You're listening to too many people.
I've had swivel-foot adjusters since day one. Only have one, normal jam nut on them and never, ever, had one go out of adjustment. Had one swivel get "cocked" once, when I had the rockers off to install adjustable push-rod tubes (more on that in a second) which, when it popped around into the right position after about 5 minutes, immediately got me to 40 thousandths clearance on that valve, but that was MY fault, not the hardware and nothing hurt. Take your time to install and adjust them properly and I think they're great.
BTW, As you know, when you adjust the valves and then tighten the locknut, you're holding the screw-slot end of the adjuster stem with a screw driver to keep it in place and not turn slightly, pushing you out of adjustment. It's MUCH harder to hold that stem in place with a screw driver if you're using something like a crimp nut or Nylok stop nut because of the resistance of the nut. THAT is why VW used a simple jam nut.
On the adjustable push rod tubes, when I pulled the engine to get the transaxle rebuilt, I found that I had 2 weeping stock VW PR tubes on one bank - the other bank was fine. Looked around the Samba and Shop Talk Forums and found that the threaded, adjustable tubes seemed to be at least OK with the technical guys, so I got a set of those from Air-cooled (I think...But it might have been CB) and had to remove the push rods to install them (You remove the rockers and pushrods, then use a pair of water-pump pliers to crimp and twist the old pushrod tube at the same time and then yank it right out - just like a molar at the dentist....without the pain). When I put everything back, I had a swivel-foot adjuster cocked to the round side, not the flat side.
So that's why I ended up with one valve banging like hell. Quick drive home and the next morning re-set it to loose zero and it's been fine ever since.
What "special nut" have you been looking for and why - - - and who recommended it?
gn
