4.6L exhaust studs STUCK

[TheCrowdPlow]

Tale old as time, Ive got 3 broken exhaust studs, all on the back ports. They all were/still are broken off above the surface of the head, about 7-9mm. They all were longer and I've consistently just kept shearing the studs shorter and shorter in the process of welding on nuts and trying to turn out.

So far Ive tried:
Letting soak with WD-40 (as I'm making this post its soaking with some CRC 5-56
Using a stud extractor, stud way too tight, stopped before I sheared the stud.
Use a propane torch to try heating the head around the stud, and then other times try to heat just the stud
Welding on nuts letting cool naturally, and also quicker with WD-40 or ice cubs, just shears the stud shorter, yes the stud is shearing shorter not "just my welds".
Heated the stud with oxy acetylene torch (made a plate to protect the aluminum head from melting)
Finally use a battery and jumper cables to make a short circuit through the head to the bolt.

NOTHING, all 3 studs havent moved at all. I need to mention that I noticed with all 4 heating methods I could never get the stud red hot more than just 3-4mm down from the tip. When welding the nut could be red hot but the stud maybe 3mm below the bolt is not red, not even started to get red. With the oxy acetylene I could make the tip of the stud start to melt, but same thing, about 3-4mm below the tip of the stud, its not even starting to get red hot. Most shocking to me is while short circuiting the stud with the battery and jumpers the bolt would NOT GET RED HOT. By time I carefully took the jumpers off the bolt and put it on the ground and reached back up to the broken stud, I could grab it with bare hands. The tips of the jumpers were white hot, smoking, melted the lead posts on the battery and it would NOT HEAT UP THE STUD.

Ive came to the conclusion that the stud is not getting enough heat were it needs farther down the stud where all the corrosion is.

How do I get these studs out? Any tips on how I can get actual heat into these studs? Only thing I can think of to still try is draining the coolant making the aluminum a worse heat sink.

That or use a hacksaw blade to cut the stud as short as I can without damaging the head surface and try welding again? This way the heat will be a lot closer to where the corrosion is? I dont want to resort to this cause I can still grab all 3 studs with needle nose vice-grips. that and I noticed on one of the studs I actually deformed the aluminum just around the stud a little from the intense heat welding the nut on.

Are these engines could that good at being a heat sink with the aluminum heads and block?

Im kinda down bad, I just wanted to install my longtubes and now Im a week into it. Please somehow help me.

 

[golkhl]

If the CRC does not work, I have had good luck with pb blaster. Also found these specialty tools on Amazon.

 

[TheCrowdPlow]

If the CRC does not work, I have had good luck with pb blaster. Also found these specialty tools on Amazon.
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Ya I just dont wanna have to resort to pulling it, its damn tight in there, a 90 degree drill might work.

 

[86GT351]

Ya I just dont wanna have to resort to pulling it, its damn tight in there, a 90 degree drill might work.

The whole key to drilling if needed is a steady hand!

 

[Pentalab]

What works WAY better than WD-40 or PB blaster is ....... a 50-50 mix of acetone and automatic transmission fluid. Like 5 X better.

 

[TheCrowdPlow]

What works WAY better than WD-40 or PB blaster is ....... a 50-50 mix of acetone and automatic transmission fluid. Like 5 X better.

I know about the 50/50 mix, the reason I didnt try that is cause the motor is still in the car and the stud obviously point downwards. So I dont know how I would be able to keep the 50/50 mix from just flowing off the stud like the WD-40 was doing.

Today I got some Aerokroil and am gonna keep spraying that on the next couple days. I noticed with both the Kroil and CRC when it is sprayed on it doesn't just flow off like a river the way the WD-40 was doing.

 

[Iceman62]

Easy fix...IMO...pull the motor.

With all the time, frustration & effort you've already invested, you'd be done by now.

 

[Rick Simons]

Stick with PB Blaster, and try using a pneumatic impact hammer (with a blunt tool) on the end of the stud to make it vibrate. Hit it straight on the end and at a slight angle, but not hard enough to break it. If you can induce any vibration into the stud it'll let the blaster seep in between it and the head material so the blaster can work its magic. It's amazing stuff. In almost every case where I've had a situation like yours, tapping/lightly hammering the offending object while soaking it with blaster works much better than just spraying it or heating the surrounding metal.
The aluminum of the head is gonna suck any heat you put on the stud right out of it, unless you can heat the entire head (obviously not practical if it's on the car).

 

[Joe Montes]

CRC makes a product called Freeze Off. I used it on a rusty/stuck exhaust manifold to down pipe nut. It worked where the penetrating oil didn't do anything. You spray it on the spot for 20 seconds and tap it with a hammer. It freed the nut.