Exhaust head studs

[namwv]

Is there an easy way to get them out. Mine are really thin at heads.

[TimGud]

You could weld a nut onto them, squirt with pb blaster, and back them out.

[Mr. Bubblehead]

I've got them out before by heating up the stud area with a propane torch and using vise grip pliers. This is also a good way to break them off, though, then you'll need to drill them out, tap the stud hole, and insert a helicoil.
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[Phillip3560]

Ok, got a problem that I need help with. I was installing a new muffler on my 1971 VW bus and got 3 of the 4 nuts tightened just fine. I put the nut on the 4th head stud and before I knew it, the stud had backed out of the head! I don't know if I can just put the stud back in and try to tighten, tap the hole in the head and put an oversize stud in or what? I have attached a few photos for reference.

Any suggestions on how I should reinstall the stud would be greatly appreciated. I am almost at the end of this restoration project and now I have a head stud that has come out.

[Wildthings]

You might be able to get by with a stepped stud. 9 or 10mm on one end and 8mm on the other. Various inserts would work as well.

[SGKent]

thread cert or heli-coil it. You'll have to take the exhaust off and buy a kit to do it. You'll do more if you own a tired VW. It happens. If you can't get a drill 90 degrees to it you'll need to pull the motor.
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[busdaddy]

Looks like it's already out on the ground, the muffler will have to come back off, then drill and re tap for a step stud, or look into Helicoil or another thread repair. The step stud is the easiest.
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[Danwvw]

Yes those ideas work however since the engine is out why not rebuild it and use new heads and maybe do something about that orange paint.
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[SGKent]

speaking of orange paint. Unless the last exhaust was a header that wasn't drilled out. You might want to make sure that tube is open and not blocked. The paint should be discolored from the heat near the muffler.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Phillip3560]

Thanks for the input. Since there seems to be aluminum on only three of the stud threads, any chance that cleaning out the hole with a 8mm tap and reinstalling a new stud would work----Or is that just wishful thinking? I've never installed heli-coils so I may try the step stud approach.

Wouldn't you know that this was the last nut to be tightened before putting the engine back in!!
Orange/red paint was due to my father who was the PO. For some reason he always thought red paint and black engine tin looked good for some reason.

[SGKent]

[Phillip3560]

If I were to go the step stud route and can find a 9mm x 8mm stud, do you think I could tap the hole without drilling a pilot hole since I am only removing 1mm of material? I would think I would need to drill a pilot hole if I could only find a 10mm x 8mm step stud since I'm not sure a tap could removed 2mm of material without breaking-----and then I would really have a problem if that occurred.

[Our79Westy]

I found success with this step stud during my rebuild.

i also used a torque wrench and copper crush nuts.

not sure if you have enough metal to tap larger so be careful and good luck.
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1979 Westfalia DELUXE 2.0 FI manual
Mexican beigeutiful and mostly original.

See the most up to date status of Constance on YouTube
https://m.youtube.com/channel/UCvO1ZedS22IepvvRYaTxiPQ

My 1979 Westfalia Campmobile's sundry Tales of Constance
http://www.thesamba.com/vw/forum/viewtopic.php?t=620965

1990 Vanagon, Red, Driven 70,000 miles till sold.

[Phillip3560]

What was the torque value that you used? I can't find a torque value for the nuts holding the muffler to the head stud. I ended up getting a helicoil kit and will see how that works out once I get some good weather.

[Our79Westy]

From the Great Green Book it looks like 16 foot pounds

Please excuse my memory but I think what i figured out was that in order to insert the helicoil I had to tap the head to the same size as the step stud anyway...and reading all the helicoil or other insert blog entries left me wanting...wanting a professional to install something like that...

There are more knowledgeable sambanistas that I'm sure will chime in to debate the pros and cons of each method...I went the easiest route for me and my situation.

Best of luck with whatever method you choose
_________________
1979 Westfalia DELUXE 2.0 FI manual
Mexican beigeutiful and mostly original.

See the most up to date status of Constance on YouTube
https://m.youtube.com/channel/UCvO1ZedS22IepvvRYaTxiPQ

My 1979 Westfalia Campmobile's sundry Tales of Constance
http://www.thesamba.com/vw/forum/viewtopic.php?t=620965

1990 Vanagon, Red, Driven 70,000 miles till sold.

[Phillip3560]

Thanks for the torque values. My bus is a 1971 model but I can't imagine the torque values being different than the chart you sent. i'll let you guys know how it turns out.

[SGKent]

one bus is a T1 engine and the other a T4. Different heads.

Type one engine

Type 4 engine. Totally different way of attaching.

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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Wildthings]

[airschooled]

I like closer to 14ft*lbs and constant re-torques after heat cycles for a few days. Prevents things like this from happening in the future.

If you try to clean up the existing threads for M8, use a thread-chaser first, not a tap. Thread-chasers have less aggressive construction, and are designed to realign beat-up threads instead of cutting into new metal, like a tap. I almost always have to chase spark plug threads in my high-milage T1 heads; the aluminum seems to like it. (Plus, it would have saved me a Time-Sert in 2016.)

Take the muffler off and chase it totally straight. I use red thread-locker though I don't think it's necessary. Bottom out the stud gently, then loosen it quarter to half a turn. Let the thread-locker dry and coat the exposed threads in anti-sieze before installation.

Torque to 12-14 ft*lbs, then do it again the next day. You WILL find some of them need it. Repeat until none move any more, then paint every millimeter of exposed threads and nuts with hi-heat paint, and you'll never fight them coming off.

I really do think VW used a too-high torque value in this application, so cars wouldn't have to come back to the dealership for re-torques to prevent leaks. This is YOUR car and YOU are in charge, so you get to choose how it goes together. (Plus, you get to ensure that the stud threads deep enough to prevent this from happening again…)

Are you familiar with the Double Nut method of installing studs?

Robbie

PS- once you've cut your teeth on these, you get to face the final boss:

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[SGKent]

Robbie - wait until you break an easy out in something NLA.
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