Exhaust stud - drill out with Stromski

[rip78sc]

Hey guys - have the broken exhaust stud issue, bought the Stromski tool from the host and the drill out is going great, works like a charm. My only concern is going too deep and through the head. What depth do I need to hit?

I've measured the studs and I'm guessing I need to drill down 1.25" and I've read on the board 1" - I'm currently at a depth of 5/8".

1978 3.0 SC - stock heat exchangers.

Am I close or good enough?

Thanks,
Rob

[john walker's workshop]

You'll know when you're throught the steel and into aluminum. Just stop.

[jlex]

If you strike oil, you've gone too far...

[Ian Comerford]

There’s usually a gap between the end of the stud and the bottom of the hole. You will feel the drill bit go through the end of the stud and into the gap.

[rip78sc]

well got it drilled out without going through the case! for informational purposes the depth is approx 7/8" or 22 mm.

I bought the 51mm studs from our host so I'm a lot taller than the ones in there already - going to do a test fit to make sure we're all good on clearances.

https://www.pelicanparts.com/More_Info/99906223702M260.htm?pn=999-062-237-02-M260&bt=Y&fs=0&SVSVSI=

Used some blue locktite on the threads and left about 1/16" before bottoming out for expansion. One question, I installed the shorter end of the threads into the case as when I measured against my heat exchanger the other way would have the non-thread piece above the exchanger so I could not tighten without some type of spacer. I assume this is correct?

[rip78sc]

Here is a pic

[john walker's workshop]

Why longer studs than original? The allen nuts won't work if the studs are too long unless there's a stack of washers or a spacer tube under them.

[rip78sc]

I didn't have one to check the length of the original and the 51mm is what shows for my year - I assume there are shorter ones huh? Any idea what length I should be using? should be easy enough to swap out.

[john walker's workshop]

A '78 would have thin flange exchangers, so definitely short ones. Same as a 73 for instance, so look that one up. Don't remember right off.