Stripped a cylinder head nut

I was torquing down my cylinder head when I felt one of the nuts strip. It was the inside pedestal stud in the #2 position in the torquing sequence. This isn’t one of the nine main studs that hold the head to the block but one of the four smaller studs that holds the rocker assembly to the head. The moment I felt it loosen I backed off and left it be. I then continued to tighten the others to the prescribed 42 ft. lbs. without incident.

As I see it, I have three options:
Leave it be. There’s plenty holding that rocker assembly down; it isn’t going anywhere.
Remove the stud and replace it with a new stud, washer, and nut. Sure, it won’t be tightened in sequence with all the others, but it is not one of the head bolts so it should be okay.
Start all over. Removed the head, replace all the bolts, washers, and nuts, and replace the head gasket.

To me option #3 seems like overkill. I’m not restoring the thing to a pristine level of high performance; I just want it running. I figure option #1 would be fine--for a while, but eventually it may give way and then I’d be sorry. So, that leaves option #2. Easy and quick, and it solves my problem.

What do you all think?

Lon
’65 MG Midget MkII

I'd go for #2 then in 500 miles retorque all in sequence

I think 42 ft-lbs on those rocker pedestal nuts is a bit much. Check your manual again. And yes, replace that stud/nut.

Rocker pedestal nut torque should be 25 ft-lbs, head studs should be 50 ft-lbs for 1275 and 40 (some publications say 45) for 1098/948. Manifolds should be 15 ft-lbs.

Yep, rocker pedestal studs get only 25 lb-ft. That's even on the high side for a 5/16" fastener. If you have the rocker grub screw locking tab on the #2 pedestal, you may be able to double nut the offending stud and remove. Then replace with a good one, new nut and lock washer. Not a big deal at all. Do this at your head gasket retorque time and all will be well.

1275 head studs will have a drill point in, or a #22 stamped into the top.

HTH,
Mike Miller

Thanks everyone for your help! Replaced the bolts and nuts today, torqued it down (at the correct poundage this time), and it's good to go!

Lon

Lon_S said:

(at the correct poundage this time),

Click to expand...

Poundage?????

Like this: :hammer:

No no no, use a wrench, it works much better. :thumbsup:

No wonder it was stripped.

LOL