Checking head bolt torque

Is there any gain or harm or reason to re-check head bolt torque?
Tractor (Allis Chalmers C) has not been recently worked on.
It does have slight oil weep at the head to block joint.

Probably not but it won't hurt to try
One at a time and in the proper sequence.

just did it on my case 830 had a slight weep of antifreeze under pressure, fixed. loosen the bolt and then apply torque in proper sequence.

Let me just emphasize what ackson65 said. You want to break them loose counterclockwise before checking torque.

Agree with the loosening first, but don't really loosen it, just enough to feel it move, then go back to the listed torque.

I'd drain the coolant first, to at least below the head gasket.

Hello bcny,

I would just use the proper sequence and torque them down to the final torque. Unless directed by the head gasket instructions to loosen them first!

Guido.

(quoted from post at 16:19:29 06/03/18) Hello bcny,

I would just use the proper sequence and torque them down to the final torque. Unless directed by the head gasket instructions to loosen them first!

Guido.

Click to expand...

Guido you may want to look at the OP again. This motor has not been recently worked on but has a slight oil leak which he wants to try to eliminate by torquing the head bolts. Though it is not likely to work, I believe that he has very little to loose so why not? I think that most of us here agree that after a few years of working and heat and cool cycles that nuts and bolts in use pretty much anywhere on pretty much any machine that heats up with use will tend to get a little stuck or, if you will, held by more than just the normal stretch of the bolt. So when you combine the friction added to the stretch, it is highly unlikely that any bolt will break loose and move one degree of clockwise rotation. Whereas if bony first eliminates the added friction with just a 3-4 degreee counterclockwise movement, and then goes to torque spec. clockwise, he will probably gain a little here and there and possibly even stop the leak.

(quoted from post at 16:19:29 06/03/18) Hello bcny,

I would just use the proper sequence and torque them down to the final torque. Unless directed by the head gasket instructions to loosen them first!

Guido.

Click to expand...

Guido you may want to look at the OP again. This motor has not been recently worked on but has a slight oil leak which he wants to try to eliminate by torquing the head bolts. Though it is not likely to work, I believe that he has very little to loose so why not? I think that most of us here agree that after a few years of working and heat and cool cycles that nuts and bolts in use pretty much anywhere on pretty much any machine that heats up with use will tend to get a little stuck or, if you will, held by more than just the normal stretch of the bolt. So when you combine the friction added to the stretch, it is highly unlikely that any bolt will break loose and move one degree of clockwise rotation. Whereas if bcny first eliminates the added friction with just a 3-4 degreee counterclockwise movement, and then goes to torque spec. clockwise, he will probably gain a little here and there and possibly even stop the leak.

I have never tried what you propose but I would mark each bolt.
Remove one bolt in tightening sequence, clean threads, install to same as it was as for mark,
Repeat till all bolts have been done, then tighten to specifications in a couple of passes.
Let us know how it turns out. As I understand it head gaskets can relax a bit after time and re torquing might help.

(quoted from post at 08:27:02 06/04/18) I have never tried what you propose but I would mark each bolt.
Remove one bolt in tightening sequence, clean threads, install to same as it was as for mark,
Repeat till all bolts have been done, then tighten to specifications in a couple of passes.
Let us know how it turns out. As I understand it head gaskets can relax a bit after time and re torquing might help.

Click to expand...

What is the danger of a bolt breaking? If that happened, of course the problem would go from bad to worse.
Stan

(quoted from post at 06:30:48 06/04/18)

(quoted from post at 08:27:02 06/04/18) I have never tried what you propose but I would mark each bolt.
Remove one bolt in tightening sequence, clean threads, install to same as it was as for mark,
Repeat till all bolts have been done, then tighten to specifications in a couple of passes.
Let us know how it turns out. As I understand it head gaskets can relax a bit after time and re torquing might help.

Click to expand...

What is the danger of a bolt breaking? If that happened, of course the problem would go from bad to worse.
Stan

Click to expand...

The danger of breaking a bolt is extremely low unless the torque value that you use is way off.

Years ago bought a JD 45 combine supposedly just overhauled. It had that oil leak. In trying to get things checked told to check the bolt torque, supposed to be something like 145#, had to buy the wrench and checked and it was only tightened to about 80#. Did not try to back off any, just tightened to recemonded and leak stoped and ran it for years afterward with no problem there.

(quoted from post at 07:42:41 06/04/18) Years ago bought a JD 45 combine supposedly just overhauled. It had that oil leak. In trying to get things checked told to check the bolt torque, supposed to be something like 145#, had to buy the wrench and checked and it was only tightened to about 80#. Did not try to back off any, just tightened to recemonded and leak stoped and ran it for years afterward with no problem there.

Click to expand...

Yes Leroy, when it was so loose compared to where it was supposed to be there would be no need to break it loose first.