Slide and slide, the orings have grooves that they sit in. Installing cyl 1, 3, 4 and 6 is pretty easy, you can install them delicately and precisely on a bench and get it just right. The center ones (2 and 5) needs to go in while installing the cylinders on the bottom end. It's a bit tight for space and it's tempting to twist the liner to get it perfectly aligned and in place. And that's when you might have a problem. The manual says about the o-rings: "Replace on principle, mount with special grease, do not twist". Also, the center liners could almost be pushed out by hand, the other four were pressed in pretty tight. The bottom rings on 2 and 5 were in bad shape, parts of it could be scraped off with a finger. It leaked at just 1 psi of pressure. My engine guy leans more towards bad install than heads lifting. Probably reused old o-rings. Studs measured out fine.

 

How many Porsche motors have you built?

I learned never to say never a long time ago. And from what I've read, you are older than I am.

Seriously, c'mon now!

 

Opening it shouldn't be an issue, Porsche requires a lot of stuff to be replaced, studs isn't one of them.