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

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IamOiman
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#1: Post by IamOiman »

Post Original Restore, 17 December 2023 Edit

I created a table of contents to better navigate this thread in the future.

Disassembly and Cleaning
Front Panels and Valves Disassembly
Sight Glass, lid, and group pipes
First group taken off
Remaining boiler connections
Remaining chassis disassembly
First group disassembly
Big Valve 1 Disassembly
Group inspection
2nd block disassembly and cleaning + pistons

Lower group castings

Boiler bolts and flange removal

Cleaning the flanges

Cleaning fasteners and etc

Valve cleaning and etc

Drop off bits for assistance

Cimbali sight glass shutoff valve hell

Custom gaskets

Gasket punch and power switch
Boiler fasteners and body panel disassembly

Body panel overview

Body panel frame painting and broken screw removal

Cleaning and polishing chrome panels


Reassembly
The Beginning of Reassembly
Polishing Stainless Steel

Chassis Assembly
Group layout
Switch assembly and gasket fit test
Group valve block testing and new element
Complete group valve block assembly
The US Patent on the Cimbali Hydraulic Group
The selector assemblies
Dipper anatomy and water inlet
Hydraulic group assembly
Hydraulic Circuit pressure regulator plan
Boiler lids and group flanges are retrieved
Hydraulic Group mounting
First testing of hydraulic circuit
sight glass and water inlet pipe
Almost ready for testing

Testing/Operation
First Heatup and First Shot

Draining the boiler
Volume mystery and the proposed solution
Heavy duty testing/Brian Quan visit AKA, Dungeonfest 2023
More testing
Explanation of the Hydraulic Group
Checking out the leaky pistons
Further troubleshooting and questioning continuing to use the Gran Luce
The End (for now)


Original thread

I was pretty curious about hydraulic machines for a while now, and decided my first project would be my 2 group Gran Luce Automatica purchased as part of the group of machines from New York state. It is in good original condition, but I saw that someone has worked on the machine at least after June 1987 according to the heating element, which is pretty surprising to me that someone would use one so late.






Exterior Panel Disassembly
Because this is my first hydraulic machine, this will be extra detailed so I can keep track of things. The panels on the machine is one big assembly that hinges open after removing three phillips screws on each side of the front and two countersunk screws on top. The cup tray comes off in four pieces, the two directly behind the groups each have two screws that need to come off.






I removed the asbestos insulation already, but there was also a fiberglass sheet nestled between two gas shield panels. I removed it relatively in one piece but a few fibers are stuck to some rust.



-Ryan
Using a spice grinder violates the Geneva Convention
LMWDP #612

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

Front Panels and Valves

To take off the backsplash and front panels, the tube going to the top of each group needs to be loosened. While taking off the top panel, the two black shims surrounding each group cap can also be slipped off. The four screws holding the top panel are the short type. On this machine, most of the body panels will use a short or long phillips #10 screw (3/8" or 1/2" thread length).





The backsplash comes off after loosening eight screws total, where the bottom four secure two brackets. The side panels are each secured by one screw after the backsplash and top panel are removed. The sight glass cover needs to be removed in order to access the right screw when facing front. The cover needs to be pinched to fit through its hole (which is kind of not good if the cover is brittle).




The lack of front panels reveals the groups. There is a wild looking valve block on the side of each group. There are two valves connecting to the neck of each group casting that each go to steam and hot water. The hot water pipe has a bracket on the frame, and it needs to be loosened before it can be removed.






-Ryan
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#3: Post by IamOiman (original poster) »

Sight Glass, lid, and group pipes
The sight glass is attached by two 'arms' connected to the boiler. The bottom arm has a pipe connection for the gas regulator. The water inlet pipe needs to be removed in order to remove the entire assembly as one piece. The rhombus shaped gaskets sealing the arms were hardened enough to pop off as one piece. I noticed the water inlet pipe had two locations where it appeared to have burst. I'm not aware that this machine was stored in a below freezing environment, and this is the only pipe I have seen that looked like this.









The first boiler lid popped off after too, which was secured by 3/8" bolts. The first thing I checked was whether it was made of brass. Fortunately it appears to be in fact made of brass after wire wheeling a few spots, but it does have the really heavy duty plating on the exterior.



I wanted to take off one of the groups, and I had to take off multiple pipes before I could begin loosening the group boiler nuts. One pipe goes to the top of the group cap, one goes to the water circuit inlet, and one goes to the water circuit outlet. There is a fourth pipe I left connected that goes to the bottom of the group cap.







The group was pretty stuck, but there were two gaskets stacked between the neck and boiler so I could wedge some thin tools to separate the group from the boiler. To be honest I've seen far worse rust on those studs from other machines.

-Ryan
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#4: Post by IamOiman (original poster) »

First group off
The group is pretty heavy. That big valve block is incredibly complex in order to direct water into the group to either make single or a double espresso. Besides the fancy valve block and upper group, this is the first Cimbali group I've seen that has four studs instead of three to connect the upper group with the lower group casting.





