I just finished a rebuild of a Silvia v2 and everything seems to be operating properly, however when I went to test pressure at the group head by placing a blind basket in the group and measuring the water displacement out of the opv (method further described in the link) I got almost no water flow out of the hose (droplets after 15 seconds)? Im not sure what my group pressure is but it seems high. Also, Im not sure if my opv is failing to function properly or if something is wrong with the pump. I would guess the pump is fine and the opv is the issue. Does anyone have any experience or suggestions on how to possibly fix this issue. I could just purchase the $50 new opv found in v3 but thought I would see if there was a cheaper fix. I have looked at the "Silvia pressure mod" but I need to know what my pressure is at before modding it. Is it possible I overtightened the opv valve during reassembly so its not functioning properly?

I've heard distant rumors of a floating pressure measuring portafilter, is this so?


(http://coffeesnobs.com.au/YaBB.pl?num=1143622054) method for measuring group pressure

I'm assuming that your machine has a vibe (not rotary) pump. It's not clear if you tried to adjust the OPV or not? Usually there is an adjustment screw or nut & adjusting for an OPV drain rate of about 60 - 75ml in 25 seconds would approximate a pressure of about 9bar.

Or for about $20 you can buy a pressure gauge and the fittings needed to mount it to a portafilter for an accurate pressure measurement.

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The V2 OPV valves were not mean to be adjustable. You can adjust it by using spacing washers of varying thickness to compress the spring more or less depending on the adjustment needed. If I remember, you can use VW copper oil drain bolt gasket washers to space the OPV. But you will need to put together a pressure gauge. Make sure to get one that is oil filled, otherwise the needle will bounce all over and the readings will be useless.

In case someone in the future has the same issue I will let them know how I fixed this issue. The OPV is a very simple open valve construction and spring driven. You can literally adjust your bars by simply tightening or loosening the nut on the end. I had mine WAY too tight, so I added another O ring (Silvia opv mod) and tightened it to almost exactly 9 bars (265ml in 1 min....I may not sleep tonight) I see no reason to upgrade to the v3 valve as it is of little added benefit; maybe a little more convenient but that is all.

Randy G. wrote:The V2 OPV valves were not mean to be adjustable. You can adjust it by using spacing washers of varying thickness to compress the spring more or less depending on the adjustment needed. If I remember, you can use VW copper oil drain bolt gasket washers to space the OPV. But you will need to put together a pressure gauge. Make sure to get one that is oil filled, otherwise the needle will bounce all over and the readings will be useless.

They weren't? I thought one of the selling points of the V2 was the introduction of the adjustable OPV. My V2 was pushing 11 bar when I got it, and just by taking a wrench to it was I able to get it to 9.5 bar consistently (measured by an oil filled gauge + pf contraption).

They weren't? I thought one of the selling points of the V2 was the introduction of the adjustable OPV.

Not only possibly, but likely. As I mentioned earlier, imo, the Silvia version numbering system, evidently adopted by end users and not official with Rancilio, does not make a lot of sense to me, and so what I thought was V2 is evidently not reflect the generally recognized nomenclature of the masses. As evidence to that I offer this- the addition of the OPV would have deserved a version number, "officially," if it had been accompanied by the addition of a pressure gauge.