Paolo wrote:I have installed a 1/8" teflon gasket that I cut from a sheet. I am curious as to how your 37 year old Cremina behaves with the Olympia gasket compared to how it was without. Personally I can't think of a single reason to remove it. It makes my 1987 Cremina so much more useable over multiple shots.

Having tried my Cremina 67 with the OE O'ring & the factory teflon gasket I prefer the teflon gasket. That said it still takes quite a while for the group temp to drop back down by itself after the first shot to the point where you can pull a second shot. I usually run cold water over the p/f & lock it back in a couple times to pull the group temp back down to an acceptable shot temp (185*F-187*F external measurement).

I'm about to do complete rebuilds on 2 Creminas. Ordered 2 OE complete rebuild kits and then realized I still had a OEM group/piston kit. So I'm thinking of using one of the OEM piston gaskets on each for the lower gasket and an OE for the upper.

The OE seals feel better. If your machine isn't one that experiences the problem there may be no need to run the OEM seal on the bottom groove.

The test is to remove the shower screen and leave it off - let the boiler get up to pressure and slowly lift the lever and hold it at the spot where the first bit of water starts to enter the chamber. It is under pressure (whatever pressure your P-Stat is set for - maybe .9 bars). If you see a high pressure, focused stream of water shooting straight down out of the group into your drip tray - that is the issue. If you see water dribbling down from all over the place just falling from gravity rather than a blast at high speed then you don't have the issue.

If you raise the lever any further - there will be a lot of water rushing in (very hot - be careful) and bouncing all around. The idea, though, is that you should be able to hold the lever for a second or two where it barely opens and get a gradual preinfusion to wet the puck (ideally without the jet blasting a hole in the puck) before you raise the lever further and get the fast moving rush of water to fill the chamber.

There seems to be a bit of a consensus that the Olympia seals are a bit better. Let me dispel the myth, at least for my machine. Today I thought to lower the pressure drastically since I brew espresso 99% of the time, thinking that it would help the shooting. At .2 bar, this is what happened http://www.youtube.com/watch?v=ea0a1SKe ... e=youtu.be It was worse at .5 bar, and less noticeable at .7 and up, but certainly present, as I've reported before. Here is my piston with the same seals as in the video, just to double check, sitting next to the orphan seals (OE) where the skirt comes down further and should be worse if this theory is good (for my machine). What gives?