1958 La Cimbali Gran Luce Automatica (Hydraulic) [Finished] - Page 2

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

Group inspection

I've been checking out the group caps more after seeing the nasty grease inside. Fortunately it all just wiped off, but one of the two caps has some chrome flaking inside where the piston seals slide against. knowing flaking chrome can damage cylinders over time this will most likely mean I need to rechrome the cap or source an undamaged one.






The other oddity is the base of the hydraulic group (where the chromed caps are placed) appear to be aluminum with a brass insert for the piston rod. There is definitely some wear where water normally hangs out during operation of the machine. Since these groups cannot be easily drained I presume some of it occurred during storage

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

2nd block disassembly and cleaning + pistons

I took apart the second valve block much more easily. No acid bath soaking was necessary, just some heat. The plating on this block is also in much better state. I wanted to note the camme on top has a pin securing it to the rod. It appears to have been either two pieces originally or snapped at some point. I also had to scrape off some gaskets. If the blade can get under them then often the gasket will pop off as one piece or large chunks.








The valve block was degreased, washed, descale, and tumbled. I did not need as much work done for this one to clean up well.





I also cleaned up the pistons and rods. The top pistons parts are plated brass while the bottom small pistons are just unplated brass. The piston rods are very snugly screwed onto the bottom pistons so I left them as is. The piston seals are the older style that are thinner and are not commercially available by Cimbali. I have gone instead to a place called Seals-Direct that produces replicas of the out of production seal. They are made of NBR, and I will see how they turn out! Chanik from Kaffee-Netz developed the measurements for these seals. https://www.kaffee-netz.de/threads/die- ... no.125048/





-Ryan
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austinado16
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#13: Post by austinado16 »

Amazing work you're doing!

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

Thank you!

Lower group castings

The lower groups are now mostly apart. There are multiple fittings that fought me but eventually came off, including the one way valve in the group neck, the screw plug for capping the hole drilled for the inlet into the group bore (even the one with the messed up drive head), and inlet dipper tube. I left the pipe for the hot water/steam valve because of how little of a hex head I can grab and it's very tight. I am also leaving the one way valve seat inside due to how tight they both are, and I can simply replace the teflon gasket in the future. There is also a second one way valve for each group that is in the dipper tube. I'm really curious as to why Cimbali doubled up on that. There is a 16mm ball that presses against the teflon gasket acting as the one way valve, two per group.








The shutoff valves have one of the nastiest gasket materials I've ever dealt with. Super hard, does not get soggy after a soak, and was a complete b*itch to remove. It revealed a washer on the bottom of each fitting in the end, but I have two more of these horrid gaskets to deal with in the sight glass.



So far I've been working on the groups and valves. I have not even touched anything boiler related outside of initial disassembly, but the lids will need some work. I have the big body panel chassis on my shelving for now. I am also dealing with a very stuck plastic cap. I am hoping to potentially have new ones made in PTFE since the original is of similar hardness.



-Ryan
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austinado16
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#15: Post by austinado16 »

The casting work, and mechanical design of this is mind blowing. I'm also blown away that any of it can be disassembled, as old and exposed to heat and water as it all is. Great job! You're absolutely the master of finesse.

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

Heat = expansion = more likely to loosen :lol:

Boiler bolts and flange removal

I checked out the boiler today and see what I could remove. The boiler bolts were held by retaining clips but none of them were too rusty and I could take them all out. I used an external ring clip tool to slightly open the retaining clips to slip out the boiler bolt. The aluminum frames do not come off since the boiler lips were formed after installing them, and they are secured in four spots at 90 degree angles by interior boiler indents with a rivet on the exterior locking into a recess.



The bigger focus was taking out the interior group flanges. I saw a few Cimbalis where the flange was soldered with lead (like one Paul Pratt worked on years ago), but mine uses a big gasket instead between the flange and interior boiler surface. To remove them I had to heat them up a lot, let them soak in some penetrating oil, heat it again later, and using a long flathead screwdriver I struck the tool into the gasket material itself. This forces the gasket to expand against the flange and boiler such that I could start peeling them away from each other. I also had to strike the bolts a little to loosen them from the remaining exterior group gaskets.





There was apparently more rust than I expected! Even before removing the flanges I saw rust tinted gasket at the edges when peeking inside (and you can see in the pics at the corners of the gasket especially). These bolts are absolutely compromised and will need to come out. We'll see how many break, but I expect at least 3-4 will not come out in one pice.


-Ryan
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patrickff
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#17: Post by patrickff »

As always, Ryan, thank you for documenting your progress.
Always a pleasure to browse.
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IamOiman (original poster)
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#18: Post by IamOiman (original poster) »

Cleaning the flanges

I was pretty curious with the flanges so I worked on them some more. I peeled off the old gasket, and they were dried out enough that they relatively came off in one piece (but broke them up to fit in a baggie). The rust was definitely from the bolts getting eaten away over time.






I descaled the flanges and confirmed they are made of brass. I attempted to remove some of the better looking studs, and after heating the crap out of the flange I managed to remove one with my impact stud remover. I am soaking the other studs before attempting to remove them. At this point I am getting pretty confident that these are Whitworth fasteners after my on hand SAE die did not want to thread on easily on good threads. The group studs are 3/8 16 TPI x 55mm.




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

Cleaning fasteners and etc

I took off the manometer pipe this morning with lots of heat. It definitely needs cleaning from the scale buildup.



The manometers needs some care since they are both not set to 0 right now. The boiler pressure manometer will probably be the more easily serviced because the hydraulic pressure manometer appaers to have been leaking and has a crack in its solder. Its bourbon tube feels much stronger than the boiler manometer. I thought nothing was written on the hydraulic manometer but I very faintly saw 58-1 (possibly, could be a different month).




The selector vave has two positions for a camme to be pushed inwards or outwards to select one or two espressos. There is a phillips screw on the side that presses against a shim and pin that allows the selector to only be changed when in a specific orientation that has a slot milled in the camme.



I degreased both selectors and cleaned a lot of screws and some valve bodies. It did not take long in the tumbler to clean the pieces, and I also tried some steel fasteners too that cleaned up well, but big pieces like boiler bolts mess with the magnet so I need to limit how many magnetic parts I can place in the tumbler.







I am going to need to resuse a lot of fasteners because I also did some measuring, and so far every single fastener has been the suspect Whitworth thread. I will need to try and source new stainless studs for the groups so they don't rust, and also potentially a few others if I can get them but the six 3/8 studs are an absolute necessity.

At this point I am about at 30 hours of labor
-Ryan
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austinado16
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#20: Post by austinado16 »

I can't help but think to myself: A couple of guys were sitting around one day, and one of them said, "We need to make a machine that will dispense a couple ounces of coffee."