Rotary pump mod for Rancilio Silvia Pro - flow restrictor?

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by dfuller »

I was originally planning on sticking a Procon Micro Vane pump into my MaraX, but it was just barely too large for the frame, so that idea got canned.

I still have the pump, though, and with a Silvia Pro on its way to me, so that got me thinking: Can I make it work in the Silvia Pro? The space problem seems to be less concerning given the machine's slightly greater width (25cm vs 22cm) plus the greater internal space for the power supply (a 24V switching supply).

The concern now, though, is whether or not it would turn the machine into a puck destroyer. I don't know how much flow restriction there is in the Silvia group, so that's the main concern. There isn't much of any...

With the MaraX, it would have been a simple matter of adding a flow control device to the group, but I worry I may have to add a restrictor somewhere in the plumbing on the Silvia.
So - does anybody know if there's much in the way of restriction, or would rotary-ing this thing turn it into a water monster without additional mods?

UPDATE: I found a drawing of the Silvia group. I'm going to need to add a flow restrictor of some sort, because without some kind of needle valve, this will destroy a puck pretty handily. I figure with a small amount of work, I can add a pipe between the stock OPV and the boiler with a gicleur, LM style.


#2: Post by Caffeinesweats »

Just found this and thought it was a cool idea. Any luck with the flow restrictor and a rotary pump on the Pro?


#3: Post by Pressino »

The main difference between the rotary pump and the vibe pump is that the rotary builds up pressure more quickly and maintains it more evenly than the vibe pump. You can adjust the pump pressure on the rotary pump, but its build up time is still shorter than the vibe pump. The faster pressure build up means you may lose some "pre-infusion" when you make espresso on the Silvia, but I don't see why it will necessarily make the machine a "puck buster." The Silvia group uses a 3 way solenoid and has a "jet breaker" just above the shower screen. I suppose you could reduce the chances of busting channels in your puck by using a puck screen.

I may well be wrong about this, in which case someone will correct me. :oops:

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#4: Post by borrik »

What should be improved? What are the expectations from such upgrade?? Just to have Frankenstein machine with rotary pump inside?