Posted a message a couple of weeks ago regarding removing the ex manifold on my B230F w/400,000km. Re-assurance by all replies that no way will I bust a stud if i take care. Care I took, followed all the rules, torched them up orange..but..snapped the front 2 off flush in the head. The last 6 luckily came off with the studs still in the head nice, nice as i glowed them up real good!!
But now I have a larger problem than when I started.
Any ideas on drilling my studs out.
Am I taking my head off? Winter is coming and removing the head is not the answer i'd prefer.

Those studs are high strength heat treated steel so torching them wipes out
the heat treatment by putting them in the "normalized" condition, only slightly
harder/stronger than fully annealed. Should not EVER heat them beyond the
point where a clean surface begins to turn from straw to purple. The big
deal of heating things like that is to induce thermal stress and break down
the hydrated oxides, which can be done at about 250°F.

I'm not sure about the alloy the head is made of but all that torching may
also cause softening of the aluminum or even worse, eutectic melting of the
alloy around the stud, which is where you need the highest strength.

From the standpoint of overheating while operating, as long as the head was
full of water you probably couldn't hurt it much. Once the waterjacket side
of the combustion chambers and exhaust ports go dry, the rules change
drastically.

I wonder if a helicoil repair of damaged stud holes might be a good idea...
--
George Downs Bartlesville, Heart of the USA!

Sorry Kenn, but the chances of success when doing this on the car are not good. More chance of screwing things up worse.

I don't know what your tolerance for vehicle downtime is... it may be easier if not cheaper to acquire a junkyard cylinder head and just swap it on. I've done this... it was the two lower rear ones on an 89 240 head. No way of getting it done in the car. Not enough room and the angle for drilling is poor.

If the head is not overheated, it shouldn't need more than a good cleaning in order to seal up again. The head gasket is really not too bad a job, though of course it means removing the timing belt, valve cover, and so on.

A gasket set is like $40 from FCP. Removing and re-torquing the head requires a 1/2 inch torque wrench, a breaker bar, and a strong arm.

Drilling and re-tapping the head for new studs will require a lot of patience and a steady hand. And good drill bits. Get cobalt bits. They aren't cheap but they will chew those old burnt studs right out of there. Special left-hand drill bits are a big help with this job too. Start small, get the bit centered, and work your way up. Getting off-center or crooked can mean trashing an otherwise good head. You may just want to take it to an auto machine shop for stud replacement. Should be very straightforward for them. Here they charge like $10 for a replacement.

--
Rob Bareiss, New London CT ::: 92 244-M47-208K ::: Bilsteins, Turbo swaybars, Virgos, Lowered, Group A wing, Tach, 6-Disc, Satellite Radio, Keyless Entry ::: Coming Soon: B-Cam!

See the 700/900 FAQ for LOTS of advice on this very problem. Best to pull the head.