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Removing exhaust header bolts - who to trust

trig_112

Well-known member
Joined
11 Apr 2014
Messages
175
Evening all,

In my last service they said my exhaust nuts and bolts were corroded so today I thought I would remedy that and swap my coils.

What they should have said is not they were suffering from corrosion, that the only thing holding the system together is hopes and dreams.

I'm missing 4 of the cat nuts and even 2 of the studs. Overall an 80's Ford looks at these fasteners with sympathy.

I then reached around to the bolts holding the headers to the cylinder head and began to with I hadn't.

Now, I'm man enough to have a go at most things but not replacing what is left of these bolts. I fear the worst, they will all probably need drilling out.

Who is the best out there for me to take it to? I read somewhere once upon a time that Hartech have a nice jig for dealing with broken bolts. Should I ask them to do it or is there a safer pair of hands out there?
 
Any decent mechanic.
 
The bolts aren't as straight forward to remove as you think.. A steel bolt in an aluminium head makes it easy to mess up if you don't get the drill in the perfect spot.. The jig you talk about makes it virtually impossible to drill the bolt in the wrong place.. You do need at least one original bolt to come out so the jig can be mounted on the head.. Most good indy's will have one so it pays to shop around if you have the time.. Good luck
 
I'm a decent mechanic and I know good mechanics, none of which I would trust to take a drill to my cylinder heads.

All the cat/clamp/mount nuts & bolts aren't a problem, its the cylinder head ones and I'm not willing to let anyone with 'a drill and a steady hand' have a go at the heads when a few quid extra gets a proper job done.

I will give the usual indy suspects a ring on Monday to see what sort of responses I get and hopefully a couple of recommendations will come in here.
 
Hi Trigg
have a read of this,
http://911uk.com/viewtopic.php?t=110603&highlight=
i beleive member popopbangbang has a jig he is willing to 'loan' out, have a read anyway, it is relavent to you, and he is selling titanium bolts to 911UK members.
I got A4 stainless bolts from a place in germany off ebay,
(eBay item number:361324244474 3xbags of 5bolts M8X25mm flange bolts £13.49 delivered)
their web is www.screwsandmore.de, great quality and delivery speed.
hope this helps :thumb:
 
Judging by prior posts on this topic, this can be a big time-consuming job that's probably best handed over to a good Indy that has facilities such as burning off stubborn nuts and the jig to remove and replace broken studs.

It can easily turn into a full-day job at an Indy. Think what that might cost at hourly labour rates of £70+VAT.
 
My mechanic has done mine and Endex on here too. Definitely not a DIY job and forget about the likes of OPC being capable of it. Like I said a good mechanic with a bit of nouse, an oxy-acetylene torch and some other bits of kit should be able to do it.

My mechanic is only 29 and managed to get every single bolt out without use of a drill, jig or other metal cutting tool (apart from a tap to clean the threads out) with mine.
 
Every bolt simply came out Alex? If so then you have been very fortunate indeed as it's certainly not usual. It's very easy to damage the threads, if that happens then ideally a time-sert can be installed which not all mechanics will carry. Its good to ask how the job will be tackled.
 
ras62 said:
Every bolt simply came out Alex? If so then you have been very fortunate indeed as it's certainly not usual.

I never said they simply came out!! It was a very slow process of heat up, cool with water, heat up, cool with water and an 8th of a turn back and forth each time. Well into double figures on labour but every bolt eventually came out, although some snapped and had to have nuts welded on in place of the heads.

Like I said - any decent mechanic, but I suppose what I class as a decent mechanic and what other people do are two totally different things. It's all about patience and skill.

Read my write up on it here: http://911uk.com/viewtopic.php?t=97853
 
Those original bolts didn't look that bad, Ive seen much worse. Still 20 hour is a major undertaking. The new manifolds are good value.
 
Believe me, the photo you see in the post is of the best bolts. The worst didn't even have flats on. But it's not what the look like on the outside, it's how they've fused with the aluminium on the inside. They key is to start breaking that fusion down by expansion and contraction until eventually they're able to be wound out. Fortunately my mechanic did me a massive discount on the labour so it wasn't too bad, but I have peace of mind the job was done without any detriment to the aluminium heads.
 
I have a jig you can borrow in return for some beers. Includes double hard bastard drill bits capable of getting through 20 year old work hardened bolts with ease.

I used this on mine to remove what was left of my original 270K mile old manifold bolts as they were absolutely not coming out any other way.

Trying to do it any other way i.e. without a jig will just be pain. If they're not too bad then it is entirely possible to chop the heads off, remove the manifold and weld nuts to what is left.
 
Cant talk for all OPC but the labour invovled is usually too high for the mechanics to do it and they dont really have the equipment , we used to call out an engineer from a local company to drill out pretty much any bolt.

But when you think of the OPC labour rate its far better for them to sub contract than waste their mechanics time on it.

I would have thought most Indys would have the tools to drill them out and i have to say the jig makes life a lot easier , as do the correct drill bits .
 
This was a job I was going to attempt but I gave in to the nagging in my head and took it to my local garage. Not a Porsche specialist but I trust the mech's in their.

They got every single bolt out without having to resort to a drill.

Although the mech who did it had the next day off ill due to a headache from looking up and working on it.

But all done and no more worries.

Shaun in Norfolk.
 
alex yates said:
Believe me, the photo you see in the post is of the best bolts. The worst didn't even have flats on. But it's not what the look like on the outside, it's how they've fused with the aluminium on the inside. They key is to start breaking that fusion down by expansion and contraction until eventually they're able to be wound out. Fortunately my mechanic did me a massive discount on the labour so it wasn't too bad, but I have peace of mind the job was done without any detriment to the aluminium heads.

Alex's mechanic did an excellent job on mine though he did concede that mine were much more corroded than Alex's. 3 came out with expansion/contraction and the others snapped so he had to jig and drill out. 20 hours labour but a job well done that I'm sure would have resulted in new heads if done at an OPC. I too had stainless steel bolts fitted like Alex so hopefully I shouldn't have the same problem in future.
I'm pretty sure this will be common on most early 996s and judging by the number I hear around with blowing manifolds it's a widely ignored fix due to risk and potential cost.
 

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