I have a new 2011 Cremina. I sent this question to the Orphans, but have not received a reply yet so am posting here.

When pumping the lever up and down to warm the brew-head, it makes a sound on the down-stroke which sounds like metal on metal: if I had to describe it I would say it's somewhat like the sound of a large scissors being operated; or the sound of guillotine paper-cutter. I made a short video:



Is this typical and to be expected? While it sounds like metal on metal, it could possibly be the sound of cool(er) water being forced back from the brew-head into the boiler (but that's not really what it sounds like).

Note that this sound really is only apparent when the machine is pressurized when pumping the lever without coffee in the portafilter. On a slow brewing down-stroke it is not there. It's worst when the machine first comes up to temp on the initial stroke or two to flush the brew-head (when the brew-head is still cool).

Just wondering if I need to be concerned or if this is normal.

Many thanks.

There should be water exiting the group during the downstroke, but it's not apparent in your video. That said, I haven't noticed any similar noise in mine. The only metal-on-metal contact should be: 1) between the piston bolt and the group, 2) the bushings and the piston bolt.

I'd do a quick check to make sure that both parts are sufficiently lubricated and centered. It doesn't take much; a very light film of Dow 111 (orphanespresso.com) will do the trick.

According to Orphanespresso, the piston seals are the same between the 2011 and '67 models, so it doesn't seem that there would be any metal-to-metal contact on the piston itself.

Just to be clear, in my video I was only raising the lever 2/3 of the way up and stopping before any water started coming out of the group.

Just for reference, I do get something like "metal-to-metal" if I let the lever down too fast without coffee or resistance, and the machine is on with full pressure. That was very long ago and I rarely get those sound, it's only been like 3-4 times I got those so far in about 2-3 months. At first I thought it was some scales stucked in the piston, scoring the group cylinder but apparently(and thank god) it's not because I still get that once after fully rebuilding my Cremina. It's something else. I wouldn't worry if it's only making that noise once a blue moon.

I get this noise from time to time on my Cremina 67 and I'm a tad worried about it as well...

I have the new 2011 also, and I get this noise too. But not all the time. The noise reminds me of the old paper cutter boards when you lower the blade.

That sounds to me like it might be seals rubbing since inside of group is dry so there isn't water helping with lubrication there. What you can try is first raise lever to let some water out. Then perform half pumps but lower the lever slower. If these are seals making noise this should fix it...

If you are not allowing water to enter the group (and therefore, exit it) you are not pre-heating the group. The group is heated by water! How do you suppose the group would be heated without water?

The piston seals on lever machines are largely lubricated by water, not the little bit of whatever lubricant that is applied to them occasionally. That is why one should not operate the lever when the machine is not full of water and up to operating pressure. The pressure from the boiler forces water into the group, lubricating the rubber seals.

I can document the effectiveness of this technique by the fact that I never lube and very seldom change seals on my lever machines, and they last a very long time.

PC

Yes, it does seem to only happen to me when the group is "dry". Pumping water through the group does take care of the noise.

peacecup wrote:If you are not allowing water to enter the group (and therefore, exit it) you are not pre-heating the group. The group is heated by water! How do you suppose the group would be heated without water?

This is false. By doing these small pumps, you push the cold water that lies on top of the piston back into the boiler and in exchange, hot water is pushed onto it. I preheat the group this way all the time.