How to remove a sheared header stud

[SoonerYFZ]

A buddy of mine has a 400ex and wanted to take the exhaust header off to clean it up with steel wool. When he was loosening the nuts that hold the header onto the front of the engine, one nut became very tight and he continued to apply pressure until finally the stud sheared off along with the nut, with about a third of an inch of the stud remaining still protruding.

After trying vise grips to try to get the stud out and failing he finally took it to a welder and had the guy weld a nut onto the remaining stud. Once that was done, he tried to loosen the stud and remove it so that he could put in a new one. The stud loosened a few rounds then froze again... and once again it sheared off, this time flush with the engine. The welder wouldn't try it again for fear of damaging the head due to the heat of the torch.

Since then we have tried using extractor bits in conjunction with PB blaster penetrating lubricant and the extractor bits have snapped twice. This stud does not want to come out. Thats how it sits right now and aside from taking the engine apart and trying to remove it from inside we are at a loss. My buddy is afraid to drill out the stud for fear of damaging the engine head but I don't know what choice he has.

Does anyone have any suggestions on how to remove that stubborn stud?

[Spikers400]

I snapped a bolt for my head cover. I did the same thing, also broke 2 extractors. I wouldnt worry, take it to a machine shop. He can probably drill it out or put a bigger stud in it, or put a coil in it. I got mine back in a day. And it was cheap. Good luck

[deathman53]

next time use a torch and heat up the nut before you try to take them off, and do the same when you snap them and weld a nut on to try and remove the stuc (heat up by the head, a map gas or propane torch won't hurt it)

[PhilMoore]

You would think the welded nut would have heated up the stud enough to loosen it. It sounds like it did, but when it got really hard to turn, he should have either heated it back up, or actually screwed it back in a few turns.

I heat mine up until they glow cherry red before I even touch them with a wrench. Also, if they begin to bind again, I screw them back in, and keep working back and forth until they come off. If it starts to bind, don't keep twisting and force it.

As for your current situation, a welder should be able to lay a nut on there and get it welded so you can get it out. Otherwise, you will probably have to take it to a machine shop and get it drilled out, and new threads put in. Don't try to do it with a hand drill, unless you are really good. You need to drill it straight to cause the least amount of damage to the head.

Most people don't know it, but there are left hand twist drills available. These drills work counter-clock-wise and I have used them a few times. They actually work like a screw extractor and back the screw out as you are drilling, saving a lot of time and aggravation. It does not always work, but when it does it is a real time saver.

I highly recommend you have a pro do it at this point. If you break off a drill or an extractor in there, you will really be in for it.

PS, I got my left twist drill at my local Fastenal supply (www.Fastenal.com)

[jjthekj]

Happened to my buddy and I too. Luckily we have a good friend that's a machinist. Have to say that's the way to go. Good luck.

[SoonerYFZ]

For some reason my buddy is hesitant to remove the head so that a machinist could help. I guess he thinks he will "have" to do engine work since the head would be off.