Copper flanged exhaust nuts, DO NOT USE THEM Options

[VaccaRabite]

I have never pulled an exhaust stud before while doing pipes. This evening I’m 4 for 4. These copper flanged nuts locked on the studs and there was 100% no getting them off without the studs coming with them.

Going back to using just regular nuts with 12mm flats. So much for trying to get the “right” part.

Edit to add details:
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The nuts in question are commonly available and sold as exhaust nuts. I got mine from Auto Atlanta - but many places sell them. The have a copper color to them and the bore is slightly oval. The are designed to lock on to the stud - which I did not know at the time. They go on tight and you can not remove them without pulling the stud.

There are flanged nuts that work fine.

Kinda furious with myself right now.

Continuing to live life as an object lesson for others…

Zach

[ClayPerrine]

Years ago I had to have a head welded up the night before the MUSR so we could make the event. The car was running great, but on the way home from work, it spit an exhaust stud. The hole had been drilled and a step stud installed. This left the wall between the stud hole and the combustion chamber too thin. So it blew a hole from the combustion chamber to the hole for the stud.

I got home and immediately dropped the engine and pulled the head. I was pissed and in fix it mode. I took a still warm cylinder head to the local VW machinist (Lyle Cherry.. RIP) and he welded it up and re-machined it that evening. I took it back to the house and reassembled it. The next day we drove it to the event, and didn't have a single problem with the car the whole weekend.


I don't really like stepped studs or helicoil/timecert fixes. I feel there isn't enough meat on the heads to put them in safely.

These days, a set of new heads is the way to go. The current ones are 50+ years old and very questionable about what has been done to them over the years.

[930cabman]

Years ago I had to have a head welded up the night before the MUSR so we could make the event. The car was running great, but on the way home from work, it spit an exhaust stud. The hole had been drilled and a step stud installed. This left the wall between the stud hole and the combustion chamber too thin. So it blew a hole from the combustion chamber to the hole for the stud.

I got home and immediately dropped the engine and pulled the head. I was pissed and in fix it mode. I took a still warm cylinder head to the local VW machinist (Lyle Cherry.. RIP) and he welded it up and re-machined it that evening. I took it back to the house and reassembled it. The next day we drove it to the event, and didn't have a single problem with the car the whole weekend.


I don't really like stepped studs or helicoil/timecert fixes. I feel there isn't enough meat on the heads to put them in safely.

These days, a set of new heads is the way to go. The current ones are 50+ years old and very questionable about what has been done to them over the years.

Is metal fatigue the question with 50+ years old aluminum?

[ClayPerrine]

Years ago I had to have a head welded up the night before the MUSR so we could make the event. The car was running great, but on the way home from work, it spit an exhaust stud. The hole had been drilled and a step stud installed. This left the wall between the stud hole and the combustion chamber too thin. So it blew a hole from the combustion chamber to the hole for the stud.

I got home and immediately dropped the engine and pulled the head. I was pissed and in fix it mode. I took a still warm cylinder head to the local VW machinist (Lyle Cherry.. RIP) and he welded it up and re-machined it that evening. I took it back to the house and reassembled it. The next day we drove it to the event, and didn't have a single problem with the car the whole weekend.


I don't really like stepped studs or helicoil/timecert fixes. I feel there isn't enough meat on the heads to put them in safely.

These days, a set of new heads is the way to go. The current ones are 50+ years old and very questionable about what has been done to them over the years.

Is metal fatigue the question with 50+ years old aluminum?

I don't know about metal fatigue, but repeated welding of the heads can result in aluminum porosity.

A rather long winded explanation on Aluminum Porosity

And with our beloved little cars either approaching 50 years old or past it, it is safe to assume that the heads have more than likely been reworked in the past. And in the 1980s, they didn't have the technology to weld aluminum like they do now. It is possible some DAPO took a gas torch and a long stick of aluminum and welded them up in the past. We have absolutely no way to know 40 years later.

With the cost of new heads being almost the same as it takes to repair an old one, I will be buying replacements in the future for all of my build needs.