Howdy. Snapped off an exhaust stud while replacing the heat exchangers. Going to make a drill guide that will index off the remaining stud so I drill in the center of the snapped one. But I need to know the bolt centers between the two studs. Anyone know that measurement? Thanks in advance.

The bolt patterns for the /4 engines on the exhaust studs are all the same. Find an early 1.7 heat exchanger with the cast flange and cut it off. It makes an excellent drill guide for the broken stud. Install it without the copper gasket so it aligns correctly.

Clay

Bear in mind, even with a drill guide you will probably ruin the threads and have to move up to a step stud. Not a huge issue. Also, make sure you have a drill stop on your bit, and that you really measure how deep you can go. When you tap, you will need the taper or plug tap to get started, but this is a case when you REALLY want that bottoming tap to get the last threads in your bore. Otherwise, you will not be able to seat the last 3/16th or so of your new exhaust stud.

Before you try drilling, have you tried building the stud back up with weld and welding a nut to it? The weld wont stick to aluminum, and the heat from welding will help break the crusty bond the old stud has with the head.

Zach

http://www.914world.com/bbs2/index.php?showtopic=363423

Use an old exhaust stub/flange as a guide. Bolt it to one stud and use the other hole as a guide. Replace it with a TimeSert or, if needed, a BigSert.

I've got a recalcitrant exhaust stud with my name on it. Tried to back out and got stuck when I removed the headers on the race car, and now won't go out or in, it's galled in place. I'm putting that unhappy job off for as long as possible...

If you have anything of the old stud sticking out, weld a nut on it. I use a gas torch for that. The heat helps break the stud loose from the head.

I like to use the reverse drill bits in a cabinet screw centering guide. Keep tapping the trigger on the drill as you go in and often it will catch and back out the screw. All this stuff is available on Amazon for not much money.