leave them if they're reasonably decent, so we don't have to say we told you so. not that you can't do it, but generally, regardless of the procedure, most don't want to come out and they break. then you're on to the next adventure with them.

Sounds good guys....as much as I like shiny and new fasteners..I will err on the side of caution, and just let them be and goop them up with Anti Seize.
Thanks for all your input.
Yasin

Copper grease with copper nuts is a great way to be able to get it all apart again some day.

As some people here could vouched for my adventure for putting the SSI's in, I did end up doing one Time-Sert. But with the help of this board, it was easy.

Of the 12 studs, the first 2 nuts ca me out with the stud still with them, the next 2 broke at the barrel nuts, so that is when I decided to cut the nuts of the remaining 8 nuts.

I use a straight stud puller with an air gun starting low and slowly increasing the pressure. Except for the one that broke twice (last time flush) they all came out rather easely.

I would definitely do it again. Drilling and Time-Serting is not a big thing. This was my first tap ever :D

http://forums.pelicanparts.com/porsche-911-technical-forum/592476-help-exaust-stud-drilling.html

http://forums.pelicanparts.com/uploa...1341882856.jpg

a couple broke on my SSI install. I ground flush the stud and drilled a small hole dead center. then increased the drill size until close to the edge and grabbed the threads with pliers and removed it, cleaned the hole out with a tap,

http://forums.pelicanparts.com/uploa...1341892664.jpg
http://forums.pelicanparts.com/uploa...1341892689.jpg
http://forums.pelicanparts.com/uploa...1341892711.jpg
http://forums.pelicanparts.com/uploa...1341892729.jpg

it can be done, just be careful!

Exact Drill bit sizes for drilling out exhaust studs?
 

Had to bump this thread and ask couple questions...
I'm in the middle of a refresh on my SC 3.0, the HE are/were totally shot, so off they came! 2 studs came out with the nuts and I had one snap off mid stud and now have to go the rest of the way. Some of the studs are totally bent and threads rusted down to nil.

So my questions to JB are:
What size drill bits did you use for pilot hole and final drill of the threads?
I saw 3/16 for pilot and 17/64 on another thread, correct?

Here is the victim on the OR table.
http://forums.pelicanparts.com/uploa...1357333630.jpg

Each bank waiting their turn
http://forums.pelicanparts.com/uploa...1357333699.jpg


http://forums.pelicanparts.com/uploa...1357333727.jpg

I am making a jig with 1/4" x 2" flat stock

Using HSS gold drill bits along with titanium bits and MAPP gas... I tried SlowandRusty's method of Irwin tool's bolt extractor with impact gun...even with heat it snapped a bolt clean :mad: so I want to take a step back and start over with a more traditional plan, then once my "drill out the snapped bolt" process is proven, go back to the impact gun method with MAPP and see what happens :eek:

TIA
Jason

Check these out (drill guide bushings).

items in WOLF TOOLING AND MACHINERY store on eBay!

They come as a set. You slide one over the stud (cut down to the correct length), then slide smaller ones inside the first one.

Then you drill with a small drill and it will be dead center.

remove the guide bushings (one at a time) and go to larger bits until you have most of the stud out, then remove with pliers and/or clean with tap.

maybe 20 minutes each stud, no possibility of bunging the threads.

Genious! My friend the airframe mechanic had a set. I was too stoopid and had already broken a couple off flush with the head but we still used them with some success.

FWIW I think if you drill out to 1/4" you can get the rest of the stud out pretty easily.

Note - DO not use the spiral cone easy outs - they push the stud walls out into the aluminum and will not work. There is another type of easy out that you hammer in that MIGHT work (they are square). Hopefully you wont have to mess with them.

This was posted a while ago on this site:

"The April/May 2007 edition of Machinist's Workshop did a test of penetrating oils where they measured the force required to loosen rusty test devices. Buy the issue if you want to see how they did the test. The results reported were interesting. The lower the number of pounds the better. Mighty interesting results for simple acetone and transmission fluid!

Penetrating oil . Average load .. Price per fluid ounce
None ................. 516 pounds .
WD-40 .............. 238 pounds .. $0.25
PB Blaster ......... 214 pounds .. $0.35
Liquid Wrench ... 127 pounds .. $0.21
Kano Kroil ........ 106 pounds .. $0.75
ATF-Acetone mix.. 53 pounds .. $0.10

The ATF-Acetone mix was a 50/50 mix (1 to 1 ratio)."

I would go for the ATF-Acetone mix for these exhaust studs, then use heat. Why not go 100% on getting these things loose? Never tried that mix, though, although the liquid wrench does seem to work pretty well on other things.

