation is often more important than hitting a certain torque rather than a torque range. But head bolts are too far apart to be concerned about that.

An example of the direct relationship between torque and clamping force can be seen here:

http://www.spaenaur.com/pdf/sectionD/D48.pdf

But that's an over-simplification of a lot of other things involved in fastener installation, including the material of the fastener and the material of the component or fastener it's being threaded into.

Long story short, you can probably do a number on a 4.0 cylinder head and it will still run. Get it close and it will last a long time.

 

[trippled]

Clamping force is related to a lot of variables, but is most affected by dry or wet installation with a given torque. I don't think you said what you meant, but it's important to make sure that people don't think that head bolts are smart and can cover up your mistakes.

They don't "stretch" to make it all better. Now a wet installation will lubricate the threads and also provide a certain amount of resistance if the threads are cut tight or loose and provide an equal amount of clamping force given using the same tool set to the same torque. The equalization of torque on a multiple fastener installation is often more important than hitting a certain torque rather than a torque range. But head bolts are too far apart to be concerned about that.

An example of the direct relationship between torque and clamping force can be seen here:

http://www.spaenaur.com/pdf/sectionD/D48.pdf

But that's an over-simplification of a lot of other things involved in fastener installation, including the material of the fastener and the material of the component or fastener it's being threaded into.

Long story short, you can probably do a number on a 4.0 cylinder head and it will still run. Get it close and it will last a long time.

I agree. I should have said yield, since thats what torque to yield head bolts do, and only meant it as a generalization.