Exhaust manifold stud bodges please

[skippymoss]

When replacing my exhaust for a new Brickies stainless one (mmm shiny) one of the studs on number 3 cylinder broke off flush with the head
I sent it to the local engineering place for a helicoil
Then found that it had actually broken off some time ago - someone had previously tried to use a stud removal tool.
They failed and broke that off inside the stud
This means that it can't be drilled out (it destroyed one of those super hard drill bits whilst trying)
So we gave up, bodged it with a load of exhaust putty and left it hanging on by one nut - which was OK for a while
Now all the putty has fallen out and today the exhaust is blowing like a good 'un again

Options I can see are;
1. The engineering place offered to grind it away, build it back up with ally weld and then helicoil it - loads of ££££
2. Get a new cylinder head - plenty of ££££, and run the risk of the head bolts snapping and needing a whole new engine - mega ££££

Don't really fancy either to be honest

So any ideas for bodges that would be better than the exhaust putty/ one stud method tried so far?
The end of the stud had been bodged and hung on (at least weakly) the for the last 7 years before the old exhaust came off but I don't know how.
Welding?, chemical bonding?, industrial adhesives?, chewing gum and gaffer tape? - what might work and what probably won't please?
(Already tried chewing gum and gaffer tape - not brilliant)

[Aidan]

weld a new head onto the remains of the stud and extract it, clean up the threads or timesert if required and fit new stud - pain to have to take the exhaust off but this method usually works, clean out the drilled hole and you should get decent penetration

[skippymoss]

Hi Aidan,

Thanks for the reply, sounds like a plan and a permanent fix too which I would like.

However 2 (maybe daft) questions;

1. If the stud has broken off flush with the head what is there to weld to?

2. Is a welded stud stronger than the original stud? I.e. If the the stud was so tight in the head that it broke the original stud and also an extractor tool, wouldn't the turning force required to budge it just shear the new weld?

(As you can tell I'm a newbie so set me straight please)

[Aidan]

with the mig the weld will be to the stud, rather than the head which is alloy, you can build up a head bit by bit, the heat you put into the work will help to free the bound threads, as long as you get decent penetration into the remains of the studd then you will have a head which should stay attached and with some molegrips you can unwind it

[CovKid]

It would appear to be your only option without removing the head, putting it on a bench and seeing what else can be done - ie like cooling one component and heating up the other for instance. Unfortunately you have limited options with such a cramped space in which to work.

[skippymoss]

Thanks Aidan, I get the idea I think
Got access to a MIG - will have to find a weekend where it's not blowing a gale as I'm working outside!

Covkid,
Cramped is right - worth a go though I reckon - head removal makes me think of all the other things I could break in the process

Would love to get it sorted as it's a shame to bodge an expensive item like a SS exhaust

Cheers chaps

[Rich Tea]

Good luck with the welding method, I hope you're sucessful, I fully appreciate why you want to do it in situe if possible.

If it ends up as a bench job, you could get the stud EDM'd out and retapped oversize, either for a helicoil, a timesert or I think Heritage sell a stud which is 10mm on one end and 8mm on the other end.

Cheers

Rich

[kevtherev]

I had this happen on a motorcycle engine head
I was cleaning the threads after a shot blast and *tink* the dang thing broke off..

I had it spark eroded away, an aluminum weld filled the hole and it was drilled and tapped.

[skippymoss]

Spark eroded? Not heard of that before.
Self explanatory I suppose though?
Sounds like an engine out thing?

[kevtherev]

not a common thing I suppose but here in the midlands it's less uncommon
wire eroded, die sinking, or spark machining are other names

and yes engine would have to be out

if you really need to know...http://en.wikipedia.org/wiki/Electrical ... _machining" onclick="window.open(this.href);return false;

[Aidan]

obviously welding in engine bay esp if petrol then fire prevention and cure required, ie muckle fire extinguisher in attendence, two pairs of eyes good and if any signs of fuel leaks don't and protect the pipework/carb/air intake etc from splatter

[Mickyfin]

Some good advice in this here thread. I have been searching around for exhaust manifold access, and photos as I have now got a blowing exhaust, and its only evident under load, which points to one of the manifolds.

I know what im looking for, soot deposits from said blowing manifold, but I would like to know how to access them? Do I have to remove anything to access the manifolds?

[Hacksawbob]

No you can see them from under and engine bay but access is really bad the bend in the pipe restricts socket use on some of them. The bolts also hold on your pushrod cover plates you can feel and hear the blowing exhaust and if you get some one to pressurise the exhaust tail pipe with a rag (temporarily), you will hear it hissing out (possibly from more than one place). Assume that unless your exhaust has been off in the very recent past then you are going to have issues getting them out. Penetraing oil/heat etc not a pleasant job and in an inaccessible area with petrol nearby. Also as the standard fitting is studs you cant drop the exhaust without splitting it or cutting it You can replace the studs with bolts all the way around. I fitted tungsten bolts (not cheap about £30?) and put them in with
Duralac to reduce the likelihood of bimetallic corrosion. (alloy vs tungsten so unlikely)

[Mickyfin]

Thanks, I have indeed been underneath the Syncro today, and its not blowing from the exhaust manifold, but is blowing from a hole in the rear silencer, and the pipe running up to the manifold on the right hand side of the engine.

I can temp fix these of course, but the route of action with my OCD is to replace the whole system. Just need to save the pennies now I guess, or sell some unwanted items to raise the cash.

I have checked on Brickwerks, and Just Kampers, and they are not cheap are they? I think Stainless would be overkill, but will try and source nearly new/used if any come up for sale.

[skippymoss]

Finally found someone who could get this sorted for me today. Drilled around the remains of the stud. Little "bar-steward" came out in the end. Turns out the hole is a lot deeper than the stud. Tapped about another 10mm. Screwed the stud in. Filled around the drilled bit with metal filler stuff. Seems to have done the job. Top bodging!