help!snapped manifold stud

Post Wed Mar 28, 2007 7:12 pm

hey everyone, just preping my engine so its ready to be droped in the e30, but one problem - snapped an exhaust manifold stud flush with the head.

Ive drilled a small hole in it, so as to use an easy out, but it isnt happening!

Im not to happy about completly drilling it out - too much risk in my opinion of ruining the head.

Has anyone got any advice? BTW its an m30.
Cheers Alex

Post Wed Mar 28, 2007 7:15 pm

weld something to it?

Post Wed Mar 28, 2007 7:22 pm

good idea, but as ive drilled it already it is about 5mm into the head, so not sure whether welding would be possable. Help!Cheers Alex

Post Wed Mar 28, 2007 8:50 pm

when you say easy out do you mean a stud extractor, like a left hand fluted tappered drill bit thing that you screw in and it undoes the stud as you tighten it?

If you did'nt mean that they do work pritty well.

Post Wed Mar 28, 2007 8:51 pm

I would get it hot before even thinking about turning it out

Post Wed Mar 28, 2007 11:57 pm

yeh thats what i meant, basicly a left threaded screw. Suppose i need to get the heat gun out, im just a bit worried being an alloy head.

Post Thu Mar 29, 2007 12:08 am

Heat the whole head up, place infront of a space heater or similar then give the stud some more with a blowtorch before using the extractor

Post Thu Mar 29, 2007 12:12 am

DanThe wrote:Heat the whole head up, place infront of a space heater or similar then give the stud some more with a blowtorch before using the extractor

heating the stud more than head will cause it to expand and make the job harder....heat head up then work quickly to remove stud

Post Thu Mar 29, 2007 12:14 am

sams bro here, weld into hole nice and hot and keep building it up till it sticks out and built it up abit off centre then let it cool down abit normaly so metal isnt still soft, dont put water on it, use some pipe grips/stillsons? on the weld while its still abit hot and it should come out ive done 3 like this on m20 heads and loads of times on other stuff, you can use this method if its stuck in steel aswell but you need to use MMA/stick on anything smaller then 14mm really or you risk welding hole up

Post Thu Mar 29, 2007 12:16 am

gcorky wrote:
DanThe wrote:Heat the whole head up, place infront of a space heater or similar then give the stud some more with a blowtorch before using the extractor

heating the stud more than head will cause it to expand and make the job harder....heat head up then work quickly to remove stud

ally head will transfer the heat away from the stud very quickly and expand the ally around the stud more as ally expands alot more then steel and is much better condutor so any heating general area should work ok.

btw ive done this with head attached to block on 2 studs and the head was fine after no leaks from gasket atall.

Post Thu Mar 29, 2007 12:19 am

Technically yes, but in reality the heatsoak of the alloy will pull the heat out of the stud and into the surrounding area much quicker than you can spanner a stud extractor round

Thats how I have got crank bolts out in the past, when no impact gun will touch it I give the bolt a serious dose of blowtorch, when it starts to glow the air gun wiz's it out like its a nylock.

Post Thu Mar 29, 2007 12:20 am

bah! beat me to it

Post Thu Mar 29, 2007 8:04 am

there is some thing else i've just rememberd, we use it at work, called freeze and release made by lock tight its a spary that takes what ever its sprayed on douwm to around -40c we use it to get 35mm stainless studs out ove stainless blocks by drilling a hole down the centre of the stud and the spraying this stuff down and then using a big bar

Post Thu Mar 29, 2007 11:12 am

appletree wrote:when you say easy out do you mean a stud extractor, like a left hand fluted tappered drill bit thing that you screw in and it undoes the stud as you tighten it?

If you did'nt mean that they do work pritty well.

they also snap sometimes. and as they're necessarily rather hard (and brittle) they don't drill out very easily once snapped.

i'd never, ever use one of those in a cylinder head again!

welding is the way.

Post Thu Mar 29, 2007 3:33 pm

Another option if you are really confident and have access to a lathe is bolt the manifold onto the head so that the bolt hole in the manifold is dead on centre of the broken stud. Next machine up a guide bush which fits the manifold hole perfectly with a hole in it the core thread diameter of the stud. Place the bush in the manifold and drill through the bush into the stud, remove the manofold and if youve done a good job you should be able to pick the bits of thread out with a scriber. Alternatively you could make up a plate with a guide hole in it which mounts on a couple of adjacent studs. Hope this helps failing that a good machine shop will be able to do the work. If all else fails try and have the head Helicoiled they are stronger than origional, in fact we have some ally castings at work which come helicoiled from new. Matts Dad

Post Thu Mar 29, 2007 8:56 pm

basicly its broke!lol, drilled it, it will not come out, even with loads of heat. Im going to drill it totally out, and re tap an oversize thread and oversize stud. Its not good, if it fails its time for a costly head removal and rebuild. Not what I want to do!Cheers for all the help everyone Alex

Post Thu Mar 29, 2007 9:42 pm

A method I've used in the past is to drill a small hole by hand near, but not quite in the centre of the stud and right through.
Gradually increase the size of the hole until it cuts partly through the threads at one point on the circumference. Hopefully, with a bit of teasing with a small screwdriver, you can collapse the crescent formed by the remains of the stud in on itself slightly, and wind it out.