Broken Head Stud Flush with Case
 

Hi guys,
The nightmare continues. I pulled the engine to remove the broken lower head stud. While there removed all the lowers as I did not trust them as I was doing this one sheared off right flush with the case.
So question is can it be drilled out, note have already blunted carbide tipped bits trying so guess the answer is no.
So next I guess is EDM removal if I go this route will it come out clean? The broken stud is on #5 rear most.
I am tempted to just replace all the ones I got out rebuild and drive with one missing but really dont want to do this as I will probably cause even more damage!

Do it right. Going on the cheap to save a few hundred will end up costing you a few thousand when you destroy something.

It is a major ball buster I know. When I bought my ported/machined heads they came with the old exhaust studs still in them. Youd think for 2250 he would change them... So I have the jig, and 4 have snapped off. but done right is the best way. I have no choice as I have thin flange SSI's so the stock 50mm studs wont work.

You need titanium bits not carbide at a minimum. Buy one of the $9 bits instead of the $4 dollar ones and see if it makes a difference. Depending on what you have it may be difficult.

We have removed them like that by grinding a bolt to a blunt point and tig welding it to the broken stud. Then heat the case to release the licorice and have backed them right out. It works very well.

EDM is the best route, and yes it will come out clean.,cheers.

An EDM machine will take it out cleanly but very expensive and a last resort in my opinion. Try either what Turbo nut suggested with the bolt, or I have set a nut over the broken stud and welded the inside of the nut to the sheared off stud, the heat helps loosten the stud and you can just spin it out with a wrench or socket. This has never not worked for me (and I had access to an EDM)

If you have rounded off the carbide tipped drill bits it is most likely not running them fast enough. Carbide tipped or solid carbide drills will drill through much harder material than regular HSS or TiN coated drill bits, they just need higher speed and are much more prone to chip.
Titanium Nitride is only a coating that is added to regular HSS or cobalt drill bits to reduce some friction and heat, a quality set of uncoated drill bits is better than a cheaper set of TiN coated drill bits.

Just my $00.02

A left handed drill bit might help here. As it drills it will tend to
unscrew the stud and you might be able to back it out that way.

andy

Davie, You re getting a lifetime worth of experiences with this engine.
Bruce

Ok so today carted the long block to a good local engineering shop they tig welded a bolt to the stud and it backed out with minimal effort. So tomorrow on to cleaning up and re-assembly woohoo....

Cool (or Magic) as you boys would say down there, glad to hear it worked.

Quick update got the engine back in the car today and she fired right up first turn of the key. When I did the cam overlap this time set it at 1.38mm both sides vs the 1.29 I had previously, it seems to have made a difference to the low rpm driveability of the car she seems much more responsive at low rpms now than before. Oh and I also had a few small vacuum hose leaks which have helped. Car is running strong and appears none the worse for the head stud debacle....

Congratulations Davy! After all that aggravation it must feel great to be back on the road.

I did a 3.0 8.5 CR and the settings was 1.68 and 1.7. Makes the low RPM more responsive.

Bruce

[QUOTE=Daviboy;5847548]Hi guys,
The nightmare continues. /QUOTE]

Look like its finnaly over... Happy motoring.

Bruce well that will explain that then mine is a 9.8:1 3.0L with 964 cams as I am sure you are aware. Have heard so many people give this set up a hard time but hey it works for me. My car is not a track racer just a graceful old lady whom I want to see survive another 150,000 miles so she will be driven with compassion and care with the occasional foray into the the higher rpm's....... so today is detailing day its gonna be hot 30 deg C so will spend some time falling in love again in the garage, just know the wife is going to love that :rolleyes:

I'll trade you... Nippy -17 deg C :)