superloaf

I have two broken exhaust manifold studs on my 951 and need to remove them so I'm wondering if there's enough clearance to use a 90 degree drill? There is about 5 inches between the head and the body; I believe most 90 degree drills are a little more than 3 inches so with a drill added, it's getting close. I'm sure it's tough and tight clearance but would just like to know it's possible.

Please let me know if you've done this or used some other tool/method to get the broken studs out.

V2Rocket

Google/search yellow pages for an "EDM removal" shop...
I used one down in Orange once upon a time for a snapped off coolant-jacket bolt on a 944.
Pricey, but super quick and clean job done.

superloaf

Thanks but I'm in Nashville now. I'll check here.

How much was it?

V2Rocket

$175
but that was their minimum/set up cost.
Doing up to 8 studs this way isn't going to be any more work than just 1...EDM is amazing.

superloaf

Arrrgggg, what a misery this whole process has been. Let me tell you what I've learned:

Ok, forget the expensive 90 degree drills. Lowes has a few 90 degree attachments for any drill. Two are made by DeWalt and a couple others by Milescraft. I used one of each. First I got the DeWalt which is very compact and works well except that it has a gooseneck which I eventually broke when the extractor grabbed. Also, the DeWalt is for hex bits which limits drill bits severely.




And it's only $25 too! I can't believe for all the research I did, no one ever mentioned any of these.

But even better was the Dremel I finally had to use to grind out all of the stud and the broken extractor! Traditional bolt extractors are pretty horrible especially if you don't have the special T handle wrench to use with them and which neither Lowes or Home Depot even sell. Nothing will grip these smaller extractors which only have a 4 sided flange the size of the tap. Anyways, used a dremel with a right angle attachment head and then many different cutters including diamond tipped (didn't work at all, just disintegrated), and carbide grinding bits of various shapes. I did get all of the stud and extractor out but I went through about 10 different bits. And I also damaged the aluminum enough to cause doubt in how well the helicoil is going to last.
Oh, you also have to drill for the helicoil which on the M8 stud is 21/64's (yeah, have fun finding these bits! Lowes did have them but they are tricky to locate.) Then I used a Milescraft Drill90Plus right angle attachment because it allows regular drill bits and not hex bits as you will never find a 21/64 bit in a hex! Of course the only problem is that the bit is way too long to fit between the fender and the head. So again comes the Dremel to the rescue. Using a cut off wheel that thing slices right through the drill bit.
Then drill, tap, and insert a couple of helicoils. Would have been perfect had I not buggered the hole in the aluminum but I think it will hold. I hope it will hold!
Then used rennbays exhaust manifold kit with the hex studs.

So now it's just bolt up the manifolds and drive, right? Nope, of course not. It's basically struggle with the 1 and 4 manifold for hours as it doesn't line up. Seriously, is there a secret to getting this thing on? The bolt holes are different sizes so there might be a specific order for installing the studs. Of course I've tried them but still no luck. I'm sure it's just one of those things where you just have to have it lined up perfectly and have some luck but still, what a pain. (This same line of thought has happened nearly every time I've tried to reinstall any part of the exhaust system on this car....)
So back to the struggle, I'm nearly finished though...Just as long as that stud holds...!

The offending hole/stud. Nope, you can't see it so have a mechanics mirror or you're lost.




And the finished product with shiny new helicoils. I put two in, stacked for maximum thread contact.

V2Rocket

By that point I would have pulled the head...
You are much more patient than me!
Be sure to have the 2-3 already hanging on the studs when you put the 1-4 on.

superloaf

Patient????. Ha ha, plus pulling the head would be another $500 in gaskets and seals (jesus Christ, I've never seen a car with so many seals and o rings and yet the stupid car still develops leaks just like all the cars without these parts!) and not to mention the cost to my soul and mental breadth and another two weeks of downtime. I mean if just an oil pan gasket is that much of a pain, I can only imagine what pulling the head would involve! I miss my Alfas! Quirky as they are and chock full of their own problems, at least they go back together decently. This Porsche was the opposite: pulling it apart was easy but getting it back together was such a horrible mess as nothing fit. My regard for Porsche engineers has been brought down a few steps, to where it should be as they are merely human engineers and not the auto gods I once thought.

V2Rocket

Pulling the head is a 2-3 hour job, get it refreshed and put it all back on in another 2-3 hours...

Head gasket kit is what, $150? Get the head refreshed for $250...

superloaf

Ha, yeah, right, and an oil pan gasket is $50 but that didn't stop me from spending close to a thousand on all those piddly seals and O rings and other broken parts which cropped up. And 2-3 hours? Maybe to disassemble but then 2 weeks for reassembly. And with my luck, the head wouldn't fit back on the block, ha ha.

And $250? I don't think that would go very far. I'm not doubting your expertise and maybe this would be possible but with this car's history, I wouldn't take that risk.

snb13

V2 is right

V2Rocket

Moot point now that you're done drilling.
But for future reference there are some shops around that I have had 944 heads rebuilt at for $250 or so. The one I have the most experience with is in Riverside. Another in Poway, another in Northridge...I've moved around a lot I have full confidence in their work and so do my customers..