Post By Timbosaurus
Timbo's 1st restoration - La Cimbali M20
After all of the sweet-talking of Cimbali's on here (admittedly mainly from JavaB, and Java "has an unhealthy thing for Cimbali's" phile), I took the risk and made the BRILLIANT (ie: really stupid) decision to win an old M20 on ebay.
It was local, a good price and complete, but it's obviously done it's fair share of work and had a few leaks in it's time. It was pretty grubby under it's clothing, but after a few checks and a good clean of the group head, it made a decent coffee. I'm coming from a 6910, and while I was expecting a huge difference in some ways, I wasn't expecting such a huge difference required to HOW to prepare for a shot and steam the milk. So unforgiving, and I have a lot to learn The first thing to learn probably should have been "why an 11L boiler HX machine is not a sensible home espresso machine"....
Anyway, here are some shots of the condition as it stands, and I've received a bunch of spares from coffeeparts.com.au to start the resto (damn they are quick!).
Things that seems to work OK.
- Both steam wands (but have bought new o-rings/seals etc anyway)
- hot water wand (but have bought new o-rings/seals etc anyway)
- Manual fill
- Auto fill (when the level sensor is bypassed)
- HX and group bits
- Seems to have a new over pressure valve and anti-vacuum valve fitted
- Sirai pstat looks newer that the rest of the machine, but maybe it is just in a cleaner part of the machine
- wiring is in good shape
- procon rotary pump works (but does show signs of previous leaks)
- boiler doesn't seems to leak (but also shows signs of previous leaks, so I have new gaskets for the rebuild)
Things that need work
- Chrome on steam wands is not good, so trying to work out whether to rechrome or replace... either way will cost a lot
- level float (I'm hoping it's just scale, because they're not cheap either!)
- the pressure gauge (the pump side is OK, and while the boiler side does reacts correctly, it sits on half a bar when cold and about 2bar when hot)
- the frame needs a full clean/strip/paint and the stainless needs a good polish
- most of the knobs are floppy or broken
- many of the gaskets and connections show evidence of leaks.
- the rotary pump (made in australia apparently!) will likely need a new o-ring at least
But all in all, I think it should be a good base for a resto.
One thing i was wondering about was the material for the boiler... I was expecting to see an oxidised copper boiler like many machines on here, but this one looks more like an extruded alloy tube with a plate welded at one end, and a case alloy plate bolted at the other. Is this a higher/lower cost alternative to a copper boiler, or is it just that machines from different eras used different materials?
Last edited by Timbosaurus; 30th March 2015 at 01:23 PM.
So far, the dates i can get from the printing on some of the parts are 1989/1990, so I'm guessing this is of 90/91 vintage.
The rating on the machine is something like 6.3kw, but I've measured each element at 4.3A @ 240V from cold. Given the pump is ~150w, it seems to be more like a 3.2kw machine. So would the ratings on the machine assume a higher voltage across the elements (eg: 380V) to come up with the 6.3kw total? or should I assume that the elements have been swapped for smaller ones at some stage?
According to the parts list on coffeeparts the element should be 3750w, the 3 group takes a 5790w element which seems more in line with the 6.3kw rating. Perhaps the data plates were switched at birth?
When I picked up the machine it was fitted with only a 10A plug, which scared me witless given the 6.3kw rating! I disconnected 2 of the elements for all my testing (to be safe), but now that i've measured it at 4.3A per element, I'm comfortable running it on a 15A circuit.
Here is the plate which seems to line up with the boiler ID, and clearly says 6.3kw. I guess it'll always just be a mystery...