Replacing the gaskets in the piston of Olympia Cremina

[jmovson]

Is there a particular manufacturer that you would recommend for replacement gaskets for the piston?
Is there somewhere on this site that provides information about how to do this job?
Thanks
JM

[TUS172]

You can get the grouphead set from this site...http://www.orphanespresso.com/ind...e=index&cPath=6_28
I have not personally dealt with these people but I am sure that others here have.

How to do the Job? Do a search of this site and you will find many rebuilds that have been done and very clear directions.

[bobcraige]

For machine parts the advice I give is the same I use for old cars. If you want it to perform to factory spec, then use factory parts whenever you can...especially on critical components. The factory gasket kit is very good and meet all tolerances and specifications that the original engineers intended. I have seen many and have used a few work-arounds, but they are always temporary fixes. With the temps and pressures that these machines deal with give yourself some peace of mind and use the right parts. And as always if you are not confident with the work you are doing on a machine, then take it to a pro...

You can get the grouphead set from this site...http://www.orphanespresso.com/ind...e=index&cPath=6_28
I have not personally dealt with these people but I am sure that others here have.

From the Orphan Espresso Site:

For this reason, we designed the seal with a bit more overload than the OEM specifications call for resulting in an excellent fit. We have been using the prototypes of these seals in our Olympia Cremina 67 for a couple of months, and offer the following observations regarding their function in our machine:

The fit is fairly tight - when the lever is all the way down we have to put a finger on the front of the drip tray to start the lever movement. One may stop the lever movement at any time and the lever remains stationary at that point.

For those of us who actually know about the Cremina, having to hold down the machine while lifting the lever is an indication we need to service the machine. It is truly amazing that this vendor claims this to be a design innovation.

[caeffe]

For those of us who actually know about the Cremina, having to hold down the machine while lifting the lever is an indication we need to service the machine. It is truly amazing that this vendor claims this to be a design innovation.

I'm not sure the vendor is making a design innovation claim here - in fact the vendor claims it as an observation.
I read it as an assertion that the gasket fits tightly to the point that one has to hold the machine in order to lift the lever and that the lever will stay at whatever position one leaves it in. One may take this to mean as an improvement, one may not. I take as it is not the original mfg's intent - whether it is an improvement or innovation is subject to one's interpretation. I don't have a Cremina (i'm one of those who thinks they need one ) but have a europiccola and I can understand what is described here.

BTW, I'm not trying to defend (or offend) - i'll leave that up to orphanesspresso. Of course, orphanesspresso can chime in and tell us as I do believe they are a home-barista member.

[johhnyguitar]

First, let me say thank you Caesar for your even handed observations, we too have a Europiccola, with OEM La Pavoni Seals, and find that the 'feel' of the lever in movement is completely different than that of the Olympia Cremina. One cannot stop & hold the EP lever at any point - it has a tendency to drop down all the way, or, once past the infusion point, it will go up all the way.

On the OC, we feel that the solid feeling of control, at all points of the lever movement is a good thing, and we consider it a positive aspect of the OC versus the EP. Of course, that is subjective! We decided to spec out, have the seals made, and offer seals to fit the Olympia Cremina because of our personal difficulty in obtaining parts from Olympia Express. Numerous unanswered emails, over a long period of time, calls to Switzerland, etc., is extreme in the internet age (particularly when they have a website and email!).

We needed the parts - we had a machine, with NO seals! Before we had seals made, we ordered 2 different sets of seals for the OC, both sets arrived quickly, but neither was an OC set. Both were La Pavoni seals repackaged, with a correct group to boiler o-ring, and a portafilter gasket that was approximately, but not exactly correct, thrown in. Neither set fit correctly. Neither set was disclosed as a La Pavoni "make do" set. So we had the sets made.

The whole of the explanation (only an excerpt was provided above):

Many of our fellow Olympia Cremina owners have experienced the frustrating difficulties of acquiring the parts for rebuilding their machines. As noted in our "OC v LP Interchange Chart" the La Pavoni piston seals can be stretched onto an OC, but the overall fit is unsatisfactory to us. Fit means it should FIT PROPERLY! The height of the piston race of the OC is greater than on the LP, and even with an improvised spacer it just wasn't quite right, especially in light of the fact that the Olympia builds their machines to such exacting specifications. After much trial & error, we found a seal that fit correctly, but, because we wanted to offer the seal in Viton, we were presented with certain difficulties. Viton Rubber has a high temperature range of up to 400 degrees F, eliminating the concern of baking of the piston seal & causing premature failure. Viton has exceptional resistance to Oil, and Chemicals, as well as heat, and these seals are NSF approved. Viton has a durometer hardness rating of 75, about the same as Buna-N or high density EPDM rubber, but when working with the material we found it has greater flexibility & stretch, even with similar hardness. For this reason, we designed the seal with a bit more overload than the OEM specifications call for resulting in an excellent fit.

We have been using the prototypes of these seals in our Olympia Cremina 67 for a couple of months, and offer the following observations regarding their function in our machine:

The fit is fairly tight - when the lever is all the way down we have to put a finger on the front of the drip tray to start the lever movement. One may stop the lever movement at any time and the lever remains stationary at that point. When just passing the water inlet port in the cylinder we observe a high degree of control over preinfusion allowing a very slow entry of water into the cylinder. The fit of the seals gives a very solid & smooth feel to the lever with no looseness or sloppiness to the movement on either the upward, or the downward stroke....

