The red circle is the hole in the manifold
The yellow circle is the position of the stud
The blue circle is where the new stud would start if I were to redrill and centre it

NOTE - The blue circle will become bigger as drilling begins, meaning it will be outside of the yellow circle's perimeter
Once drilling is complete the blue circle will be the same size as the yellow circle - but will be centred with the red circle as opposed to being in the same position as the yellow circle

 

Ok, hole number one is now drilled to the correct depth

Next question, in order to enlarge it from 5.5mm to M8 should I drill it again with a slightly larger bit, working my way up to a size where I can run a tap through it, or is there a better way to do this bit?

Thanks

 

Ant ,
The idea is to drill the stud untill your a thou away from the threads in the head, then with a sharp pick took, split whats left of the bolt and pull out the debris. However more often than not , unless your using a pillar drill and 100% centralised, I find you at best catch the threads in the head or even worse damage them so they either need re-tapping or an insert used.
From now on, I'm going to remove mine every two years and replace with new. I have always found for a top marque car that this problem is truly pish.
Good luck and I am watching out for every new post you make.

 

A new M8 needs a hole of 6.7 mm so go from 5.5mm to 6mm and eventually 6.5mm.
The speed of your 5.5mm drill should be around 1000 rpm. The speed for going from 5.5mm to 6mm should be 250 rpm / 500 rpm.

You will most likely drill a little off center anyway so you should be able to pull some material with sharp pliers.

 

Excellent, thanks Frank and Stef!

Frank, I replaced my fixings with stainless items
If you remind me when you come to replace yours again I'll let you know if they're worth going for or not

They didn't cost any more than a regular fixing, and seemed to be manufactured to a close tolerance

 

I must say that I'm amazed with the amount corrosion, and admire your willingness to attempt to fix this yourself. I would have passed on attempting this personally, as I likely would not be patient enough, or would likely cause more damage than good.

Hope you get this sorted, you will certainly be rewarded in the end, and likely feel even more connected with your car.

 

Thanks mate, the corrosion is definitely the worst I've seen on our cars
The climate over here is far worse than it is in the States, so I don't think many guys on here will see problems like this

The car has always been well maintained, and has just over 50k miles on it, but rust obviously doesn't know or care about that

The rust around the wastegate rods and linkages is just as bad if not worse - pretty much all the pieces in that area have corroded to the point where they now look like just one piece of metal now - you can't tell there are threads and clips and nuts there at all

I had absolutely no issues with drilling the manifold, as the worst I could do was scrap it, and manifolds are cheap anyway

I was a little uncertain about drilling the head at first, but once I got the "drill-bush" that Stef mentioned I was pretty confident again - you can't do anything but drill perfectly straight with one of those

I'm certainly not patient by any means
There's been a lot of shouting any swearing going on whilst doing this job

This 'easy' job has been such a pain I thought I should post all my problems on here just incase somebody else is unlucky enough to suffer the same issues

Hopefully they can see what I'm doing and can avoid the faults and get things resolved quickly and efficiently

 

Agree 100% with JSBear. You are a very patient man and this experiment will enable you to approach more difficult tasks in the future with a great smile. Good luck and thanks for keeping us up to date even in very frustrating moments.... Determination is the good word.....

 

Thanks, it means a lot to hear things like this,
This forum if definitely good for motivation, I would have given up if it weren't for everyone on here

I'm getting so frustrated with this job, I mean, it's just an exhaust manifold
It's not meant to be this hard

I've got one hole drilled to the required depth, it's only 5.5mm at present so I'll need to enlarge this as per Stef's instructions

My plan is to drill all the studs first, and then enlarge them afterwards

I can't believe how long this job is taking, but I think I can just about make out a very small light towards the end of the tunnel

I don't have much spare time though, so it's still going to be a little while before it's finished

One thing's for certain though - I'm not in any hurry to replace my exhaust or turbos now

 

Update, and a couple of pictures

In the photo below;
The lower hole was ok when I removed the exhaust
The hole on the left has been drilled and now threaded
The hole at the top still has the sheared bolt stuck in it - that one's my next job




Here's a slightly closer picture of the bolt to be drilled next

 

Well done Ant, just goes to show what can be done with perseverance.
Good luck with the next one.

 

Thanks Frank
I'm just stubborn really

The second one hasn't gone quite as smoothly, but I'll get it sorted

I started to drill this hole a little off centre - I've managed to pull it back now though, so we'll see what happens when I get a bit more depth to it

 

I'm a bit stubborn my self. Keep up the good work.

 

Who wants an update?
There's no good news today

Drilled through my water jacket
At least the garage floor gets a wash

 

OUCH!!!!!! I feel your pain I am so sorry for you. You've worked so hard....