so it was all cold and grey this morning, and a friend had just left after we stayed up watching old japanese animations all night and eating cheesy goodness. it was now time to pull apart the microcimbali i had been eyeing off in the garage....

i disassembled my microcimbali up to the point of the piston spring and the lower group body. it is an older style, unlike ones i have seen in other forum posts or on orphanespresso's guide - the piston is not held in at the top with 3 bolts - it comes out the bottom. and there seems to be no clear way of unfastening the group head from the boiler / main unit.





the piston must come out from underneath - but i cannot see how to remove this part of the piston body (this is the group head, right?).... there are no screws or bolts under the group seal, through the head, or anything you can access through the boiler.



does anyone have any real experience with these machines and how to disassemble them?

the reason i am going this hard at pulling it apart is because i want to learn as much as possible about how these machines are made - i want to make one from the ground up (i have the skills, though the perseverance may be an issue....) this is why i am pulling it apart - mostly to understand. and as a sideline it is completely filthy and corroded and i want to restore it. thirdly, i am a compulsive puller-apart-er.
got to say, aluminium is awful - bad idea for a boiler....

i hope someone can help.
in thanks,
sean.


ps - i will post a proper pull-apart soon, when i have got a little further....

my guess you support the brass bit with the 2 pins, supply some upwards pressure to relive tension on the top bolt and unscrew the top bolt. then the piston slides down with the spring etc...I guess the 2 pins are for counter torque when you are screwing unscrewing the piston. This is just a guess though, probably OE know what gives...

sorry - the screws hold the shower in, and the top nut can be undone - it is just a stop for the spring....
if anyone has worked on one like this i would be grateful for some advice. otherwise i will start loosening the inside piston with a wooden block.

cheers.

That microcimbali looks really interesting. I'm curious if the silver collar (where the portafilter attaches) comes off the boiler body. Here are some pics from my microcimbali which is more like the ones seen on OE:





If the collar doesn't come off I wonder if the cylinder (with the holes for the screen) and the collar are positioned opposite from the one I have.

The cylinder on mine was stuck pretty firmly to the boiler. I wonder if your cylinder will just pop down from the spring tension if you unscrew the top bolt.

Good luck, curious to see what the piston and spring look like once you get them out.

pacman,
thanks for the pics - worth a thousand words!
the silver collar definitely comes off - there is a large seal to the main boiler body there. i am just not sure how it is attached - surely not pressure fit i would think, being part of a pressure boiler. i have loosened the top nut and it stays firm, even given a dozen solid raps with a wooden block and hammer - it does not budge. though no doubt, as you say, it is firmly stuck with corrosion at that point....
from outside it looks like it is very similar to your later version in the parts.

i will wait a little while if anyone gets back to me with experience of a similar expedition into the unknown, and if not, i will venture forth with more hammer raps on blocks of wood and see if i can loosen it at all....

not a screw in sight! i even tried "unscrewing" the whole lower part, thinking that perhaps it had a large internal thread - but a couple of sharp hammer raps on a lever and it did not turn.... stumped for now!

well that makes some sense. Have you sprayed lots of penetrating oil from both sides of the lower collar and the upper assembly?....really soak it a few times and let it sit for a day or two spraying aging occasionally.

Any clue under the pf gasket? Holes for a spanner socket perhaps? Either the cylinder sleeve or the big chrome ring have to screw off or out.

doug,
there are no holes under the pf gasket - no screws anywhere. i am assuming that it screws out in entirety - a big thread into the main body. i cannot think of anything else. i have tried bashed with the pf engaged, both ways, but nothing gives. i am soaking it in wd40, and not released, so have gone to acetone, and will give it more of a twist tomorrow. quite a weird system....
from other later models, it looks like the cylinder sleeve is trapped between the big chrome ring and the main body - i can only assume this is the same, and that the big chrome ring twists to screw out. cannot think of anything else....

Sean I also believe that piece would need to unscrew, now what direction is a mystery but hopefully standard counter clockwise (anti-clockwise)

Seems like a special wrench may be your best option, something that would engage the slots for the portafilter.

That, some diligent soaking and perhaps a little heat from a heat gun on the aluminum body may help.

I can imagine the brass piece threaded into the aluminum body for years would be an issue

albert paca wrote:doug,
i am soaking it in wd40, and not released, so have gone to acetone, ..

neither of these make good penetrating oil, they are "in a pinch" solutions. I've been doing well with 3in1's penetrating silicone spray...but basically any quality penetrating oil will serve you.