Hi everyone,
have been reading the forums for some months now and bought this chrome Riviera without the dome.

I've read here that you can use Elektra seals for the Pontevecchio Export/Riviera 3 seal piston.
So one of my nearest parts sellers had them, one U and one W, and I got them. They have a larger ID, 28 mm vs 24 mm of the recommended Pontevecchio G8094 seals. So I've added some PTFE tape for some thickness, now they don't spin freely.

Trying to fit them inside the group without inserting the spring yet:

Also added a thin layer of silicone grease on the seals.
It looks like the U-seal works OK, but the W-seal is a bit on the fat side(?).
Has anyone else tried these on the 3 seal Riviera piston?

And one more thing: Elektra MCAL users, what's the inner diameter of your group? Meaning the chamber where the piston travels.

Thanks!
BR
Konstantin

An update to the story.
So I've fabricated this tool after seeing the Insta page of @max.macchina.a.leva:


It allows me to lift the piston in the smallest increments and to make adjustments to the seals.

The Elektra seals work with silicone grease, the piston travels back and forth.

However I've added a 45 mm by 20 mm inner spring inside the main Zacconi spring and the piston pops out of the group downwards a bit in the "resting" position. Added it because the original spring is obviously "tired".
I've tried to shorten the inner spring so that it doesn't push on the piston in the uncompressed state, but it doesn't help.



I'm sure that the piston didn't pop out when I first disassembled the group in March or April.
Could it be because I've left the Zacconi spring unattended in the box without compression for several weeks? Could it have gained a couple millimeters while completely uncompressed?

The three seal Riviera piston should be compatible with Ponte Vecchio piston seals. You install two V seals back to back and one more in the other groove. They should fit without any tape

Riviera had both two seal and three seal models of the spring group piston. The three seal models are Sama/PV pistons. The two seal model is more rare and it more or less matches the DeCarli La Romana. MCal seals will work for it.

Also, La Macchina del Caffe may have the Riviera spring. Otherwise, use a PV spring. It should solve your problem. The original Riviera spring was relatively low tension, btw. Yours may not be as tired as it seems.

I know the PV seals, but I can't buy them right now (the same for the PV spring). Yet the Elektra seals are available and the above mentioned thread states that they can be used even despite the different IDs. So this is me researching and troubleshooting this alternative

Unless I'm missing something, the springs should have nothing to do with the travel of the piston, only with the pressure exerted during its travel. If the piston is traveling too far, then most likely, the distance between the hole at the top of the rod and the bottom of the piston has changed. Does the rod screw into the piston and is it not screwed in far enough?

Actually I've just looked at my machine parts and I've noticed the lever fork was missing a thick roller. There it was in my box, completely forgotten.

And I can see that this actually pulls the piston rod into its topmost position, it becomes flush with the group!
I'll continue posting further results.
Thanks to everyone so far!