Background:
I started out in espresso with a moka pot on a lab hot plate in 1998 (my lab director always told me to buy the preground Illy, not LaVazza!), and progressed eventually to my current machine, a 2007 Izzo Alex HX mk II (*not* a duetto). Paired with an HG1 and weekly roasts on my Behmor, I fell into a laissez-faire steady state with my morning espresso routine (2-3 straight shots for me and 2 cappas for my wife) for years. In the last few months my Behmor started having some problems-- not unexpected after 10+ years of weekly roasting. I had to buy professionally roasted beans for the first time in a while, and I realized that, beyond the shortcomings of my amateur roasting efforts using a fading Behmor, I was missing something with my extractions. I wasn't able to reach the flavor profiles in the descriptions. What was going on? After years away from this site, I came back to H-B and discovered that people were moving into pressure profiling and flow control. And, amazingly, that espresso machine manufacturers are producing flow control devices that I can plug into my humble 13 year old HX machine (!). I went ahead and purchased the Quickmill branded E61 flow control device from chriscoffee about a month ago. For any who are wondering, the Quickmill device fits and functions perfectly well in a late-2000s Izzo Alex.

As most are aware, though, we E61 HX users usually rely on an Erics type grouphead thermometer to monitor shot temperature. So we have to give up the ability to monitor temperature if we are going to monitor pressure while using a flow control device. I experimented with pre-infusion and attempting pressure profiling for a while, going blind on temperature. It was an improvement from before, but I suspected it really was necessary to monitor temperature to make the most out of it. Conversely, monitoring temperature without pressure would allow for a guesswork pre-infusion, but not any meaningful pressure profiling.

So after searching on HB I found this brilliant modification to a Mara HX machine:
Lelit Mara - HX Profiler Conversion.

This looked like a significant project, but I figured in the worst case, I would have an excuse to upgrade my 13 year old machine. So I decided to embark on the HX Profiler Conversion mod.

Concept:
The brilliant idea (not mine, rather that of Mohninme) was to tap into the cam chamber of the E61 grouphead to create a port where tubing for a new gauge (pressure or temp, your choice) can be placed. The original modification had the tubing routed to the side of the machine due to the trim nature of the MaraX. In contrast, the Izzo Alex HX has relatively generous proportions:

(image: Bellabarista.co.uk)

After taking a look behind the front plate, I noticed I could fit a third gauge on the left side, below the existing boiler and pump pressure gauges. I decided to take the plunge.

Materials needed:
1) Pressure gauge. I wanted to purchase an Izzo gauge to match the others. However, the BSPP fitting permanently attached to the Izzo gauges I could find for sale was not compatible with any Swagelok-type fitting that I could find. So I purchased an Orman pressure gauge from espressocare.com. Now having finished the mod, I've found the Orman gauge to be responsive and with readings that match the Quickmill gauge that was included with the flow control device.

2)Swagelok fittings. These are adaptors that connect a metal tube on one side, and on the other are available in a variety of male and female thread fittings to make an attachment to a port, such as in the grouphead cam chamber. I used a 1/16 NPT male fitting for the E61 grouphead tap, and ⅛" NPT female on the pressure gauge side. I actually bought "Yor-lok" fittings that are Swagelok compatible, from McMaster-Carr.com.

3) ⅛" stainless tubing. I used 0.028" wall thickness. The volume of water in the tubing affects responsiveness of the pressure gauge, so it is better not to have a larger-than-needed tube inner diameter nor overly long stretch of tubing.
4) NPT to BSPP adapter since the pressure gauge had BSPP male thread, and I needed a 90 degree BSPP elbow as well. Purchased these fittings and a few basic supplies all at McMaster-Carr and/or espressocare.com
5) Proper drill bit and thread tap for the E61 grouphead tap
6) Hole saw to make the hole for the new gauge in the front plate (I used a 1 9/16" ~40mm Lenox bi-metal with arbor version off of amazon)


Process:
Having purchased the needed materials, what I proceeded to do was to follow the advice from the aforementioned thread (Lelit Mara - HX Profiler Conversion). Drilling an approximately 5/16" hole into my E61 grouphead was nerve wracking for this non-machinist, but boring into this big hunk of brass turned out to be easier than making the holes in the stainless steel front plate. After drilling the holes, it was a matter of connecting the tubing and fittings, checking for leaks, and making sure everything would fit into the proper place in the Alex case among other tubes, the boiler, etc. The project took about 2 ½ days.

Photos of the process:

Hole drilled into E61 grouphead cam chamber (background), with new fitting in place and SS tubing about to be attached:


Pressure gauges being tested; both are reading approximately 7 bar. The dark Quickmill gauge on the grouphead, and the new Orman/Pompa gauge sticking up behind the front plate. Yes, they are tilted and/or upside down. Function of the new pressure gauge seems very good, no different from using the original Quickmill gauge mounted on the grouphead--I had them both in place for a while to compare readings. (Please don't judge my extraction, this was for testing only):



New hole has been cut for third gauge (bottom):



This is how deep the fitting on the new gauge protrudes. The new gauge almost, but doesn't quite, fit in the new bottom cutout position on the bottom because it is deflected by contact with the boiler. I realized that aside from space for the gauge itself, the various associated fittings and adapters for the new gauge actually protrude fairly deep (50-60mm) into the machine, so it is important to account for this necessary depth in planning where to put the gauge:



This shows the location of the three pressure gauges post-installation. I had to move the boiler pressure gauge to the new hole on the bottom. The new grouphead pressure gauge had to be placed in the middle position because of the deep protrusion of the new gauge's fittings. The ⅛" SS tubing connects to the new port in the grouphead, just below the HX tubes:


Outcome:
Here is the Alex post-modification. I feel that the new gauge (middle position) looks to be fitting in pretty well with the rest of the machine:



I found that the diameter of the new pressure gauge was just slightly smaller than the old gauges, so it pays to double check the gauge and hole saw diameter if moving any of the gauges to a new space.
As far as what matters - how the espresso tastes - I feel like I've bought a new (better) machine. I am getting flavors and sweetness I never had before, due to this new ability to combine temperature management with pre-infusion. As far as true pressure profiling (such as replicating a lever profile, for example), I am still working on the technique which others seem to have mastered with the E61 flow control device.

In other threads, people have wondered how stable the temperature would be for an E61 HX handling a long (ie., 20 second) preinfusion followed by ~30 second or longer extraction. In my experience so far, which is only about one week, I have found that the temperature stays stable +/- 1-2 deg F for the first 50-60 seconds (ie., through 20 seconds of preinfusion and then 30-40 seconds of extraction), and then starts slowly increasing by about 1 degree every 4-8 seconds. This makes sense as the water flowing to the puck has been slowed down and has more heating due to exposure to boiler temp in the HX. An extraction taking longer than 60 seconds is usually not something I am trying to do, but this temperature ramp-up may affect people looking for profiles that have very long pre-infusion with long extractions.

Conclusion:
I'm glad I undertook this project since it has extended the life of my Izzo Alex and has greatly improved my daily espresso. It also increased my joy in using the machine, since there is a manual pleasure using the flow control device during a shot.