fixing exhaust housing bolt hole.
 

So I got my turbo back from blasst and I was running a tap through some of the bolt holes to clean them up a bit. Well, naturally the tap broke off into one of the holes. I bought a cobalt drill bit to drill it out, and after about an hour of smokey-ass drilling, I got the majority of the tap out. The only problem is that now the hole is oblong and the drill walked out to the outside of the bolt hole, making the wall of the hole fairly thin. My question is, can I fill the hole with weld and re-drill/re-tap it? I know alot of you wouldn't recommend welding cast, but I will be removing a majority of the material anyway, and it is one of the holes at the bottom of the flange, where it is in compression rather than tension. Oh yeah, I have a Lincoln Sp-135 with gas. Has anyone ever done this?
Thanks,
~Graham

Re: fixing exhaust housing bolt hole.
 

weld a v-band on that bitch. If you have a drill press, do it your way but dont use a handheld drill. Set the speed real low and get that fucker straight to avoid this problem happening again

Re: fixing exhaust housing bolt hole.
 

Werd, this has been a total nightmare. I'm thinking that The weld area will be very small so it shouldn't be a big deal.

Re: fixing exhaust housing bolt hole.
 

Why don't you just look for a new compressor housing?

Re: fixing exhaust housing bolt hole.
 

I'm impatient, and I didn't see any on ebay.

Re: fixing exhaust housing bolt hole.
 

Compressor housing? I have an AiResearch .42 and a T-Bird .60 if either is what you need.


JP

Re: fixing exhaust housing bolt hole.
 

why dont you just weld a stud into it or somthing

Re: fixing exhaust housing bolt hole.
 

No, its a turbine housing, I didn't even catch that when it was posted, but thanks anyways!

This was the other possibility, I even have a stud with the proper M8x1.25 threads. I just thought it may be easier to cut a new hole/threads. In fact, part of the original threads are still there, I could probably thread it in partially, then weld it.

Re: fixing exhaust housing bolt hole.
 

You should have used a tap extractor. Were you backing the tap off as you were taping it, or were you just making a straight cut with it? That is a big mistake a lot of people make taping holes, you need to back the tap off to break the chip in the hole.

And I imagine you used a HSS drill bit, which is now probably toast. lol

How far off is the hole from it's original position? Take a picture that would be great, for us giving you advice on something like this.

Re: fixing exhaust housing bolt hole.
 

My brother broke the tap off, not me, so im not sure what he did. Yeah, 2 drill bits are toast now, but I got the majority of the tap out and I welded a stud in there. Seems to hold fine. thanks for all the help!