FWIW I was not able to get the heads hot enough with MAP gas. If you cant weld a stud on and use an air impact that you can throttle way down to low torque you run the risk of breaking them off flush.

I used a stud removal tool (shown above) that looked like a drill chuck and an electric impact that was not adjustable for torque, I heated the heads for 10 mins around the stud and SNAP they broke right off flush with the head when I hit them with the electric impact.

I might try this method again with an adjustable impact gun but I decided to cut my losses and re-use the rest of the studs on this go around.

My motor is still in the car - the PB Blaster repeated soakings did not touch the stud to head corrosion. YMMV

Same experience here.... MAPP and numerous sessions soaking in PB blaster didn't help at all...

I wouldn't even bother but the studs are all beat up, bent, missing threads etc. so I HAVE to do this. Plus the engine is on the stand and I might as well see this through so I don't end up on my back under the car one day down the road!

Thanks guys for the tips and comments. Moral support alone is critical at this point!

So, I made my own drilling jig and started in again on the first snapped stud. This one was flush with the head.
Take a look at the pic. Not sure where to go from here. The drilled hole that goes all the way down through the old stud is a 1/4" my plan is to follow it with the 17/64" bit then run a thread cutter tool down and see what I have left. I tried the "pick the threads out" and quit after 30 min. No way seized threads are coming away fem that aluminum with this approach!

Here's where I'm at with that first pass and just dipping the tip in with a 17/64 but got nervous I was off center!
http://forums.pelicanparts.com/uploa...1357364442.jpg

Can I just run the 17/64 down in there and follow with a #8 1.25 thread cutter?

I've got all the tools but a welder.

http://forums.pelicanparts.com/uploa...1357364865.jpg

The air impact with bolt extractor didn't work, I put a guage regulator on it and at light setting it either wouldn't hammer or just bit in and stopped, when I bumped the air pressure up it hammered and then snapped the bolt off flush! I'm pretty apprehensive about doing that again... Used lots of heat too.


http://forums.pelicanparts.com/uploa...1357364744.jpg


What do you guys think?
A) Run a bit down and make a smooth hole and cut new threads
B) try to salvage the current threaded hole (some how)
C) Drill for a time cert?

I've got at least 10 more studs to do :eek::eek::eek:, so if its easier to just drill them out and time cert them I have no problem doing that! This pace without results is ridiculous...


TIA
Jason

Aluminum and stainless steel is a great combo if you want to destroy the aluminum.
Look up dissimilar corrosion.

time for some time-serts

++ TIME-SERT Metric Kits ++ thread repair kits and inserts repair stripped threads damaged threads repaired threads threaded inserts for metal thread inserts for metal aluminum inserts threaded inserts for aluminum

watch some of the installation videos

Thanks JB will do!

Check post 1 of http://forums.pelicanparts.com/porsche-911-technical-forum/597019-time-serts-rescue.html

Got my kit from Amazon for about 75 delivered. While at it order different size to make a full kit.

I had a hole or two like that.

I used a dremel with a bit that had "teeth" on the side, kinda like a drill bit? not sure what y ou call them. And carefully removed more of the stud on the meaty side (since you are off center). Kept enlarging the hole with the dremel until I could get the tap started.

The Tap really eats up the stud and you have to remove and clean it almost every half turn. I dont have mine together all the way yet but the new studs go in and tight. If they have problems later I will Time Sert but I dont think it will be a problem, there are lots of threads up in there. The first couple threads are not 'factory' for sure but I am fairly confident.

I had to do this for 10 of the 12 studs... got the tool from Christian (forum member here in Pelican).

http://i151.photobucket.com/albums/s...BA7056B899.jpg

http://i151.photobucket.com/albums/s...ps1b85c7e0.jpg

http://i151.photobucket.com/albums/s...psa4a96e26.jpg

http://i151.photobucket.com/albums/s...ps33b29ceb.jpg

Years ago I broke off two of mine, despite lots of care not to.

I had a machine shop make me a similar drilling jig that allowed me to drill them out on the car. It worked pretty well but needed better rotational stability. I think Christian's tool is better. Both tools have the same problem though....if you break two off on the same exhaust port it's pretty tough to deal with.

http://forums.pelicanparts.com/uploa...1357401845.jpg

Does anybody have the center to center dimension of the exhaust studs (3.2L), need to replace studs as well, tool looks fairly straightforward to make. Want to be as accurate as possible, looks like if not dead nuts centered can open up another can of worms. Thanks.

66.25mm would get you real close.

I used Timeserts as well as two of my studs snapped.