Installing an Izzo Pompeii piston in the group

#1: Post by **espressotime** » March 9th, 2013, 10:22 am

I cleaned up the group of my Pompeii.
As I wanted to install the piston the seal went in perfectly but the teflon ring won't.As if it is too big.
I must say the machine is still hot.So may be that's the problem.Has anybody ever been there and has a solution?
thanks

March 9th, 2013, 2:44 pm

Measured things.
The bore of the cylinder is 50 mm.
The diameter of the teflon ring is 52.5 mm.Could it be the ring is being pushed outwards by the spring pressure?

#3: Post by **peacecup** » March 9th, 2013, 3:35 pm

That looks a little odd. Is it being squeezed outward like you say? How can you relieve that pressure?

I thought you went for a Achille, not a Izzo. Have you noticed any difference from the Strega?

PC

March 9th, 2013, 3:48 pm

Since the spring is hold by a nut there's no spring pressure on the teflon ring.Looks like the only pressure is from the piston that's screwed on to the piston stem.That pressure can't be that strong it seems to me.Can't figure it out.

The Pompeii makes great espresso.Really great.

#5: Post by **JimH** » March 9th, 2013, 4:09 pm

What's the diameter of the teflon gasket when it isn't being compressed by the piston?

It might be necessary to insert the piston with the teflon gasket uncompressed, then tighten the lower section from below when it is inside the cylinder. I'm guessing that would create a nice tight seal.

March 9th, 2013, 4:34 pm

The teflon ring is one piece.So I can't compress it.It's real hard .Somehow it has grown 2.5 mm in diameter since it's been out of the cylinder.

I got the Izzo explosion drawing and the part in the drawing has a diameter ot 50.

Part GL 40 in the drawing.
Hard to see but it says Guarmizione PTFE 39.7x50x5.5

#7: Post by **bmb** » March 9th, 2013, 5:39 pm

Wild guess: if you freeze it ?

March 9th, 2013, 5:52 pm

I did put it in the fridge for 10 minutes and heated the group already.Maybe I should put the group in the freezer for a couple of hours tomorrow.
Thanks.

http://users.rcn.com/erics/ · #9: Post by **erics** » March 9th, 2013, 6:01 pm

Hey Alf Alf -

Something is amiss here and I wish I could tell you what. I would put down the tools for the weekend and give Mr. Izzo a call on Monday. That group was obviously(?) assembled under room temp conditions and you are headed into trouble as I read it.

#10: Post by **bmb** » March 9th, 2013, 9:06 pm

Eric's is the best advice, as always.
Just to clarify: I meant putting the piston with the gasket in the freezer (to shrink with the cold temperature) not the group.
I remember there were some car repairs, were parts had to be submerged in liquid nitrogen to fit.
Anyhow, you should follow Eric's advice.