While moving the machine before I heard water sloshing around inside what I originally thought was the boiler, but it is actually the upper groups. I had to open up the cap and place the group on its side to empty what I estimate was a pint of water. There is a little spring that needs to come off first before the cap can fully be removed.




It was crusty inside. There is a really fat piston inside that slides up and down. There are portions of the group that do not appear to react well with water but I will need to clean stuff up first to inspect them better.





This is where I'm ending for the day. This machine is pretty complex but hopefully I can get stuff torn down soon. Probably the most 'wtf Cimbali!' moment was discovering some boiler bolts have circlips holding the individual boiler bolt from sliding out. But why

-Ryan
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austinado16
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#5: Post by austinado16 »

Beautiful machine, and the mechanicals are amazing! Thanks for all the photos!

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#6: Post by IamOiman (original poster) »

Remaining boiler connections

Getting right back into it, I took off the other boiler lid with the heating element, manometer, and wobbler weight. The wobbler weight has an aluminum cup to collect water from the release of boiler pressure that has a tube going to the drip tray. It is secured by a 34mm jam nut that was hard to get to but fortunately was not very tight. The pipe on the bottom of the cup needs to be sufficiently loosened or it will not lift out and fouls with the wobbler weight fitting. One of the two nuts securing the wobbler weight to the boiler lid needed a thin wrench to access. The studs were pretty crusty and unfortunately are too worn to reuse (in fact they sheared off afterwards from just light tugging and now need to be drilled out).







The second group had its gasket shimmed with a razor blade. One of the three neck studs sheared off due to corrosion eating away where the gasket lays, so the group more easily separated from the boiler. However, because the steam valve pipe is pointed upwards inside the boiler, and the water inlet for the group was facing downwards, I could not immediately remove the group due to these pipes not being able to fit through. To fix the situation I had to remove the dipper pipe after soaking and heating it for a while.





-Ryan
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#7: Post by IamOiman (original poster) »

Remaining chassis disassembly

The lower front chrome panel comes off after the power switch, valve inlets (input/output of the hydraulic circuit, drain, and water inlet), and two screws are removed. It was a snug fit to the frame so some tugging was involved. At this point I brought the remaining machine outside for removing the bottom screws.






In the pic above there are five (minus one already removed) phillips screws for securing the lower rear ribbed panel. The phillips drive in each screw needed scraping due to dirt accumulation. The four flathead screws go directly into the aluminum boiler supports, and I have seen on other Cimbali machines that these often snap off. I was lucky and could remove all of them eventually.


The front frame had four bolts that also needed to come out. Two of them broke (the top bolt on each side), so in total I have two screws that snapped on the aluminum boiler supports. Which is definitely not the worst outcome. I still need to take out the boiler bolts for the lids and I do believe the inner support back pieces for the groups can come off, so that will need to be worked on later.






The second group was drained of water and dried before being brought downstairs. I had to use Bessey clamps to coax the group cap off the piston seals.





I've gotten pretty far in a short time, and I'm curious to see what further disassembly will reveal.


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

Group 1 Disassembly

These hydraulic groups are quite hefty. I weighed one with some of its pipes and fittings taken off and it still weighs 20lb. To take off the upper group there are 4 studs that connect the top assembly to the bottom casting. I first took off the big piston that is held in place by a 20mm nut. Of the 4 studs, 2 of them hold the big valve block that can slip off when two nuts on the thread are loosened. All studs were removed, and I was originally thinking they were M6. However, they are an imperial thread that is 1/4" - 20 TPI. There is also a possibility the threads are Whitworth instead of SAE (where everything is the same except for thread pitch, 55 vs 60 degrees respectively) that I still need to confirm. There are probably other fittings on the machine that will tell a similar story.








With the four studs off the entire upper group can slide out along with the pistons and piston rod. The lower assembly for the big piston appears to be aluminum or something that can corrode. In the middle is a threaded plastic cap compressing a gasket and its shim for sealing purposes. There is a rubber shim on the bottom of the housing too and also holds the selector for shot volume.






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

Big Valve 1 Disassembly

This remarkable block of brass has lots of caps, fittings, and screws that need to come off for cleaning. The camme, its handle, and spring come off first. All of them are covered in a heavy smelly grease.








The valve block has four threaded caps on the bottom holding a spring valve each that the camme pushes down to open them during brewing. They were quite stuck, two of them in particular, due to the years of hard water deposit buildup. I had to descale the block a few times and use a lot of heat to get them all off.








After some gasket scraping everything was degreased (for parts that needed it) and tossed into the metal tumbler. This is just one portion of one group. There are a ton of other fittings that need to come off for cleaning too.




-Ryan
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austinado16
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#10: Post by austinado16 »

It just keeps getting better and better!!