La Cimbali M21 Junior with Speedster Idro-Matic profiling mods

Need help with equipment usage or want to share your latest discovery?

#1: Post by DSpitz »

First and foremost I would like to thank every single human (and non humans) that contribute to this incredible forum! I've been a lurker for too many years to count and have all of you to thank for this wonderful machine I've modded more than 5 years ago. I've been meaning to post what I did to my craigslist find all those years ago, but I like to test things for a bit before proclaiming success or failure to build upon.

Way back in the time machine as we were progressing with outside the box pre infusion and more I really did think Kees did well with Idro Matic spring idea and ramp up so I wanted to somehow replicate that within the bullet proof animal of longevity of the LaCimbali m21 jr casa. I found this puppy on craigslist beat to crap and pretty much never cleaned internally for a good price. First step was to do a complete tear down, de-scale and order bags of replacement parts.

I am a Master Watchmaker of mechanical complications trained in Switzerland so I do enjoy well made mechanics to start as a base platform to mod. Now... if I can remember five plus years ago what I did to replicate the spring and incidentals, I'll give this a go, with pics and a video.


Don't be fooled by the externals:

A sign of wonderful tasting Spro! :D

Water flow:

Closer to the goal:

Lot's of pictures so I'll do multiple posts to carry on...

DSpitz (original poster)

#2: Post by DSpitz (original poster) »

DSpitz (original poster)

#3: Post by DSpitz (original poster) »

And the resulting after cleanup:

Parts for mod:

DSpitz (original poster)

#4: Post by DSpitz (original poster) »

I had thought and researched long and hard as to how to replicate the Kees Idro Matic spring and how to translate what I found to be a One Neuton of graduated pressure into a something that would fit inside the LaCimbali and keeping it totally stock looking. This machine is timeless and parts are readily available for another 30 years, easily.

The idea that has lasted in daily use for more than 5 years now was to utilize cylinder air shock resistors used in parallel, along with a super high end needle valve, to regulate the ramp up for a customized internal adjustment. I started using it externally but in the end it was found to have a sweet spot and placed internally. I also played with dual needle valves but after replacing the LaCimbali water restrictor in line restrictor with their new model small hole official part, it was simply, perfect. Haven't touched anything in years.

So I removed all the disintegrated boiler wrap and replaced it with a high temp better version and also wrapped many other areas including the resistors as they get hot.

I used these resistors and highly recommend them after much searching for quality versions at the right spring retention rate:
Sioux Chief 652-A

Some picts of where they are jammed in:

Needle Valve:


DSpitz (original poster)

#5: Post by DSpitz (original poster) »

Put in some lights and other small things.

There was a post on here way, way back as to flushing the group head and how to pull / program via volumetric dosing and executing exact temps with the 4 buttons on the front of the pad of the machine. It's been so long I don't have who posted that (Ken?) but this was spot on as he used a scace. If anyone is interested I can go through my routines as to flushing as I also did a deeeeeep testing on this persons advise, also with a scace.

My buttons on the front from right to left will give me 4 exact temps after a one hit flush on the button needed, for the temp needed, followed by using the center on/off button for the shot. Right button (double 100ml) 198 degrees, (single 85ml) 202 degrees, (left button double 45ml) 204, (left button single 30ml) 206. If the machine is left idle for long periods of time (mine is on for 13 hours a day) you'll need to do 4 of the largest flushes (farthest right flush button) as well as letting out some water from the tap, let it come back to pressure as you prepare your shot, and then pick your flush temp right before shot, lock and load. I use shot scale for time/weight.

This machine is on a timer that shuts down at night and turns on 2 hours before I come alive. When alive in the a.m. I will run the water tap for 30 seconds open or so, open the steam wand for 10-15 seconds and run 4 large flushes. This derails the problem with the pressure valve sticking that so many have. I do the same in the evening. The pressure build up in the boiler sitting idle for home use seems to be the culprit. Mine used to stick until I came up with this fix. Still has the original valve on the boiler.

When pulling a shot let the deadband come up to 1.1 before you pull as it helps nail exact temps.
Pstat is 0.92-1.1 dead band
Brew pressure is 9 bar after ramp but adjustable via needle valve, as well as the ramp time.
Machine is the rotary pump version being plumbed with water filters on input and a regulator in line.

Additional things I've found to be needed are better screens. I'm using the IMS screen and it was a game changer. I also highly recomend changing out your basket for a VST 15G. This combination works in combination with the 1 neuton ramp up.

I will make a video the ramp and post in the coming days. Thank you all again for all the love you've sent back this way!

DSpitz (original poster)

#6: Post by DSpitz (original poster) »

The internal needle valve can adjust ramp times considerably to your liking just as the Idro-Matic Speedster can. This test is done with a blind portafilter.