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Thread: Microcimbali Liberty - Lever adventures

  1. #1
    Senior Member artman's Avatar
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    Microcimbali Liberty - Lever adventures

    I recently finally cured my curiosity on the marvels of the lever and picked up a Microcimbal Liberty!

    The machine looks pretty good, has not been used for some time and needs some minor touches in a couple of spots by the looks of things.

    What a cool looking beast:

    mcl.JPG

    The valve on the top of the machine is not sealing properly. Is this an anti vac valve or an over pressure safety valve?

    top valve.JPG

    Also, what boiler pressure do these normally run? This one kept going to 0.6bar and beyond, with the leaky top valve I turned it off. Looks like the pressure stat is adjustable via the spring pre load, similar to the pressure stats on the Junior models.

    Can't wait to pull on shot on this thing!!

    Cheers

  2. #2
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    Looks like a pressure relief valve. A google search should bring up an Orphan Espresso suggestion on how to fix this (no link sorry, not sure if it might be considered a commercial link).

    Cheers,

    Matt

  3. #3
    Senior Member artman's Avatar
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    Thanks. Need to get a deep socket to get to it. Bugger.

    Cheers

  4. #4
    Senior Member artman's Avatar
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    The top cylinder part of the pressure release valve unscrews from the lower body (that is screwed into the boiler).

    I unscrewed the top part and all that is inside is a steel ball with a very weak spring pre loading it.

    Inside of the pressure relief valve:


    Valve body in boiler. The ball seats on this.


    What boiler pressure do these normally run? This valve leaks almost as soon as there is any pressure. The spring is very weak but not sure if it is the seal or the spring. Maybe both?

    I tried chamfering the seat to give it a better seal with no real change. Might need to give that another go or find a rubber ball instead to help seal.

    I dosed the basket, used a little milk "jug" as a tamper (almost perfect!) and tried pulling a shot but with little success.

    Make shift tamper:


    The lever springs back up as quickly as it is released. My understanding is that the spring is what forces water through the puck and hence should rise slowly as pours?

    I might need to take it apart and have a closer look at the piston and seals etc.

    The journey continues...

    Cheers
    Dimal likes this.

  5. #5
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    I wouldn't chamfer the hole any more as it will decrease the pressure at which the relief valve operates, due to a slightly increased area of steam (and therefore force) operating on the ball.

    How long does the actual pour take, and what does the coffee taste like?

  6. #6
    Senior Member artman's Avatar
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    I only cleaned/created a smidge of an edge on the inside of the fitting (was a bit cruddy) to see if it would seal better, but fair point. Would be easy to make the valve adjustable by drilling and tapping a hole in the top of the housing and using a little bolt to adjust the pre load on the spring, or change spring strength.

    Coffee was crap as the the extraction was very long with hardly any volume.

    Need to confirm it is working correctly then get grind and dose in the ball park.

    Will keep playing.

    Cheers
    MattyRay likes this.

  7. #7
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    Looks like a cool machine, I'm jealous! :-)

    Cheers,

    Matt

  8. #8
    Senior Member artman's Avatar
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    Yeah they do look pretty cool and the simplicity of operation makes it quite unique (to me).

    Just got to get it working properly!

    Cheers

  9. #9
    Member 3rutu5's Avatar
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    looks great, i'm gathering it has a lever/spring arrangement and not direct drive like a LP? With my PV it took a while to stop it bouncing back up quicker than i would have liked, mainly because i was new to the grind/tamp/timing of a small lever.

    i had a guy in the states make me a tamper online in a site that sounds like eskie I had a laugh, took a week once i got some calipers and measured up what i wanted. I'm guessing the portafilter is anywhere from 44-49mm

  10. #10
    Senior Member artman's Avatar
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    My understanding is that you pull lever down, this forces water into the brew chamber and then the spring tension pressurises this water forcing it through the coffee puck (and slowly letting the lever rise again).

    That's why I think something isn't working quite right, When I pull lever down and then release it, it raises as quickly as I let it go, and hardly any water flowed through the puck. Also, once I powered off the machine (pressure kept rising) it wouldn't kick in again when pressure dropped and I switched it on. Need to check the operation of the pressure stat.

    It could just all need a clean and some TLC which I will give it once I get a bit more time.

    Re tamper, I need to get my father in laws old lathe cranking and have a play, another project!

    Cheers

  11. #11
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    Time for a new seal kit perhaps?

    Regards,

    Matt

  12. #12
    Senior Member artman's Avatar
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    Yeah possibly. I was told it had all new seals etc installed. I do have some new seals though so can change if required.

    Cheers
    MattyRay likes this.

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