How to check for broken head studs while the valvecovers are off?

[vash]

this is a great thread.
a stud or a bolt, whatever, and the components being held together by the fasteners, in reality, could care less what the torque is. tension is the key. somebody way back when, took the various fasteners and put them into a skidmore (measures tension), to find out what torque ( perfectly lubed units) would get the required tension needed (then spec'ed out the torque values we use as weekend mechs). when i had my valve covers off, i took a careful look for loose hardware bouncing around, and that was pretty much it. i didnt want to add any torsion into the mix, by cranking on anything.
one time at work, we had a bunch of bolts, we had to confirm with a skidmore. we measure rolling torque (bolt spins) and read the corresponding tension on the skidmore. just to see if bolts meet spec. for kicks, we decided to crank a bolt until failure. this was a 4.5" long 7/8 bolt, we use for seismic retrofitting of bridges. with big wrench we actually generated that stress strain curve you see in all textbooks on the matter. i think smart guys design a certian amount of tension into the fastener, so it will act like a spring during the elastic portion of the curve, torquing it extra after the fact would introduce a bunch of unknowns that could take it to the upper parts of the curve near failure.

[ChrisBennet]

I know enough to know when I don't know enough - and I don't know enough on this matter. That said, my fear is that an old rusty stud might still be strong enough to clamp the head down but not strong enough to take the twisting force (of a retorque) now that it is covered with rust induced stress risers. Can any of you guys shed more light on this?

The Raceware studs are a different animal so I don't know if comparison with them makes sense. The Raceware studs are covered with some sort of solid lubricant and they are not Loctited into the case.
-Chris

[1980 911 sc]

ok I am about ready to cry....I am going to be checking my head studs for the first time since I owned the 80 euro SC this weekend.....I hear noise when I accelerate hard and it really seems like a dog below 3000 rpms. I have been chasing my tail about it. I have sent several emails and posts asking about detonation, timing chains, and every thing else I could think of.....intentionally avoiding the head studs (out of fear).

I tend to obsess about things, so tommarow I will be facing the music and checking them...and I am a nervous wreck =P

I do have one question that is sorta off topic.....lets say I have a few head studs bad.....is this an intellegent time to say buy some 10.3:1 or so pistons, S cams, and a megasqurit fuel control kit? I am thinking this could yield like 240+.

I think my car is supposed to wiegh in at 188HP. I am wondering if the complete lack of low power is because of head stud failure, or if I am just greedy?

One last thing? why are cylinders so damned exspensive and pistons are less than $1K? Is it stupid to just change the pistons?

[vash]

dont cry, if you start crying, i'll start crying...

[Randy Webb]

All Porsche owners are obsessive.... Don't worry too much...

W/out more real info, I think I would torque at least the MG cases (2.7L). If I had a Al 3L ... I'd prob. do it but sounds like others would not (based on Wayne's post).

next time I see the race engine builder I frequent, I'll ask him. Need to see him anyway after I run my Al cased hotrod 3.2L for a while (but I need to put it in first....)

Also, maybe Steve Wiener will see this -- he is usually on Rennlist, so someone could copy the salient posts from here to ther and ask him to look at it.

Also, the next person to take Jeryy W's engine class could ask him and/or BA. They are glad to answer questions during the class.

[aigel]

Originally posted by 1980 911 sc

I think my car is supposed to wiegh in at 188HP. I am wondering if the complete lack of low power is because of head stud failure, or if I am just greedy?

One last thing? why are cylinders so damned exspensive and pistons are less than $1K? \

Have you driven any other SC? They really do not have much under 3000 rpm. These engines like to be between 3500 and redline! You may be greedy, who knows.

A valve adjustment and checking the studs is never a bad idea. Don't sweat it until you actually get to check the studs. I doubt those noises and the lack of power you describe are good indicators that anything is wrong with your head studs.

Why are cylinders more than pistons? That must be in the production process. I think the shape of a piston is easier to achieve.

I would keep what you have and not give up until you have been through the entire setup. The grass is always greener on the other side of the fence...

Cheers, George