Drilling/tapping for larger exhaust studs Options

[ChrisReale]

I have two exhaust studs that need to be replaced. I have two 10mmx8mm studs that I want to use. What size drill bit do I need? I take it something slightly less than 1mm? Any "been there, done that" experiences one would like to share regarding this subject?

[nebreitling]

i'll procrastinate a bit and respond...

1) the M10 tap package will probably have the reccomended drill bit size. smaller is safer at first.
2) wear safety goggles
3) drill straight, tap straight.
4) go slow, back it out every few turns to let out the shavings
5) seriously, tap straight
6) avoid crooked studs by making sure you tap straight!


as you may have suspected, i didn't tap straight. crooked stud. not fun.

it's easy, though. just don't screw up.

[ChrisReale]

2) wear safety goggles

.

dont rub it in... <_<

[nebreitling]

wear a hat or something too. i had aluminum shavings in my hair for a day or two after i did mine.. GF was not impressed.

[nebreitling]

oh yeah, maybe use a little cutting lube

[Brad Roberts]

Helicoil or timecert. The oversized studs are cool... but unless the head is seriously dorked..


B

[McMark]

wear a hat or something too. i had aluminum shavings in my hair for a day or two after i did mine.. GF was not impressed.

Or you can take a shower more than once a week. (IMG:style_emoticons/default/wink.gif)

[J P Stein]

Go to a good hardware store. Run a nut that fits onto the engine side of the stud......that'll give you the thread pitch & size....make a note of that.
Now, stroll over to where they have taps & drill bits. Find the tap size you need. The tap package normaly has the required drill bit size listed on it.....get a tap handle while you're at it.
Prolly 25 bucks total.

True Value usually has the stuff you need.
Are the old studs broken off in the hole?

[Joe Ricard]

I just did the fix for one exhaust stud. used a 8mm helicoil. came in a pac 10 helicoils (threaded inserts) and a tap and insertion tool. bought a good drill bit that was not included. I got a cobalt one. Size was on the package.

DRILLED and TAPPED it STRAIGHT and went SLOW. little bit of JB weld to make sure the thing didn't EVER come out. so far it is working.

[ClayPerrine]

PLEASE NOTE!!! Due to some recent experience, I want to chime in on this. DO NOT DRILL OR TAP ANY DEEPER THAN THE ORIGINAL HOLE!!! I did, and the monday before the MUSR, I was on my way home and I started having an exhaust leak. Took it home and found that the exhasust stud had pulled out, and taken the top of the combustion chamber with it! Basically "Oh SHIT!!! I have a hole that goes straight into the top of the combustion chamber!!!"

I pulled the engine and the head in 2 hours. Took it to Lyle Cherry's shop, and luckly he was there. He reworked the head (found a rocker that wasn't oiling causing bad valve guide wear) and gave it back to me Tuesday night about 9 pm. Put the car back together Wed during the day, and fired it a 5PM. Drove to Oklahoma for the MUSR the next day without a hitch.

When I asked Lyle about redrilling and tapping the exhaust studs, he recommended that if they pull, take the head and have it rewelded. Don't fool with "half-assed" fixes. He said, if you have to use an insert, only go to 9mm, and only use a heli-coil. Time-certs require you to remove more meat from the head, and that can lead to failure of the head like I saw. FYI- Lyle Cherry has been racing VWs since the early 60s, and knows these engines intimately.


Point is, don't overdo it with the depth. It can bite you in the ASS!

[Mark Henry]

Helicoil is how I would do it, then use a std. 8mm stud.

If you do use an oversize stud try the 9mm first. By the time you go 10mm you don't have much meat left and if it pulls out you will have to get the head welded.

[skline]

Helicoil is how I would do it, then use a std. 8mm stud.

If you do use an oversize stud try the 9mm first. By the time you go 10mm you don't have much meat left and if it pulls out you will have to get the head welded.

(IMG:style_emoticons/default/agree.gif) I have both kits here I bought when I had my yellow car. I used them once each on different studs. I think they were like $20.00 for each kit and you could do 10 studs with each kit. If anyone needs them, send me a PM and we can work something out.

[skline]

Actually, I just looked at the kits, one is for the M8 and the other is the 10. The 8 kit has six left and the 10 has 9. So I either lost a few of the 8's or used it on other cars. The kits are still complete with everything you need except the studs which you can get at any VW parts house. I gave my extra studs to Joe Buckle I think, or maybe it was DrifterJay. Anyway, they are cheap and readily available.