This is true, but on my "test platform", the stud is broken near the case, below the fins :)

Just found an old, but very interesting thread containing some ideas related to this special tool project:

http://forums.pelicanparts.com/porsche-911-technical-forum/262048-look-what-i-found-changing-valve-cover-gaskets-today-2.html

I was on that thread.

Newfie sent me a PM asking about my idea. I couldn't remember it at all. Now that I read that in retrospect, I can say I've always been a dreamer. ;)

Listen to Grady in that thread.

Thanks Zeke / Milt,

Yes, Grady has some excellent points, but I am a dreamer too ;), so I will continue to work on this special-tool-project, but acknowledge that engine removal + top-end rebuild is Plan A.

Cheers,
Tom

An interesting post I found in an old thread ( http://forums.pelicanparts.com/911-engine-rebuilding-forum/587739-driving-1-broken-head-stud.html)

As posted by cole930, removal and replacement of broken head studs with the engine still in the car! :D

AWESOME!!! :eek::D

A new plan is emerging from the last post ;)

No-go for me, but I think something like this could work...
 

I just found that my forward-most lower head stud on the driver's side is broken...it's probably been that way for a while from the looks of it.

After reading this and other threads about tools and techniques to try, I drilled a hole in the end of some 3/8" round stock...I was drilling with a hand drill and a vise, so the hole was very far from perfect (even broken though the side towards the bottom of the hole as there is barely any room left in the diameter of the rod one the hole is big enough to just start slipping over the non-threaded portion of the broken stud).

I gave it a try, and it failed to remove the stud, but I was surprised to see how much torque I could apply to the broken stud before the tool would slip slightly...even with this VERY crude desgn and attempt. I had a good sized pipe wrench on the flats I machined in the other end of the rod, and I was able to really lean on it before it slipped, and the slippage was very slight and "predictable"...nothing like the tool "stripping out". I did use a heat gun on high for about 15 minutes to try to melt any Loctite and I even used a propane torch carefully to try to heat that area of the case a little more, but I think this particular stud is just really in there.

I think with more careful machining of a tool like this, especially with any additional gripping mechanism, and with good application of heat to the case, there would be a good chance of being able to remove a decent percentage of studs...someone with a drill press or a lathe could make these easily for people to try as a cheap alternative one-time-use tool with very little to lose before having to do a top end tear down only for broken studs...

The press fit of this crude tool was so good, and all the way down to the engine case, that I considered cutting threads into the other end and using it as a "replacement" stud. It would not have torqued anywhere close to what the regular studs would have, but I think it would have helped with any tendency for the cylinder or head to "slap" at all since the other 3 studs are still tight...this could be another route to consider for people who have only one stud broken on a cylinder...the tool could be made just to press fit onto the stud remnant without any idea to unscrew the broken piece, and some sort of good epoxy within the drilled recess might make the bond even stronger for this temporary repair...just to minimize any "slapping" that might cause further damage until a proper repair can be made...

Olivier

Regarding the idea to use a 1/4" drive socket between the engine case and the start of the cylinder cooling fins, I could not get anywhere close to making that work...there is barely 1/4" of space there, and cutting the stud there would leave nothing to get a grip on and I still couldn't get any type of socket in there...

Standard 1/4" sockets won't fit through the holes in the cylinders, and I tried several brands of sockets, looking for cheaper ones with thinner walls and smaller overall ODs, but nothing would fit. I think the example mentioned was on a 930 engine, so maybe that's a different design at the the base of the cylinders, or maybe it's because my broken stud is at the far front of the engine, but there is no way for me to slip any type of tool onto the stud between the lower fins on the cylinder and the engine case...

Hi Olivier,

Excellent progress - thanks for posting this :)

Do you have any images of the tool? I have read that LOTS of heat treatments are required to break the Locktite + maybe even some PB Blaster, so keep trying!

