I'm a stud, Repair guy, hopefully Options

[Porschef]

Well, it seems that the constant reoccurrence of an exhaust leak stemmed from a pulling exhaust stud. I'd tighten it, the noise would go away, come back, rinse, repeat.

A couple of weeks ago I took her out for a spin, heard that sound, and got under after cooling to see what the deal was.

A quarter turn later, the stud dropped right out.

So I'm gonna do an EZLOK insert, and pray.

Pics to follow, along with any tips, snags, or bonifide cuss sessions.

The fun never ends

Right Joe? (IMG:style_emoticons/default/hissyfit.gif)

[ThePaintedMan]

Don't let anyone fool you, it's not that hard. I did three at once. Mark the bit depth, and drill at the exact same angle the original stud was at. If you can, use some kind of drilling lubricant - Harbor Freight sells a good foaming kind that won't drip out.

I know that others here have far more experience than I do, but personally, I wouldn't worry about the step stud. If THAT one pulls out, you won't have enough aluminum left to tap the hole for a Time-Sert/EZ Lok. If you install a Time-Sert (which I would recommend) the first time correctly, with red Locktite, you won't have to do this job again later.

Sounds intuitive, but some may not know this - you must remove the heat exchanger first so you can see what you're doing.

[Rand]

Don't let anyone fool you, it's not that hard. I did three at once. Mark the bit depth, and drill at the exact same angle the original stud was at. If you can, use some kind of drilling lubricant - Harbor Freight sells a good foaming kind that won't drip out.

I know that others here have far more experience than I do, but personally, I wouldn't worry about the step stud. If THAT one pulls out, you won't have enough aluminum left to tap the hole for a Time-Sert/EZ Lok. If you install a Time-Sert (which I would recommend) the first time correctly, with red Locktite, you won't have to do this job again later.

Sounds intuitive, but some may not know this - you must remove the heat exchanger first so you can see what you're doing.

Wait, what? About the step stud? You prefer an insert? With Loctite? Did I hear that right? Oof. Really? That's why I'm not painted.

[ThePaintedMan]

Wait, what? About the step stud? You prefer an insert? With Loctite? Did I hear that right? Oof. Really? That's why I'm not painted.

Sarcasm aside (and I did say that you guys know more than I do (IMG:style_emoticons/default/pray.gif) ), a Time Insert is a stronger and more reliable option. If I remember correctly, several engine builders here have recommended that when heads are rebuilt that Time Serts be installed to avoid future headaches. They are along the same lines as "case savers" for Type 1s, which are installed to prevent case studs from pulling in high HP applications.

Aluminum gets brittle as it is heat cycled over and over. If you drill out a stud, re-tap the aluminum and install a step stud, is it not just a matter of time before the step stud pulls out from the same forces that pulled out the initial stud?

Finally, if a Time Sert pulls out (which I have not heard of), another can be reinstalled. If a step stud pulls out, the hole will then be large enough that it is doubtful you'll find another step stud large enough at the base, but still small enough at the stem to fit our heat exchangers.

Anyway, the point of my original post was to reassure Porschef that if he goes slow and takes the right precautions, it's not as risky as one might think. Drill straight and do NOT drill too deep. You'll be fine.

[worn]

Finally, if a Time Sert pulls out (which I have not heard of), another can be reinstalled. If a step stud pulls out, the hole will then be large enough that it is doubtful you'll find another step stud large enough at the base, but still small enough at the stem to fit our heat exchangers.

I am afraid that Time Certs aren't magic and can pull out. At least that is what I read in the 911 books. Also, if a time cert actually pulls out, that leaves a pretty big hole. I don't think you are going to get it back in. With that said, I like time certs. They move the stud interface from steel to aluminum to steel-steel. Then when the electrolysis corrosion fairy comes calling, it will lock the time cert in place, not the stud. And hopefully the loctite will even prevent that.

[ThePaintedMan]

I am afraid that Time Certs aren't magic and can pull out. At least that is what I read in the 911 books. Also, if a time cert actually pulls out, that leaves a pretty big hole. I don't think you are going to get it back in. With that said, I like time certs. They move the stud interface from steel to aluminum to steel-steel. Then when the electrolysis corrosion fairy comes calling, it will lock the time cert in place, not the stud. And hopefully the loctite will even prevent that.

Sorry, I guess I meant loosen, as in the Time Sert unscrews with the stud. I imagine it is possible for the Sert to pull out of the aluminum, but I personally have not witnessed it.

Your point about the steel-steel interface is a good one, and exactly what the designers had in mind, from what I understand. If I ever rebuild a set of heads, I am strongly considering installing Serts in each exhaust stud hole from the get-go; I trust them that much.