Tap broken off in exhaust manifold head stud hole...

[4gfun]

....and unfortunately it is the stud that is connected to the oil system!

Long story but I needed to retap the below hole. I tapped it and when I finished, I went to back the tap out and heard CRACK.

I have tried to use a center punch and then an easy out, but can't make a dent in the broken tap.

I am worried that if I drill it out, I will get tons of filings in the motor.

Do I need to pull the head, or is there another way around it?

Thanks

 

[99gst_racer]

Man, 12mm seems huge. You'd have to greatly enlarge the hole on the manifold. Then is the 12mm nut going to spin on and clear the rest of the manifold casting? If it were me, I'd do what Bryan mentioned and weld it shut and re-tap. Option #2 would be some sort of insert that allows for a smaller stud. Either way, I don't think 12mm is a good idea.

 

[4gfun]

Man, 12mm seems huge. You'd have to greatly enlarge the hole on the manifold. Then is the 12mm nut going to spin on and clear the rest of the manifold casting? If it were me, I'd do what Bryan mentioned and weld it shut and re-tap. Option #2 would be some sort of insert that allows for a smaller stud. Either way, I don't think 12mm is a good idea.

Well, 10mm fits right through the gasket (at least the 4 layer one it does). You have a point on the 12mm. I will try it out tomorrow. Possible Bummer...

Just checked it out....there is enough room back there for a 64mm nut ...so I am fine. Just put the 12mm up to the 2g manifold hole and gasket. It is so close that you can almost turn it through the gasket literally. I won't do that but you get the point.

I think this will be work. The only thing that concerns me (as previously mentioned) is the strength of the casting. Option 2 still sounds reasonable, but don't know if there is anything that would convert it from 12mm to 8mm. I also think that I'd be better off with just one straight bolt, rather than 2 opportunities to leak oil/pressure etc.

A little good news for the hassle...found out that there are ARP head studs in there. A little nice surprise for pulling the valve cover.

Got it all together. I used an 8.8 12M 1.75 bolt in there with a lock washer. Is it ok for the bolt to protrude into the head? Would that hurt flow or anything?

Is the bolt itself ok to use?

Thanks

 

[danielkile]

get a screw extractor kit, it comes with bits that are real small and wont make too much mess... I had a stud snap off and thats what i used and it worked great