BD: Exhaust Stud Size / thread size?

[d1giPhux]

I might be replacing my exhaust studs soon where the header attaches, and have been reading a lot about how to re-tap the holes.. etc. etc.

I'm pretty sure I'm going to be going with a 7/16 x 14" thread as that allows for a quick fix, and also does not increase the size of the hole much, and will not need to be drilled out, heli-coiled..or any of that other crap. Unless it ABSOLUTELY needs to be done. This is assuming the studs are M10 x 1.25mm.. which.. i'm unsure of.

I'm wondering.. does anyone know the size of the exhaust stud?

How much threads into the engine itself?

How much thread is there sticking out that the header attaches to?

Would these studs work? :

http://www.mcmaster.com/#92386a673/=3kis2i

Or where could i pick up some 7/16 x 14 threaded rods and just make my own?

Let me know any info you may have on this. Thanks.

[rudgers73]

I broke one of my studs when I put on my header a couple of years ago. (Yes, they are M10 x 1.25 BTW) At the time I tried everything to get it out, but it broke flush and those studs are hard as balls, so I ended up digging in from the side to work it out with a punch. That added a bit of slop to the hole, but it still was fine until I had work done at the dealer and they torqued it and reamed the hole out.

I did a bunch of reading and research and decided to Helicoil it. It's good as new now.

There is about 5/8" that goes into the head, and about 3/4" sticks out IIRC.

Why do you want to change the stud size/material in the first place?

PS ***If you are going to drill it at all be very careful b/c the other end of that blind hole leads right into a water jacket. If the drill bit bites and pulls itself too deep you are going to need a new head.***

[d1giPhux]

The reason for going to 7/16 x 14 is that.. you dont need a drill to re-tap the hole. Also.. the hole is STILL smaller then the hole needed to heli-coil it.. so thats a plus! The hole is just stripped out, there is no more exhaust stud there.. hence why i want to get one in its place.

Any people have any other suggestions?

[rudgers73]

oh, I didn't know that you had a stud stripped out and missing. Yeah, you wanna do something about that ASAP because I learned the hard way that in a header with 3 studs you need all of them or you have a leak, It's like a hole in your torque... haha

You can do the larger stud, but still, I would recommend going the extra mile and doing the helicoil. That way you keep OEM parts and you don't need to remember which size you used on that particular stud, blah, blah blah. I think botching parts is the quickest way toward making your car a pain in the ass. Keep it clean man, don't cut corners, JMHO. But it's your car, so it's up to you.

Let me know if I can help you out in any way.

Good luck, and take your time.

[d1giPhux]

Cool thanks.. but yeah, I heard this is the best way to go actually. Because your not really increasing the size of the hole much.. which is great. You don't need to drill (less risk), and you don't need to heli-coil because this works perfect. If this DOES happen to fall out later.. you can still heli-coil.. which is why I would want to do it. It basically gives you 2 shots at fixing the problem before it becomes a real problem. As opposed to heli-coil / timesert inserts and such.. which only give you one chance. However.. timsert sleeve would probably be the best way to go..since even if it does strip out again you can keep threading them into each other unlike heli-coil.

Do you recommend using stainless steel studs? I heard that would probably be the best way to go.

Did you find doing this to be easy, or hard.. or in-between?

Also, what should i use on the threads going into the engine? RED Loctite, or loctite 'thread renewal' stuff... which i heard is actually VERY good as well.

[d1giPhux]

Anyone with any comments on the type of hardware i will be using to do this?

Stainless Steel Studs:

http://www.mcmaster.com/#92386a673/=3lseb8

-Are these strong enough?
-Course threads a good idea on the block metal type?
-Are they heat resistant enough?
-Are the block threads long enough?
-Are the exhaust side of the threads long enough?
-1.5" Length total long enough?

I will be using 7 / 16 x 14 .. as i think its the best size to use for this.

-Should I file the ends of the studs into squares.. so that they can be turned with vise-grips or another tool?

Anyone with suggestions on doing this.. etc? Thanks.

[d1giPhux]

I'm looking back on this thread and have a couple of questions. When i thread the new studs into the block.. ive heard i should use 'lock washers'. Where would I want to use these.. and why? I'm not even really sure what is so special about a lock washer?

Info please?

[97scoob]

you would probalby want to use a lock washer on the nut that holds the header on, the one that threads on the stud. so it should go header on first, then lockwasher, then nut. this will make it so the nut cannot vibrate and come loose.
https://sl-i.net/FORUM/images/imported/2009/10/lockwasher-1.jpg
that is a lockwasher. see how it will have like a lip on it so when the bolt tries to back out, it can't

[d1giPhux]

awesome! thanks for the pic man. I can get those from any hardware store or something I'm assuming?

[jey]

Yup, hardware store.