# Is OPV mod necessary for a pre-Philips machine?



## bronterre (Mar 25, 2014)

I know that a lot has been written about this topic, but it's difficult to get a clear idea from some of the lengthy threads. So, if you'll excuse a naive question: do you need an OPV mod for a pre-Philips machine? I ask because it can be inferred that post-Philips machines are set up for pressurised baskets and therefore the mod is unnecessary or less necessary with a pre-Philips one.

When I started with the Gaggia, I thought the Dualit grinder I was using the bees' knees, but was sadly disabused after coming on here. The finest I could grind the beans still meant that a double shot went through in about 12 seconds. Since I bought the Mignon, I've got the shot within 25-30 seconds (and it tastes not bad) - thanks to the wise forum member whom I'm afraid I can't remember who said somewhere that before considering the mod, we'd have to make sure that we'd got the grind right. So, is the issue with the pressure a matter of the speed of the shot, or something else? And any other observations are welcome.


----------



## marcuswar (Aug 19, 2013)

The "mod" (or more precisely the adjustment) of the OPV is required on them all, pre and post.


----------



## marcuswar (Aug 19, 2013)

As far as I know the adjusting of the pressure down to 9-10bar is purely about taste. Obviously lower pressure will result in a slightly slower pour (so you may well have to make your grind slightly coarser) but that isn't the actual intention per say. When I adjusted mine down I found that the taste of the coffee became smoother and more balanced.


----------



## bronterre (Mar 25, 2014)

OK, thanks for your answers, it seems I was barking up the wrong tree. I'll have to face up to the prospect of doing the OPV.


----------



## marcuswar (Aug 19, 2013)

Having just reread your original post I'm not sure if you're saying you have a post Phillips machine with a pressurised basket? If so then you need to get a non pressurised basket and remove the plastic plug from the bottom of the portafilter before doing the OPV adjustment. The pressurised baskets are for getting supposedly acceptable espresso from pre ground coffee (which is far coarser than espresso grind).

I'd recommend a better grinder as well. If money is tight then even a cheap Hario Slim hand grinder would be better. Failing that you could try shimming the burrs your grinder to get a finer grind.


----------



## bronterre (Mar 25, 2014)

No, sorry I obviously haven't made it clear, I've now got a decent grinder, a Eureka Mignon, which does a good job compared to my old Dualit, and I haven't got a pressurised basket, just the original kind as supplied with the pre-Philips grinder. The point was I wasn't sure if the pressurised basket on newer models were the sort that required the adaptation.


----------



## marcuswar (Aug 19, 2013)

Ahh..my bad.. Reading on my phone with a small screen and bad eye sight









The OPV adjustment is dead easy to do. You need a 17mm socket to get the top bit off and an allan key to adjust the internal screw. You'll also need a newer portafilter than the old style double nipple gold one you show in the pictures. The reason being there is no place to screw the pressure gauge on to. Personally if you're going to have to buy a new portafilter you may as well use that money to buy a naked portafilter rather than just another version of what you already have. You can then make a simple drop in pressure gauge for it. I posted a simple article on how to do this a while back, I'll see if I can find it.


----------



## The Systemic Kid (Nov 23, 2012)

Classics with the pressurised baskets are factory set to 15 bar. Pretty sure pre-pressurised basket Classics I bought was sold as being 15 bar pressure in the spec sheet.


----------



## marcuswar (Aug 19, 2013)

Here's the link to making a simple drop in style pressure gauge for a naked portafilter; http://coffeeforums.co.uk/showthread.php?17102-Making-a-pressure-test-gauge-using-a-single-basket&highlight=single+basket

The nice thing about doing it this way is you can use it on any machine that you have 58mm naked portfilter for. I have used it successfully on both my Gaggia and my ISOMAC machines, plus there is no need to dismantle anything when you want to use it.

If you want to give it a go I have a spare set of washers and nut that I can send you free of charge if you want bronterre, you'd just need to buy the pressure gauage and blanking plate.


----------



## bronterre (Mar 25, 2014)

Marcus, it's very generous of you to provide all this very helpful advice and the offer of the nut and washers. I think I might have implied, since I was considering the OPV adjustment, that I was technically proficient. Fitting the Rancilio wand and then repairing it when I'd shredded the rubber ring was pretty much my personal equivalent of completing the Manhattan Project. I need to think about what's entailed and then if necessary come back to you, if they're still available. I wouldn't mind experimenting with some other beans before finally committing to adjusting the OPV. Thanks again for your help.


----------



## marcuswar (Aug 19, 2013)

No worries bronterre, you'll find that there are lots of very kind and generous people on this forum and I'm only giving back some of the generosity I received in the past









Don't be put off doing the OPV adjustment or making the pressure gauge , if you can turn a screw or drill a hole (for the pressure gauge build) then you can do them both easily. If you've already successfully replaced the steam wand with a Rancillio one then you are more than qualified to do either of these other jobs. You are probably correct that you should get used to the machine as it is now before changing anything otherwise you won't know if what you've changed has made an improvement or not. If you want the washers and nuts at a later date just send me a private message with your address. To keep things simple I'd recommend you simply buy a blanking plate rather than try to re-use a single basket, basically you then just need to drill a hole in it, put a washer either side, push the gauge neck through and tighten the nut. Using a blanking plate also means you won't have to worry about the epoxy glue melting if using on a hot machine.


----------



## Charliej (Feb 25, 2012)

Sorry to disagree here, but when checked, just to see, my pre-Phillips Classic , bought new in 2007 in Australia, was sitting nicely at 10.5 BAR so I left it well alone, it made some excellent shots in the 7 years I owned it, so I guess the year of manufacture could be the key, or possibly as they all use the same Ulka pump then it's the pump pressure rather than the OPV pressure that were being quoted, as anecdotally the OPV on later models were only set higher to enable the use of ESE pods.


----------



## bronterre (Mar 25, 2014)

Thanks Charlie, that's interesting. I've looked at the sticker on the bottom of the Gaggia, and as well as a serial number, there's what I assume is a date: "05/2006". Would anyone else agree that the pressure might be OK for this date of this model?


----------



## Charliej (Feb 25, 2012)

I would have thought so, my Classic was a 2006 manufactured one, but wouldn't have been sitting on the shelves long as it was bought for my 40th birthday in Feb 2007.


----------



## marcuswar (Aug 19, 2013)

My gold classic from 1997 was definitely set too high , needed a good 3/4 turn of the OPV screw to bring it down to 10bar static!

Best advice would be to stick a pressure gauge on it and see what it says.


----------



## bronterre (Mar 25, 2014)

Ah, OK, I can see that this isn't as straightforward as I'd hoped. You're right Marcus, I probably need to try a pressure gauge.


----------



## marcuswar (Aug 19, 2013)

There are a couple of people on the "pay it forward" section who are loaning out their pressure gauges free of charge... only issue for you is the old style portafilter that won't allow you to screw on the pressure gauge. As I say, if I were you I'd buy a bottomless portafilter and then use a drop in gauge. I can loan you my drop in one if you want for the cost of the postage, but to be fair you can probably build your own for not much more than the actual postage costs.


----------



## bronterre (Mar 25, 2014)

Hi Marcus, sorry I took a while to get back. I'll continue to experiment with beans and taste; if I feel I need to change I'll follow your advice and possibly take up your kind offer (see previous posts on DIY skills - at least I'd know what I was getting would work).


----------



## marcuswar (Aug 19, 2013)

No worries. Let me know if you want to borrow it at some point


----------

