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wbgoggans
To make a long story short... I had a bad exhaust leak. Bought new exhaust gaskets. Bought new exhaust studs to replace the exhaust bolts. When I tried to put one of the m8 exhaust studs into the one spot that had no exhaust bolt/ stud I found it to be much larger( damn you PO). I then went to the local parts store and bought the largest exhaust stud they had in stock ( m10). Even this is too small, so I’m estimating the po drilled it out to about an m12. Where can I even find an m12 exhaust stud? Am I going to have to have to settle for a bolt? Worst case scenario what are the odds I can get a good seal with just 7 exhaust studs? When will my project ever be done? What is the meaning of life? Should I just go ahead and buy a flat 6? I need answers!!!!
Superhawk996
No you are not going to get a good seal on only 1 bolt for the exhaust pipe that has a hogged out stud.

Check the head carefully. The stud was probably previously drilled for a Timesert, Case-saver, or Helicoil.

Since you reference a M12 size hole (almost 1/2") that seems like it is far more likely to be some sort of Timesert or Casesaver. Are you sure it is even tapped metric? DAPO may have tapped SAE. Just sayin'

I'd be surprised if you can get a M12 bolt though the exhaust pipe flanges or if the head has enough meat in the stud area for a M12.

Proper fix is to remove the head, weld up the hole and re-tap.

Alternately, if you can figure out what the head actually is tapped for, you can have a machine shop turn up a special stud. Say M12 on the threaded end into the head, and then M8 on the end that will go though the flange.

I'd guess the right shop machine shop might do it for about $80 for a custom stud. Or find a friend with a lathe and provide the beer! No more than about 1/2 hr of work. Likewise, a machist could do a SAE on the head side (if . . .that is what it is) and M8 on the flange side so you don't have to mix and match nuts.

Would be cheaper than head removal and welding and would be a reliable fix.

If you can't afford either of those fixes you definately shouldn't contemplate a six. laugh.gif

Can't help you on the meaning of life - I've too have been stuggling with that one lately, given how crazy the world has gone.
Superhawk996
And if you haven't seen this thread yet, it pertains to your situation.

http://www.914world.com/bbs2/index.php?showtopic=353319
IronHillRestorations
I know some 1.8's use a stepped exhaust stud, which might make you think it had been drilled and tapped to larger size
bdstone914
QUOTE(wbgoggans @ May 10 2021, 08:26 PM) *

To make a long story short... I had a bad exhaust leak. Bought new exhaust gaskets. Bought new exhaust studs to replace the exhaust bolts. When I tried to put one of the m8 exhaust studs into the one spot that had no exhaust bolt/ stud I found it to be much larger( damn you PO). I then went to the local parts store and bought the largest exhaust stud they had in stock ( m10). Even this is too small, so I’m estimating the po drilled it out to about an m12. Where can I even find an m12 exhaust stud? Am I going to have to have to settle for a bolt? Worst case scenario what are the odds I can get a good seal with just 7 exhaust studs? When will my project ever be done? What is the meaning of life? Should I just go ahead and buy a flat 6? I need answers!!!!



Not stud larger than 8mm will fit thru the hole in the heat exchanger. That is why they make a step stud that is 9mm on one end and 8mm on the other. Most time certs are 1/2-13 thread.
Installing one with the engine in the car is tricky. See if a 1/2-13 bolt will screw into the hole.
I made cut off heat exchanger flanges to use as drill guides for step studs and time certs. You can borrow them if needed. Hopefully you can install a time cert abd a fresh standard stud and be done.
You are on your own to figure out the meaning of life.
Good luck
wbgoggans
QUOTE(IronHillRestorations @ May 11 2021, 08:16 AM) *

I know some 1.8's use a stepped exhaust stud, which might make you think it had been drilled and tapped to larger size

I don’t think so. All the other studs went in no problem
wbgoggans
I think I’m going to try a helicoil and see if it will fit
wbgoggans
Well actually I will try the 1/2-13 bolt. If it’s not threaded for time-sert I will go with a helicoil
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