Yes, I have often wondered if a temporary replacement stud could be locked onto broken stud by threading, welding, or epoxy - it's worth a try me thinks :cool:

SmileWavy

Hi again,

I have not tried this yet on my SC, but I will check it out soon and advise, with images. I did ask about any differences between the 911 and 930, and was advised that they should be the same. I do know that the engine tin has to be removed.

Many out there think this is insanity :eek:, but there are almost as many who think it is a worthy cause - perhaps I'll start a poll ;)

Safe Motoring,

Tom

Update
 

Hi all,

An update: This summer I continued to drive the SC occasionally, but recently the engine developed the tell-tale "sharp tapping / playing card on spokes" sound that usually indicates that the head is now loose to the point that damage is starting to occur.

So, I have now parked the car, and I am going to drop the engine soon. Once the engine is out, I am going to test various means to extract the broken studs without dismantling the engine.

I'll keep you posted, with images, as this unfolds.

Any new ideas out there??

Hasaramat,
I would like to thank you for this ingenious idea! To all the nay sayers and non-believers out there, this tool, at least my variant of it worked like a charm. I had the engine out to repair a couple oil leaks and to my surprise when removing the oil cooler the forward exhaust stud on #6 dropped out. Remembering I had seen something like this in the past I turned to pelican for advice and found this thread. What I did was took a piece of 3/8 steel fuel line (pretty close ID to stud) and cut just like this. Heated the case and base of stud a couple times, worked the "tool" over the stud and carefully
removed, took about 2 hours total, an hour of which was pondering how to make it work.

To all of those who will be informing me this isn't the preferred method, yes I am well aware, this will buy me some time to plan for top end rebuild.

I"ll be posting some pics a bit later tonite or tomorrow for anyone else in my situation.

Thanks again!!!

Thank you for posting this. How do you go about cutting a spiral or whatever that cut is called? I know it needn't be with lathelike precision, but still - how? Looks like a fine option to me - fix what broke.

You have, I trust, figured out how to install the replacement. If not, I'm sure you will ask.

Walt,
I took a piece of 3/8 Steel fuel line and cut it with a conventional cutoff wheel, slid it over the stud and grabbed on with vise grip and turned out. Had to work with it a bit because ID not exact as Stud OD so I bent tip over a bit so grabs on the end, rest is physics, heat base of stud and remove slow and steady. With old stud out I have 2 ordered, 1 dilavar (as replacement not to fool with differing metals) and 1 steel to make a tap to run in and clean threads. For new stud install I plan on cutting a slot in the end of the new stud and screwing in with flatblade screwdriver...again not preferred method but my choices are somewhat limited with motor assembled.

Another good piece of information on this subject is leakdown results, last week for kicks I plugged in my trusty leakdown tester and got 3% on all cylinders except for #6 which
was 4%, the loss was through intake valve not head gasket. This proves to me the hole is in relatively good shape (along with the other 5 cylinders) and nothing needs touching at this point.



http://forums.pelicanparts.com/uploa...1355873069.jpg
http://forums.pelicanparts.com/uploa...1355873173.jpg

Doh you should have said something about needing an extra stud before ordering a steel one to sacrifice. I removed 24 dilivars from my motor last rebuild and used two for thread chasers!

To install studs where clearance is limited, take a discarded barrel nut. Block its end below the inhex (I've used a nail through a hole drilled radially, though welding something in should be better. Since it will stop after a few threads are engaged, it can be used to turn the stud down into the case. And it should unscrew easily enough for extraction.

Varations on this theme would involve welding a plate between two junk nuts, making a bottoming nut system at the end of a tube, plenty of options. All, perhaps, better than a flat blade screw driver slot for work on intact motors where choices of stud installation are limited.

Walt,
I like the idea of the barrel nut with something for it to bottom out, I'm thinking the factory installed loctite is gonna be a little tight for a screwdriver, have been pretty busy with other things this week so this project is temporarily on back burner. I'll keep posted on how things go once back together.

KTL
Thanks for the offer but I just grabbed a steelie with the 1 dilavar(helped reach that $75 free ship threshold)

Hi all,

Any updates or new ideas out there on this subject?