Olympia Cremina piston pressure gauge unboxing

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dominico
Team HB

Postby dominico » Dec 17, 2016, 12:32 am

Arrived just in time for a snowstorm weekend. Now I have something to do between strenuous bouts of snow displacement!

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It comes with coffee!
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Unfortunately I have to go with the stock La Marzocco pressure gauge. Since my machine is in an office the NAKED login would not have been appreciated. Too bad, because I like the steam punk look of the naked gauge.
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I'll let you know how it goes...
http://bit.ly/29dgjDW
Il caffè è un piacere, se non è buono che piacere è?

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dominico
Team HB

Postby dominico » Dec 17, 2016, 1:47 pm

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http://bit.ly/29dgjDW
Il caffè è un piacere, se non è buono che piacere è?

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sweaner

Postby sweaner » Dec 17, 2016, 3:04 pm

Well, that didn't seem to take too long!
Scott
LMWDP #248

www.coffeefreek.com

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naked-portafilter
Sponsor

Postby naked-portafilter » Dec 17, 2016, 3:41 pm

dominico wrote:<image>


The President is watching closely :-)

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dominico
Team HB

Postby dominico » Dec 17, 2016, 9:27 pm

naked-portfilter wrote:The President is watching closely :-)


The President is jealous, he wants a brew chamber pressure gauge now too.
http://bit.ly/29dgjDW
Il caffè è un piacere, se non è buono che piacere è?

Katoci

Postby Katoci » Dec 18, 2016, 1:17 am

I'm playing with it a few weeks for now and really like it. Experiencing with different pressure profiles surfaces the same coffee's different faces (subtle, but definitively noticeable differences). Still need a lot of time to learn how to use its full potential.

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dominico
Team HB

Postby dominico » Dec 18, 2016, 2:40 am

Katoci wrote:I'm playing with it a few weeks for now and really like it. Experiencing with different pressure profiles surfaces the same coffee's different faces (subtle, but definitively noticeable differences). Still need a lot of time to learn how to use it's full potential.

I see you are hitting 9 bar on your pull. It is very interesting because I have learned this week that my "muscle memory" Cremina shots hit a maximum of 6.5 bar or so and then slowly decline from there. This is something that I did not expect.
I'm having a lot of fun learning "what 9 bar feels like" and "what 3 bar feels like."

I'm playing with some new profiles too, such as "preinfuse at 3 bar for 10 seconds, then ramp up to 8 bar and pull the shot."
Previously I had found that preinfusing at specific pressures was pretty much flying blind, especially since at that stage there is no flow to watch to help you know whether you need to let up or lean on it.
I've liked my Cremina as long as I've had it but I've never quite been able to make coffee sing with in the way that I can with the President. This pressure gauge may change all that.

As far as assembly goes, it took me about an hour from start to finish, although I did have some hiccups that others probably won't have, such as a lever pin stubbornly refusing to remove itself, and the fact that I lost my snap ring pliers and had to get creative.

Naked-Portafilter has an "assembly" video which I followed; it is pretty good but since there are no textual instructions (at least not yet) I can list a couple "gotchas" I encountered.

First of note is that you will want to have your own piston seals available in case they need replacing or one breaks while you are removing it from the old piston. The kit does not come with its own piston seals. It does come with a piston fitting ring however which is extremely convenient for getting a piston with new V seals back into the group. I wish I'd had this thing 4 Pavoni restorations ago!

Second: I want to take some time to clarify this part since its not made obvious in the video, and its the one thing that caused me a bit of grief even though the fix wound up being rather easy. After you insert the new piston and shaft into the group, there is a small brass washer you insert into the top of the piston shaft and then you screw in the pressure gauge mount. Screw the mount in very tightly, and make sure you don't unscrew it when you are adding the pressure gauge. This can happen if you aren't paying attention while fiddling with the pressure gauge to get it to lock in at the correct angle. I made that mistake the first time around and got a slow leak out of the base of the mount. The fix was very simple: re-tighten the mount.

Here is an image of the shaft with the pressure gauge mount screwed in. The part at the top is what actually controls the tightness of the mount. The two nuts at the bottom have nothing to do with the mount or the seal. They are simply there to control how far the piston is allowed to travel down the shaft. Essentially they simulate the "shaft cap" that used to be there on the original shaft.
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Lastly: If you bend a snap ring taking it off, don't use it to hold the new lever pin in place. Due to the design of the piston pin braces, a bent snap ring will pop off when used.
http://bit.ly/29dgjDW
Il caffè è un piacere, se non è buono che piacere è?

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naked-portafilter
Sponsor

Postby naked-portafilter » Dec 18, 2016, 3:51 am

Thanks for your ideas and first impressions Dominick!

This kit is a very new product (tested/developed for more than one year though). That means we've made already two slight modifications (I sent the kit for Dominick on the 24th of Nov. and it took more than 3 weeks (!!!) to get delivered in the pre Christmas season).

1. We'd changed the design of the shaft/fitting which is sealed now with a rubber gasket, and there is no need to tighten it with a wrench.

The new sealing (rubber gasket) is seen in the assembly video at 5:35



2. Because of the different fork design of the recent Cremina we had to use (and manufacture) a different spring for holding the half pins (see video below). We use now only this kind of spring for all Cremina and the coming soon Pavoni versions. Installation is much easier with this solution and there is no more problem with popping of snap rings.



I thought installation is quite straightforward for insiders (user who do maintenance at home regurarly) but Dominico is surely not a newbie :-). Instructions/texting as planned will be added to the video above of course. Most probably after Christmas :-).

Gpinch1

Postby Gpinch1 » Dec 18, 2016, 5:34 am

Gabor, the videos are so well done!

Looking forward to seeing more usage feedback from everyone.
:)

jwCrema

Postby jwCrema » Dec 18, 2016, 11:28 pm

What an absolutely cool idea and I'm very glad you've posted this just in time for Santa. Or the cash Santa leaves behind every year.

I just cleaned the piston face/group head of my Cremina today and I long for that snap ring upgrade. I have a set of stellar snap ring pliers, but hosed them to the point I am going to run it without them. Until I acquire this upgrade I'm thinking about starting a group buy on those snap rings (used to call them circlips).