...I did this sealing process in the 79 the week previously to the crash and followed the 79 parts book I ordered the 2 O rings that go inside the tubes and the square one that goes around the tappet block that the wedding band hold it; so all the stuff is used in the 79 models.
Yes that's correct. I'm not sure when the alteration was made, but all 79 models I've worked on were like that. Feked list the new parts as 79 on. Maybe the change was implemented during the year, but more likely after August for the 1980 season. Healy will know. My Harris Bonneville used the later system.
Although I always thought the O-ring system seemed superior, to be honest it doesn't work any better, or worse, than any of the other systems Triumph used, in my experience.
Careful assembly with attention to detail, as described so well by Don, is paramount. Once you get it right, it will stay oil tight for years or even decades.
I've toyed with the idea of altering the PRT system by boring out the recess in the head and inserting a piece of aluminum pipe that would spigot inside a new design PRT.
This pipe would either be welded in, or flanged and pressed in, or any other way that would keep it oil tight..
At the other end one could use a piece of pipe crimped or welded on to the tappet guide block, into which the PRT would go.
One of the problems would be the PRT angle, there would need to be an amount of play in the system to allow for this. I'd use O-rings on either end. Flexible PRTs could be used too.
With this design, the need to measure PRT seal crush and the issues with that, would simply vanish.
This isn't "a brilliant new idea", it's a system used on many designs since forever on machinery, including bike engines, or on mundane things like drain pipes etc.
Shouldn't be too hard to do either, if I could find the time.