exhaust studs

[roasty_duck]

front exhaust stud on my new engine was broken, welded a bolt to the end so i could still use but hasn't worked great, the other stud has no thread left its been stripped..

tips on removing them? will drill if i have to.

also is it save to drill out and re-tap to and put an m10 bolt in each?

if so what mm drill bit do i need to go up to before tapping

[Pete.L]

Can you apply some heat and then twist it out with some mole grips, filing a couple of flats in the existing stud?
What about welding a nut on the end and then see if it will twist out. I Only drill as a last result. If you aren't sure about collapsing the thread and running a tap up it why don't you consider a 8mm drill bit and a Heli-Coil? Might save puncturing the water jacket.


Pete.l

[roasty_duck]

tried stillsons, tried welding a nut, no joy

[Steve97]

easy to take off the head and put stud in a vice then rotate the head, have done all the other methods and for me this is by far the best

[sirch345]

Some have found cutting off a section with a Dremel of a few millimeters of the thread boss (the alloy part where the stud enters the head) has freed the stud up.

I personally like to take a piece of flat bar, drill a hole in it near one end, place it over the stud and weld it on using an Acr welder. The heat generated from the Arc welder helps IMHO to release the seized stud. Once you have welded the flat bar onto the stud you have a nice lever to rock back and forth to release it, I still use a releasing fluid once I've finished with the welder,

Chris.

[tony.mon]

Your idea of drilling out to m10 will work, but the clamp plate on the header may be too small and weak after being drilled out to m10 clearance.
If you go down that route make sure the bolts are shorter than the hole length when tight as it will wreck the head if you punch a bolt through the end of the hole and puncture the water jacket.

[roasty_duck]

ill try get the studs out and see what happens.