Introducing our La San Marco Leva 2 group, type 80, 1983. We spotted this on 30th and Belmont in 2002. A few owners later and we purchased the machine. Now we use it in our shop.
The LSM Leva has the ability to do one thing very well, to provide smooth and stable water flow to the brew groups. No Marzocco, or Synesso, or Slayer can match it. These newer machines definitely are advantageous, but no machine except a lever completely isolates the brew water from the brew line. Isolation means that for the majority of the duration of an espresso being pulled the brew water is completely separated from the water line.
The LSM Leva is a spring/piston lever. When the lever is vertical and the machine at rest, the piston is almost touching the shower screen. Pull the lever down and the piston raises, at the same time compacting two large springs. There is a point at the bottom of the pull where a part of the piston assembly, that has been pulled up, contacts a cam, opening a water valve, letting water into the shaft. The valve opening is controllable by the degree that the lever is pulled down. The valve opening is immediately next to the shaft. When the cavity is filled with water, the lever may be released and the spring exerts pressure on the column of brew water, pushing through the coffee. As soon as the lever is released, pressure on the cam stops and the valve is shut, completely isolating the column of water as it gets pushed through the grounds.
The fat tube leading to the back right of the steam boiler, carries cold incoming water into a heat exchanger tube, that hangs in the roof of the steam boiler, up in the steam. You can see where it exits the back left of the boiler and branches out to each group. The group has a cavity that is full of water, waiting at the valve to be let into the shaft. This cavity extends into the steam boiler in a dead end pipe. How efficient this is at keeping the water temperature stable we only have a feeling.
Anyway, this is the machine we use at our shop. We make experimental espresso’s, serve friends, occasionally take it apart and rebuild. When Matt Sperry started he rebuilt this machine. Now Alex is working on our three group, between deliveries and roasting/apprenticing.