# Agghhh!!! Broken Exhaust Studs!



## Twanage (Sep 14, 2006)

I finally got around to replacing my leaky exhaust manifold gasket. 2 bolts came off successfully, the other 6 had to be cut or grinded off (Because the bolts were completely rusted) Hours later, I get the manifold off, but 2 of the studs are now snapped off flush in the cylinder head 

So I gather from other posters that I have to drill them out using a 90 degree drill + left hand bits. Does anyone have any tips to help me? Please help me get her back on the road:bawling: 





BTW: The guys in the local tool shops thought I was winding them up when I asked for left hand bits!! Anyone know of a good online tool shop based in europe?

Cheers guys


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## Twanage (Sep 14, 2006)

OK the Left hand bits will be here in a week or so, so I'll update and post more pics when I get a chance. 

Two things I now regret not doing:

1- heating the engine block around the studs with a torch before removal. 

2- using a proper 6 side hex socket. try as I may I could find only spline sockets for sale last weekend. (Probably why I had to cut off 6 of the bolts) 

Here's a pic of the old gasket verses the new one:


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## Twanage (Sep 14, 2006)

OK an update, I ordered the left hand bits, they'll be here by wednesday. I've been spraying pentitrant onto the studs every so often for the last few days to loosen things up.

Here's some pictures of the offending studs and manifold area...Gotta love the state of the studs 

I'll update when I drill the bolts out. Fingers Crossed..........


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## Scott ZHP (Jul 17, 2003)

Heat and penetrating oil are your friends on broken studs; heat it, squirt it, repeat. Center punch the stud remnant in the exact center and go slow with the LH bits. They often work the stud out from the twist/vibration. You may not want to hear this, but this can be a real chore. Good luck. Worst case, remove the head and take it to a machinist.


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## Scott ZHP (Jul 17, 2003)

Heat and penetrating oil are your friends on broken studs; heat it, squirt it, repeat. Center punch the stud remnant in the exact center and go slow with the LH bits. They often work the stud out from the twist/vibration. You may not want to hear this, but this can be a real chore. Good luck. Worst case, remove the head and take it to a machinist.

For the longer stud pieces, you may be able to weld a nut onto the remnant (after drilling the threads out so it will fit over the shank remnant).


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## Twanage (Sep 14, 2006)

Cheers Scott! I managed to remove 5 intact, with the help of stud extractors, mapp gas and oil/wax. 3 are snapped off flush in the block.

Just spent 5 hours trying to drill one of them out. Found it impossible to get the drill bit centered because of the location. I may have to dremmel the remnants of that one out


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## Scott ZHP (Jul 17, 2003)

Twanage said:


> Cheers Scott! I managed to remove 5 intact, with the help of stud extractors, mapp gas and oil/wax. 3 are snapped off flush in the block.
> 
> Just spent 5 hours trying to drill one of them out. Found it impossible to get the drill bit centered because of the location. I may have to dremmel the remnants of that one out


BTDT. To be honest, it may be less work to yank the head.


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## Twanage (Sep 14, 2006)

Scott ZHP said:


> BTDT. To be honest, it may be less work to yank the head.


I'm considering that at the moment. It's an 8 valve SOHC engine, so I reckon I could probably handle the complexity. What puts me off it the cost of tooling, gaskets etc. Oh yeah, also I have to work in the garden 

I've noticed that the valve in cylinder #4 is covered with white deposits, a bit like what you see on a 'lean' spark plug. The other valves are dark in colour. *Does this mean the valve is leaking?* I originally thought the exhaust leak was from the back of the manifold.....

I would probably consider pulling the head if I thought there was a good reason, such as a bad valve. *Would it be necessary to deck the head even if the original headgasket, etc are ok? *

Thanks for your help


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## Scott ZHP (Jul 17, 2003)

Twanage said:


> *Does this mean the valve is leaking?*
> 
> I would probably consider pulling the head if I thought there was a good reason, such as a bad valve. *Would it be necessary to deck the head even if the original headgasket, etc are ok? *
> 
> Thanks for your help


1. Maybe. Did you do a leakdown test? Compression test?

2. Not necessarily. But you will need a new head gasket. I don't ever recommend reusing one, although people do. It's false economy.


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