I finally finished the installation of my custom needle valve kit from Sean Alcorn. It, paired with the Shureshot, now opens up a lot of capabilities that I didn't have prior, namely flow control throughout the shot. As it came stock, the restrictor certainly looked larger and the whole unit tended to act like a 'water cannon' to coin Nicholas Lundgaard's term for it. I placed a new 0.6mm ruby restrictor into the group neck and it's mated to a needle valve that I can control external of the machine (which is quite nice). Lots of Swagelok fittings and all the tubing is small diameter stainless steel.
Sean really did something quite remarkable, especially since my machine is here in California and he built it on his 3 group in Sydney, Australia. He went with only ruby seals instead of Viton. The pressure gauge now reads an analogue of the pressure at the puck. If I don't have the resistance of a coffee puck, the pressure gauge shows no pressure at all. With either a blind basket to adjust pump pressure or a coffee puck, I can monitor the pressure the coffee is seeing. It'll be interesting to pair this up with a Scace again now that it's installed and see the offset on the gauge.
Here's the first video of it in action. The shot was extremely good, especially for just dialing things in.
I'll keep toying with the various settings, likely increasing the pre-infusion time thru the needle valve longer without lengthening the total shot time. With the Shureshot, I can set each stage at a set time, and choose whether I'm flowing thru the needle valve or bypassing it. I can tail off the end of the shot like a Synesso by either choosing line pressure at the end, or I believe, line pressure thru the needle valve. More playing around to be done on that front.
The faceplate will need to be drilled so I can have the needle valve knob protrude nicely thru the front. It's nice to think I can adjust the restriction on the fly without opening up the machine.
All in all, this cost me about $800 (not including the Shureshot) and I'm glad I was able to get it. This one specifically was a one-off high grade build with all stainless components and better seals. He has others in copper and other more affordable parts he's considering selling. He's not planning on making these fancier ones on a production scale for now. It was a year of back and forth with him around the time I learned about the Shureshot, that I learned that he was also modifying his own 3 group Linea with needle valves that he intended to keep on his bench at work for his own use. I could have had a similar assembly on my machine earlier this spring if I was willing to go with what he already had on hand.