studs broken in cylinder head...help!

[benc.]

in the process of take the engine out of my 98 obw,

 

the bolts on the exhaust manifold is so rusted on there i broke two studs in the heads.

 

has this happened to anyone? and what did you do to get out the broken studs in the heads?

 

Thanks

[idosubaru]

if you're getting the heads milled just let a machine shop get them out, they're equipped to take care of this in minutes.

 

yes, i've done it before, did an EJ25 this year. annoying. use heat and get some left handed high quality drill bits. start small, drill a pilot hole, then drill a bigger hole and eventually it'll back out.

 

or.....a method that others will ream me for suggesting is to drill a small hole inside the existing bolt, tap it, and install a smaller bolt into the old bolt...just leave it there (it's not going anywhere!). i don't recommend it, but i've done it and it does work. just be wise on sizing it as big as you can, drilling in the center and don't over tighten the nut, and you're on your way. actually removing them is a pain, but i've done that too (that's what i usually do).

 

there's lots of other threads on here about this...might want to search and look them up. good luck it's no fun!

[msmithmmx]

May I ask, were you using a impact gun?

[idosubaru]

May I ask, were you using a impact gun?

i wasn't. i don't think it mattered in my case, they were in there so bad there was no way they were coming out.

[benc.]

grossgary: thanks alot for the replies! I couldn't believe how rusted some of those bolts were, being rest of the car body seemed really good as far as rusting goes.

 

I am thinking about just taking it to the machinest and see if they can work some magic, or else im screwed.

 

btw, i wasn't using an impact gun, thought about it at first, I wanted to see if the repeated beating would loosen the rust, but i never got around to using it.

[idosubaru]

funny you say that, mine was the same way...vehicle was in great shape, not a speck of rust on it, but those exhaust bolts sucked worse than any i have seen to date.

 

anyway, if you're pulling the heads DEFINITELY take it to a machine shop, just not worth the effort in my opinion. you can get them out but it'll probably require some extra tools, lots of time and annoying. i wasn't pulling the heads on mine so i didn't have much of a choice but to extract them = no fun. turns a 5 minute task into a 3 hour ordeal including trips to the store, breaking tools, some welding, grinding...real PITA.

[2X2KOB]

If you have a stick type arc welder or a wire-feed welder, you can center a nut on the broken stud and weld it inside the nut to the broken stud, let it cool, and back it out. The heat helps break loose the bond between the stud threads and the hole, too. If the nut twists off, just do it again.