1958 La Cimbali Gran Luce Automatica (Hydraulic) [Finished] - Page 3

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
jimmc7010
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#21: Post by jimmc7010 »

How cool. That is a year older than me! :D ! It's a very intriguing design. I'll have to look into Cymbalta machines, as now I'm interested to learn more about them. That's quite the project you signed up for. Best of luck! Thank you for sharing.

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IamOiman (original poster)
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#22: Post by IamOiman (original poster) »

This is definitely the most complex machine I've worked on!

Valve cleaning and etc

I got the two valve screws that were really tight off after applying more heat (note the heat patina). They were still quite tight but they did manage to come off. To get the valve hot I clamped it only by the bottom, then moved it so I could clamp it better.






The valves and a few other parts were cleaned up, including the portafilter gasket holders. They were pretty grimy but I have been testing cleaning chromed pieces with my tumbler, and it turns out the chrome plating is harder than the pins, so the pieces clean up without scratching the chrome. This was about 10 minutes of tumbling (each, one could fit at a time) for the pf gasket holders.







The plastic fitting from the hydraulic group actually has an oring hiding inside a groove within the brass bushing. I am not sure what the size is but this differs from later hydraulic groups.



I have been probing at the original studs on the boiler lids. When I heat them a lot, I can partially turn the studs about 15 degrees back and forth but they become stuck beyond that. Investigation is ongoing but I hope to replace them with stainless BSW studs.
-Ryan
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austinado16
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#23: Post by austinado16 »

If you don't have one of those stud installation/removal sockets, you might really like them. Mine are from Mac Tools.
https://www.ebay.com/itm/385858011283

Are you soaking/spraying these stuck pieces with Kroil after getting them hot?

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IamOiman (original poster)
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#24: Post by IamOiman (original poster) »

I have been soaking them now since I attempted removal. I have a stud removal too, and the marred threads are the result of multiple attempts (but not too much so I let go more than I usually do and reinsert the tool).
-Ryan
Using a spice grinder violates the Geneva Convention
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IamOiman (original poster)
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#25: Post by IamOiman (original poster) »

This is the stud removal tool I was referencing. I managed to get 2 of the 6 group flange studs out (I didn't even try the one remaining stud since it was so eaten).



I was really curious if my threads are actually BSW, and now I'm second guessing myself because I can thread modern UNC bolts into various (supposedly) BSW threads with no issue. If they are true BSW threads then I can thread a female UNC nut on a male BSW thread, but NOT vice versa. However, I saw multiple male UNC threads of different sizes thread into BSW female threads without issue. I cleaned the threads of the two group flange studs, and outside of some rust gunk that cleaned out the tap was threading with almost no resistance.





One last nugget of info is the wobbler weight needs an extra tall 17mm socket, or the hex at the base of the wobbler weight fitting can not be reached.
-Ryan
Using a spice grinder violates the Geneva Convention
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IamOiman (original poster)
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#26: Post by IamOiman (original poster) »

Drop off bits for assistance
I got the bits that I need assistance with the metal doctor, primarily for stud removal + frame cleanup. The grouphead has nothing wrong but I just wanted to show how the flanges with the broken studs attach to the boiler.



Going back to the caps for the big pistons, it turns out one of them appears to be stainless steel after polishing a test section. The copper plated one will be very difficult to replate due to the inside recess where it would be difficult for the anode to reach without it being custom made (ie expensive). It will be cheaper to source another stainless cap I think but first I need to find it. I may have a source for that.

-Ryan
Using a spice grinder violates the Geneva Convention
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IamOiman (original poster)
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#27: Post by IamOiman (original poster) »

Cimbali sight glass shutoff valve hell

I was doing some cleaning of flanges that will recieve new gaskets, including the lower groups. It required a lot of scraping with a hobby knife then a wire wheel (outside) to get just about all the residue off. I elected to keep on the dipper pipes for the steam and hot water valves due to how little of a hex I could grasp, and I descaled that portion of the groups. I also got the other plastic fitting off that covers a gasket for the upper group.



What I was hoping to deal with relatively quickly was the two shutoff rods on the sight glass assembly. These rods will block the boiler (and any pressure) from the sight glass if it happens to break or possibly for servicing while not turning off the machine. These rods are surrounded by the same gasket twine that is on the group shutoff valves.


This is probably among the most miserable gasket materials to remove. It was hard like concrete for a while. My picks could not get good angles due to the rod blocking the center area, leaving minimal room to pick the gasket. I had to soak the sight glass fittings in citric acid to descale the stuck rods. I then had to use goo gone to soften the gaskets, pick the softened gasket, then apply more (and repeat 5 more times). The rods themselves were galled from years of use. The rods have a 7mm square head that is not easy to use without a special tool since the square head is surrounded by a nut compressing the horrid gasket material.

It took me 6 hours to take out the rods, not including soaking time. Please excuse me while my hands recover.





-Ryan
Using a spice grinder violates the Geneva Convention
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austinado16
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#28: Post by austinado16 »

My gawd man!!!

I don't know which is more impressive; the mechanical insanity of the machine, or your disassembly process. Speechless.

LittleCoffee
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#29: Post by LittleCoffee »

Loving this thread!
Let me get this right - Cimballi put two identical looking caps made from different materials on the same machine?!? Italian Engineering through and through - stunningly beautiful yet wildly crazy!

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IamOiman (original poster)
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#30: Post by IamOiman (original poster) »

I believe the stainless housing was a newer part that replaced the original at some point.

Custom gaskets

After some research and talking with someone who has worked on multiple generations of Cimbali hydraulic machines, I have determined that this old style of hydraulic group (including the Gran Luce, Rubino, and Pitagora) requires gaskets that are no longer available from Cimbali and need to be custom made, all of them pertaining to the group. I am using Seals-Direct again for sourcing my gasket order. The new gaskets I am receiving were spec'ed with the recommendation of Seals-Direct, and will be available for others to purchase once I confirm they work as expected (I'm not being sponsored for this).

I will note that the big piston seals (128mm) are unchanged and can be still purchased easily.

1) U cup gasket

This 12x7x3mm u cup gasket is used on the hydraulic valve body for the four pins, and also for the hot water and steam valves. I am purchasing 25 of them (I need 10 for this Gran Luce but will have extras for future projects).




2) L gasket

The L gasket is not used for sealing, but acts as a shim between the lower and upper group. I will need to cut a portion of it away for the volume selector, but the measurements are straight forward.





3) Cone gasket

The cone gasket at the bottom of the upper group is not the same size as new Cimbali machines. It seals the bottom of the big piston chamber and is covered by the plastic fitting with the o ring inside a bushing. The original gasket has a slightly larger ID at the bottom (21mm) vs the top (20.5mm). The new gasket will have a similar slope.





Pricing was not too bad, the most expensive one was the L gasket at around $5.50 a pop, but pricing may fluctuate. I also ordered some teflon boiler gaskets from the same supplier as I have found that the parts suppliers sometimes do not get the correct ID (the correct size is 215x200x3mm).

Overall I had four different gaskets made (piston seals, u cup gaskets, L gaskets, and cone gaskets) that cannot be sourced from modern espresso parts suppliers and also ordered the boiler gaskets. My parts order from my normal sources will be placed soon. This gran luce requires the most gaskets on a machine I've personally worked on. You can check out the full list here along with parts links to each piece.

https://docs.google.com/spreadsheets/d/ ... =272462067
-Ryan
Using a spice grinder violates the Geneva Convention
LMWDP #612