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MGB Stud coming lose

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Carlbanan56

Carlbanan56

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Today was trying to lose the nuts holding the cylinder head for retorqueing before adjusting the valves. Unfortunately, I might have run into a problem. On some of the studs, the nut didn't come off. Instead, the stud unscrewed from the bottom. This happened on about 3 of all the studs. I have no idea if this is supposed to happen or not. Will this have a big effect when I put them back with my torque wrench? I am inexperienced and young, could I please get some advice?
 

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Use two nuts at the very top of the stud, and tighten them back into the block. then remove nuts and torque them down as normal
 
I'd be interested in hearing how folks retorque the cylinder head nuts/studs. I would think that you would loosen one nut just a bit and then retorque it. If you loosen all the nuts at once, is there a concern that the head gasket might be disturbed? Or do you just retorque the nut, without loosening it first?
mezy said:
Use two nuts at the very top of the stud, and tighten them back into the block. then remove nuts and torque them down as normal
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I'd remove the nut from the stud first, clean the threads with a wire wheel and be sure that the nut spins freely on the stud. When you use the double nuts on the stud, be sure the nuts are high enough so the stud will bottom out before the nuts contact the cylinder head. Leave the washer off for additional clearance. Don't need to torque the stud into the block, just want it snug.
 
Thanks for the replies. How am I supposed to get the nuts off the stud? I have tried to look online but all the information assumes that you can screw on two bolts on the other end. Unfortunately, this is not possible due to the other end having much bigger threads.
 
Carlbanan56 said:
Thanks for the replies. How am I supposed to get the nuts off the stud? I have tried to look online but all the information assumes that you can screw on two bolts on the other end. Unfortunately, this is not possible due to the other end having much bigger threads.
Click to expand...

I'd take the stud with me to a decent hardware store and find a couple of nuts that will properly thread onto the other end. A healthy dose of lubricant at the nut you are trying to remove is always a good thing (I like PB-Blast - have heard really good things about product called Kroil but have never seen it locally). If its REALLY frozen on there a bit of heat might be needed to get its attention but I wouldn't go full medieval on it because you want to be able to reuse this stuff.
 
Removal of the nut that you show, which is jammed on the threads, could be done by clamping the unthreaded body of the stud in a vise and using an impact wrench on the nut. If you don't have an impact you can clamp the stud in a vise, put a box end wrench on the nut, and impact the wrench counterclockwise with a hammer. Or you can put the frozen nut in the vise, put a vise grip so tight you can barely close it on the unthreaded stud CLOSE to the threads and hammer the vise grip counterclockwise. I would not mess with the block end of the stud and, if you do, you may find that the length of the stud, by torsion, absorbs the force you are trying to apply to the stuck nut.
You could also, for about $30.00 at home depot buy the proper tool, called a stud driver (Gear Wrench part #KDT1708), clamp the stuck nut in the vise, and use the driver to turn the stud. As a Florida redneck mechanic, I find this approach reprehensible, but its the right way to do it. If you go with the driver, assure that the hole for the stud exceeds the diameter of the stud you're putting it on.
Double nutting is for tightly installing the stud in the block. The second nut just has to be on by a few threads. However, the stud does not really need to be tightened into the block. If you can get most of the threads at stud bottom into the block threads by hand, you can put the nut on and torque away. The torque spec is only a proxy for stretching the length of the stud enough to get proper hold down on the head gasket and it doesn't matter whether you are turning the top threads, bottom threads, or both.

Bob
 
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And loosen only one nut at a time in the retorque process. More than that increases the risk of head gasket failure. By "loosen", we mean just barely reduce the tightness of the nut.
I should have started my first post with the question "why in (supply own expletive) are you doing this at all?". When I was a BMC line mech, we retorqued at the pre-delivery inspection and at the 1,000 mile service. Never again unless you pull and reinstall the head. There are some shops that never retorque an iron head on an iron block at all, not even at the 1000 mile.
Bob
 
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