need help on broken stud

[don gilbert]

spent an hour on the search function, too time consuming. while fixing a head gasket leak on my 82 3.0 motor, i decided to upgrade a few things, one was replacing the lower studs with steel ones. None were broken, or even rusted, just thought it would be a good thing to do. all came out easy but two. applied heat, double nutted, finally a pipe wrench twisted them about 360 degrees before they snapped. ground one down, went to homo depot for bits, (good ones i thought, carbide) got a nice center punch made but the bits wont cut. is there a special bit i need to find, what other options before tearing down for machine shop? thanks, don

[snbush67]

I used titanium tips when drilling my exhaust studs use lots of cutting fluid, Slow and steady with a lot of pressure use your shoulder. Someone recommended using leverage. I also used a jig but if you can keep it going straight you will be allright.

[James Brown]

Don are you talking about the head studs or the exhaust studs?

[sailchef]

Originally Posted by don gilbert

None were broken, or even rusted,

finally a pipe wrench twisted them about 360 degrees before they snapped

Man I feel your pain.

[JohnJL]

Aircooled 911s dont have head gaskets, are you refering to intake, exhaust or cylinders?

[David]

Drilling Dilavar head studs with a hand drill is a major PITA. I found a drill with concave section opposite the drill chuck so I could use a cheater bar to apply more pressue. I still went through several drill bits. Did they snap off right at the case?

[don gilbert]

john, the 3.0 sc engine does indeed have a head gasket. both head studs snappen a few inchs above the case, but i have cut one down even so i could start drilling. I guess i need to find the best bit to buy, but which ones? any advice from anyone? this is getting to be a real pain. wish i would have left them alone now. thanks, don

[Gunter]

Don,

This very tricky and potentially costly; procede very carefully.
It is virtually impossible to drill straight with a hand-held motor into the broken head studs without the danger of wandering off into the softer Alu material of the case.
Carbide tip drills are for concrete, etc. but don't have the right cutting angle for metal.
You'll need very high quality bits, cutting oil, a precise, deep center mark in the stump and 2 people:
One to hold the drill motor straight and control power and the other one to apply some pressure with a rigged 2x4. Rope-sling on one end, motor in the middle and the 2nd person pushes/pulls down on the 2x4 gently but firmly.
Issues to consider: Keep the motor straight, don't let the drill bit wander off, easy pressure from the 2nd person.

Done it many times on machinery in the field but with Millwrights or Machinist who know how.
Grinding the right angle on the drill bit is important.
Can you find someone with Machinist background to help you?
Do you have an angle-drill?
Or just a regular 3/8" drill motor?

[mca]

Originally Posted by JohnJL

Aircooled 911s dont have head gaskets, are you refering to intake, exhaust or cylinders?

John,

I believe that he is talking about the ring that sits in the groove on top of the cylinder.

There is a copper gasket between the cylinder and the case too - maybe you are thinking of that.

Don,

Best luck man! Hope it works out. Curse that Dilivar.

[BLEW911]

Solid carbide drill bits are available in any size at all machine shop tool suppliers. They are also sold by McMASTER-CARR on line. You can buy various lengths and drill point angles. All the info you need is there on their web site.
A drill press or even better, a mill, is the best way to keep that drill going straight.

Don

[JerryL]

Solid carbide is too brittle to use in a hand drill, you need a real machining center to take advantage of that.

See if you can find a TI coated 135 degree split point drill in a screw machine length (shorter much less flex)
Since you are buying stuff any way get or borrow a solid lathe type center drill much easier to get the hole started (also very short) in the right place then switch drills.

You may try the above split point in a lefthanded twist (not hard to find) as you drill and generate heat vibration and pressure sometimes it will break loose and screw out. I keep a few sizes in the tool box just for jobs like this, even if it does not start to un screw you are no worse off, it may break loose after drilling a bit of depth and allowing the "shell" of the screw to relax.

Try msc.com for drills if you dont have a real machinist type supply store around.

The 135 deg point is wider and helps center also the point is thinned to a very narrow tip web to aid starting and self centering when drilling, lots of oil, low drill rpm and HIGH PRESSURE

Good luck, take your time and do this properly or the slippery slope will catch up FAST

Regards

[David]

I built a jig for drilling these, let me know if you want to use it:

[don gilbert]

here is where im at right now. my brother jeff ( a machinist in the navy) rigged up a drill press bolted sqaure to the block, trying a cobalt bit, its cutting but very slowly, will need about 10 bits im sure. will let you know how it works out. wish me luck and pray for me tonight, thanks , don

[JerryL]

Looks like the good old college try, well plotted out, cobolt is an excelent choice.
Best of luck, remember "if" you try and break off an easy out you will think that stud was soft.

Regards

[SCWDP911]

Dang Don, that sucks. This car apparently does not like you. Maybe you should paint it a different color (Shane ducks for cover)

Hope it turns out your way. Any chance you are going to the PCA Sonic cruise in tomorrow night. www.pca-msr.org

I was going to try, but then found out I need to be in KY tomorrow for business. Have to see what time I get back.

[don gilbert]

succsess! after aprox 9 HOURS of drilling, got a hole big enough for a large extractor, and got one out. but, the new stud feels a little wobbly until about halfway in, and it worrys me. i know the 2.7 can be timecerted, can i do it to the 3.0sc engine too?

[don gilbert]

started on the second one, what a pain, i wish this on no one. If i didn't have the engine out and on the stand with my brother helping me, this could have turned into a disaster. before we ground the second down to drill, figured we would try and weld a nut on again, put a cool pack on the stud and a little heat to the case, came out about half an inch before it got tight, babied it as much as we could before it snapped, what a let down. time to mount the press back on the block and more drilling and bits.


thanks for the kind words Shane, did you make it to the pca meet at the sonic Thursday?

[don gilbert]

round two

[David]

"a little heat" may be the problem. I use oxy-acetylene and bee's wax. At the least, I'd use MAPP gas.

[nocarrier]

When ever I am trying to drill out a stud I use left handed bits.

Sometimes the heat and the pressure of drilling alone causes the stud to spin out of the threads.

You might want to try getting a set.