How deep can you drill the head (KADE) broken manifold stud

[alkemyst]

The front exhaust manifold stud broke on my KA24DE, the header is leaking now and sounds like crap.

The mechanic did a butchered job and doesn't want to drill it more (they widened the hole to accommodate a stud that takes a 3/4" nut...they just jb welded it about two threads in...needless to say it fell out. They insist they can't drill it deeper.

I never attempted a helicoil here. If I do pierce the water jacket in the head would the stud seal it?

I don't want to put much money into this as I am going to be pulling the engine out anyway next year.

Thanks

Å

[projectRDM]

Pull out another stud or buy a new one. Measure. That's how deep you can go. If I had one laying around I'd measure it but I'd guess it to be at least 20mm. I've pulled a hundred of them but never save them for some reason, my scrap guy likes the heads to be clean when I take them in.

You've got more room to go if there's only two threads biting.

[fueled by hate]

Why didn't you use an extractor set and pull the broekn stud out? Same shit happened to me and it took like 5 minutes to pull the broken one out and cost $4 for a new stud from nissan. Sounds like your mechanics name is Jerry Rig.

[alkemyst]

Why didn't you use an extractor set and pull the broekn stud out? Same shit happened to me and it took like 5 minutes to pull the broken one out and cost $4 for a new stud from nissan. Sounds like your mechanics name is Jerry Rig.

The extractor broke. The stud was seized inside the head. I didn't have what I needed in my garage to continue attacking this.

The stock studs only go into the head about 1/2-3/4 of an inch on my 98. Also just because one stud goes deep, doesn't mean another can.

I don't know why you needed to pay $4 for a stud from nissan...it's a common part in several inner and outer lengths.

Also it was a mechanic, not my mechanic. Regardless it has nothing to do with the problem.

[alkemyst]

just an update...the stud area is VERY shallow for the first stud. I just touched the water jacket. A helicoil will not seal so don't try it, just drill to M12 and go with an M12x50x1.25 stud...you can also find M12 to M10 studs to keep the same sized nuts across the header.

340 Mopars had exhaust studs that touched the water jacket and used RTV to seal. So despite all the posts online about RTV not working in this application, they must either have done something wrong or didn't actually try.

It's been a week and I am still good. Exhaust leak is gone :).

[gunluvS14]

its funny this post came up. I was in the same boat, I tried to extract the buried broken stud out (the very first one from the distributor), that failed. Also during the process, I might have touch the water jacket with my pilot hole, I don't know. My heart stopped a little at that time. The engine is on the engine stand, I poured a cap of water into that hole and the liquid didn't go anywhere, but that doesn't tell me if I actually drilled thru to the water jacket or not. We'll see.

So I dremel the rest of the broken stud out with carbide bit, and I used 1/4 length of the M10x1.25 helicoil, and I installed a new stud back on. Its not very tight, but I think its enough to keep the exhaust gasket from blowing out. If coolant start sipping out of that #1 stud, I will be crying. But I guess my solution will be what alkemyst mentioned above, use RTV to seal it.

I just keep my fingercrossed and hope everything is fine.

[alkemyst]

when you say you used 1/4 length of the helicoil, why did you do that? You should have been able to use it all, and sort of need too to get it to work right. Being you had the engine out it would have been better to set up under a drill press and go in exactly the depth of stud end.

I am wondering if from the factory the stud gets exposed to coolant...this front stud seems to break for a lot of people and I haven't heard any stories of any others breaking.

[gunluvS14]

i measure it up to the thread length of the replacement stud, I can't use up the whole helicoil. Maybe I exaggerated a little, but I didn't use anywhere close to half of the free height helicoil.

I'm not really worry about it, the stud is tight and straight, I should have a good seal.

[Ceepo]

Go read my post, i had a stud break 2 days ago and there where alot of good ideas to get it out :) i just need to try them...

http://zilvia.net/f/tech-talk/235635-exhaust-stud.html