Going single spring on the LSM lever group

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TomC
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Postby TomC » Sep 20, 2016, 7:04 pm

I finally quit procrastinating and pulled my group apart today (big thanks to Jim King for the piston socket) and am quite impressed early on with the results. I'm kinda angry I hadn't done it sooner. Not only does it work a lot easier, the shots I'm seeing early on are a lot better in my opinion. Previously, with the almost 11 or so bar pressure exerted by the dual spring setup, there were two things I always disliked; the effort required to pull the shot made it slightly less fun to use than getting a root canal, and the power of the two springs snapping up often would result in an exploding portafilter out of the group unless I held the portafilter in my hand during the extraction. The amount of torque applied to the portafilter to seat into the group was more than enough to keep it locked in place, but the occasional surprise explosion and broken cups left me deciding to just hold on to it during the extraction as a fail-safe. Neither was very fun.

Second, and by far more important, is I'm already seeing better shot flavors and improved highlights in the coffee. Before, I had to grind finer for any given coffee, to tame the powerful two spring combo and that often led to flattening out the individual notes in the cup. Even with babysitting the extraction by retarding the spring wasn't always enough to improve the shot. Now (early on in the testing) it seems like I can just pull and release and focus on anything other than babysitting the portafilter and hoping nothing explodes off the group or that the shot's flow isn't ideal for that given dose. It's like having a classic Gaggia lever but a hell of a lot prettier to look at!

I'll rattle on some more as I go thru various coffees in the future, but for now I'm quite happy with the change. I pulled several shots this morning on the Linea on a coffee that I'm considering for a HB review and then switched to a quick dial in on the Leva and the Leva had the Linea beat hands down on the first attempt for flavor highlights and sweetness.

I measured a peak pressure of just over 6 bar using my homemade portafilter rig/pressure gauge. Previously, if memory serves me right, I was just over 10 bar on the dual spring.

One thing the Leva offers that other groups do not is this option to switch back and forth at will. It only took me about 20 minutes to do the job at a leisurely pace, and part of that was cleaning the piston and re-lubing the seal. I'm sure there's plenty of coffees that do better with the dual spring setup, but for now, I'm going to be happy using it as a single spring group.

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arcus
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Postby arcus » Sep 20, 2016, 7:24 pm

Very interesting. It makes you wonder why they went with the dual spring.

Javier
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Postby Javier » Sep 20, 2016, 8:30 pm

Great job, Tom! I have had the Izzo Alex Leva in my radar for quiet a long time.

If you don't mind, could you please post pictures of the tool you used to remove the inner spring? And maybe in a few words describe how exactly you removed said inner spring?

I wish there will be more info about the Izzo Alex Leva. The LSM group is so beautiful!!!

Peace!

Javier
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TomC
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Postby TomC replying to Javier » Sep 20, 2016, 9:51 pm

Jim King made a custom pin socket. Unlike his, my piston wasn't secured using Loctite type glue, so it loosened without a lot of cussing and banging.

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The steps are rather easy: Pull the screen clip and drop the screen. Then use this socket to unscrew the piston head from the bottom (screws off counter-clockwise when looking up at the group from below). Then remove the four screws that hold the upper group assembly to the group sleeve (main body). The upper group assembly will now easily slide out from the top.

Set the group down and measure the length of the end of the piston rod length from the end of the single brass retention plate (this is the part that holds the outer larger spring that retains the smaller inner spring within it, like a 2 step plate where each spring nests on it's own ledge). That piece just screws off and the two springs relax. Slide out the inner spring and put the plate back on ( it doesn't take too much pressure to squeeze the larger spring enough to get the plate to re-thread on. Tighten it back to where it was before ( I used a simple caliper) and clean and lightly lube the seal. Reassemble in reverse order.

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Chert
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Postby Chert » Sep 20, 2016, 10:30 pm

Adding a second spring to my CMA groups brought peak pressure up to 9.5. The three years that I've had double spring groups I've used the retarding technique quite alot. When I bring the machine back into commission in a few weeks, I will measure the two groups again.

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Balthazar_B
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Postby Balthazar_B » Sep 20, 2016, 10:52 pm

Hey, Tom, a couple of somewhat related questions:

1. How do you find the overall build quality of the Alex Leva. Although it's not the Izzo that would interest me most, sadly there's not a lot of info on the quality or long-term reliability of Izzos in general.

2. To your knowledge, does the Pompeii have the same double spring setup as the Alex by default? I'm mulling over the choices in spring levers, and I have to admit that even though it's a great honking big machine, the Pompeii double can be had for an amazing price from one of the site sponsors, so in terms of absolute value it has to be considered.

3. Have you found the variety of baskets, gaskets, portafilters, and other paraphernalia somewhat lacking because of the rather unusual 54mm size?

Cheers!
- John

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TomC
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Postby TomC » Sep 20, 2016, 11:00 pm

All great questions.

I mentioned previously in my first look at the Izzo Leva, that the build quality was the highest I've seen in a commercial lever. Thick stainless steel, higher gauge wiring, insulated boiler, extra features (active cup warmer/steamer) etc, really put it at the head of the class. While I never had any problems with my Strega, I mused that the Leva will likely outlast the Strega, due it it's robust build quality.

The Pompeii group is identical, so yes.

And your last question, unfortunately, yes, there's a bit more limitations to what's out there in terms of accessories. IMS has come up with some nice competitizione baskets for it, and I also have some of their prototype screens. But to be honest, I don't know if they really help anything. I certainly haven't noticed any obvious improvements, but I do like having fancy new toys to play around with. Even with my aftermarket screen, I still get a powerful, slightly uneven looking flush when looking at it sans portafilter, but if that has any negative impact on the shot, seems unlikely.

I'm kinda redeveloping a crush on my Leva again. It sat unused for the most part while I've enjoyed the Linea with the ShureShot timer. When I get the flow control modification on the Linea, it'll likely be a game changer though. The Linea as it sits is more of a water cannon.

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FotonDrv
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Postby FotonDrv replying to TomC » Sep 21, 2016, 8:31 am

Thanks for this write-up Tom, very informative on several levels.

Love the "Water cannon" analogy :mrgreen:
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JohnB.
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Postby JohnB. » Sep 21, 2016, 9:29 am

TomC wrote:I mentioned previously in my first look at the Izzo Leva, that the build quality was the highest I've seen in a commercial lever. Thick stainless steel, higher gauge wiring, insulated boiler, extra features (active cup warmer/steamer) etc, really put it at the head of the class. While I never had any problems with my Strega, I mused that the Leva will likely outlast the Strega, due it it's robust build quality.


Which commercial spring levers have you personally compared it to as far as the gauge of the stainless & wiring as well as other features go? As someone who has owned a machine with a 53mm group I'd consider the Izzo's 54mm group a big drawback.
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TomC
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Postby TomC replying to JohnB. » Sep 21, 2016, 3:06 pm

A few directly and several indirectly. It has much nicer build quality than the Quickmill (which, to be fair is more prosumer like the Strega I drew comparisons to). It doesn't fry switches like the Londinium (which also lacks the boiler insulation. PID, steam cup heater...). The frame is solid stainless steel instead of painted mild steel like your Bosco, plus the things noted above ( and you don't get active steam cup heaters until you step up to a two group). You have the benefit of being able to swap baskets and use the same tamper. I have the features noted above and had to get another tamper and a few baskets. Not a bad trade off in my opinion.

While a Bosco frame will likely outlast several lifetimes, I prefer the solid stainless construction throughout that are less likely to rust, and they don't have slaggy welds like this with big gaps in them.

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