Legoland951

Uh, why did you tighten them in groups of 3? I tighten every one of them in an X pattern from center out starting from 30, 60, then wait 30 min before 85 or 90. I think the angle method is silly and I would bet the difference in friction from stud to stud is negligible when the threads are clean and lubricated as every stud would have very similar friction, thus consistent clamping force. In fact, the angle method doesn't take in account stretch. Analyzing forces from torsional to vertical along the axis of the stud you can actually calculate the amount of clamping force given the angle of the threads regardless of stretch so I can't imagine why the angle method would work better. No high end aftermarket stud/rod manufacturer that I know uses the angle method for rods, studs, etc.

Sigh, the terms Young's modulus, ultimate strength, elasticity, and visions of time spent in lab testing material hardness 20 years ago flashes in my mind...

FRporscheman

Lego, the group of 3 referred to the 3 weakly torqued nuts that were left after I tried loosening/retorquing one (of four). The last 3 were the leftmost of the 10, and in normal torquing sequence X pattern I would do the mid-left top, far-left bottom, far-left top, so I just did it like that without loosening the other nuts which were torqued well. I saw no point in doing them all over.

You have more experience in the field of stress analysis than I; I've only taken a couple classes, but I would also think that a torque value would be proportional to stud stretch if we can manage to control friction, and a turn-angle value relies on all 10 studs having the same consistency and characteristics so they hopefully/theoretically stretch and clamp by the same amount. Well in my case they definitely did not yield consistent torque values.

Do you think 70ftlbs is enough torque for a 16v head (longer studs)? Right now all the formerly problematic ones are at 70, and the other ones were checked to be around 70 with the beam style and the clicker. If the 15ftlbs-60*-90* yielded about 70ftlbs final torque on the 6 nuts that "behaved" then my intuition tells me 70 is a good number...

Legoland951

Sorry but I don't play with 16v cars much though I torque my 8v heads to 85 ftlb. I spent some time 20 years AGO but definitely did not spend that much time in the lab as much as calculating lattice and dislocation energies. Its amazing how much one forgets in 20 years though.