There is a bit more on that page - about the installation of the seals, which I omitted from this post.

We have now been using the seals for more than 6 months, smooth as butter.

I would point out that it is subjective, again, "a finger" isn't what we would consider "having to hold down" the machine in any forceful way whatsoever. Olympia Express uses EPDM, not Viton. If you have worked with these materials, you will know that Viton has different characteristics in practice, than EPDM. They are different materials. We did not, and do not, claim that the seals are OEM seals. THAT is why we have closeup photographs of the seals, and have given a transparent, full disclosure of the materials used.

We could have, of course, skipped the full disclosure, and the technical observations, and just sold a rebuild set to fit the OC, but we respect our fellow OC owners, as well as anyone interested in coffee, and espresso in general, and prefer to treat them as we would prefer to be treated. From our personal experience, one may use an o-ring seal, made of Buna N, EPDM, Viton - when you have a surface to surface, non moving seal, but the piston is a different matter. We are very particular on performance issues - we want the seal to work today, tomorrow, and for a very long time in the future!

And, we do think our Viton Seal is better than the Olympia Express OEM EPDM seal. And, that is why we offer the seal in Viton - we could have had it made exactly the same as Olympia Express offers - exactly duplicated, but we do not. We currently offer rebuild seals for 13 different models of vintage home lever machines, and we have a few more in process - only one of them is OEM (La Pavoni has good support for the Europiccola) Keeping these machines alive is our passion, and we own at least one of each of the machines for every seal kit we offer.

But of course, we don't make anyone buy our seals! You are free to purchase seals for your machine anywhere you can find them!

[bobcraige]

I would point out that it is subjective, again, "a finger" isn't what we would consider "having to hold down" the machine in any forceful way whatsoever.

Oh, I understood that you said you had to hold the machine down with a finger-sorry for my confusion. If you have to hold it down, there is something seriously wrong with the fit!

Olympia Express uses EPDM, not Viton. If you have worked with these materials, you will know that Viton has different characteristics in practice, than EPDM. They are different materials. We did not, and do not, claim that the seals are OEM seals. THAT is why we have closeup photographs of the seals, and have given a transparent, full disclosure of the materials used.

We could have, of course, skipped the full disclosure, and the technical observations, and just sold a rebuild set to fit the OC, but we respect our fellow OC owners, as well as anyone interested in coffee, and espresso in general, and prefer to treat them as we would prefer to be treated. From our personal experience, one may use an o-ring seal, made of Buna N, EPDM, Viton - when you have a surface to surface, non moving seal, but the piston is a different matter. We are very particular on performance issues - we want the seal to work today, tomorrow, and for a very long time in the future!

And, we do think our Viton Seal is better than the Olympia Express OEM EPDM seal. And, that is why we offer the seal in Viton - we could have had it made exactly the same as Olympia Express offers - exactly duplicated, but we do not. We currently offer rebuild seals for 13 different models of vintage home lever machines, and we have a few more in process - only one of them is OEM (La Pavoni has good support for the Europiccola) Keeping these machines alive is our passion, and we own at least one of each of the machines for every seal kit we offer.

But of course, we don't make anyone buy our seals! You are free to purchase seals for your machine anywhere you can find them!

While you are doing full disclosure, you should point out that Viton is NOT RECOMMENDED for steam or hot water! Here, for example, is a typical seal material selection chart:

[johhnyguitar]

You really should let Olympia Express know that, since they specify & use Viton for their Steam Valve O-rings! Probably should let Dupont know that the Viton they've developed specifically for water & steam applications isn't working either....

[TUS172]

After much trial & error, we found a seal that fit correctly, but, because we wanted to offer the seal in Viton, we were presented with certain difficulties. Viton Rubber has a high temperature range of up to 400 degrees F, eliminating the concern of baking of the piston seal & causing premature failure. Viton has exceptional resistance to Oil, and Chemicals, as well as heat, and these seals are NSF approved. Viton has a durometer hardness rating of 75, about the same as Buna-N or high density EPDM rubber, but when working with the material we found it has greater flexibility & stretch, even with similar hardness.

It must be that Mendrisio is so close to the border of Italy that the Pope comes up from Rome and personally blesses the seals at Olympia to make them better than anything else on the planet. It doesn't matter whether the seals you buy are made of better material and correct fit; if Olympia buys (sources it; you know they don't make it) it has got to be the best on earth.
Here is a person who is very resourceful and has found a viable replacement for Olympia's seals. I congratulate you on your DD and resourcefulness.

[GB]

The numerous pages on this forum about making espresso attest to the saying "the devil is in the details" and the same applies with seal design. Viton has been around since the 1950's and since then has undergone a lot of development in formulation for specific applications resulting in a whole family of Viton materials. It is correct that some formulations of Viton are not applicable for steam and hot water use but others are. May I suggest that you check page 5 on this website: http://www.rtvanderbilt.com/VTE-H68134-00-F1105.pdf

"Selecting a Specific Type of Viton Flouroelastomer"
"Differences in Fluid Resistance Between Types of Viton Products"

You will see that the Peroxide cured types of Viton have an excellent rating for Aqueous Fluids: Water, Steam etc.

And speaking of details you will notice that there is also a Bisphenol cured group which I think is the same material that is getting a lot of bad press lately as the cancerous agent used in baby bottles etc. Maybe some chemist in HB can verify this?

I hope this helps
Geoffrey