# Big difference between two Gaggia Classic machines



## Grahamg (Oct 24, 2013)

Another forum lurker coming out of the woodwork with a bit of an odd post, but I've just had a really surprising experience with using two different classic machines and feel compelled to share and see if anyone has ideas on reasons for what I perceive to be huge differences between the two machines.

Just as background and something of an introduction:


I got 'machine number 1', an old (around 2003 IIRC) classic from a friend of a friend that was emigrating a couple of years back, and used it cluelessly for a year or two until the solenoid got blocked and the water stopped flowing completely.... whilst on paternity leave with first baby (aaaah!).

I simply could not be bothered attempting to fix it and potentially live without espressos and Tewdric of this parish was flogging off his old classic plus MC-2 for peanuts so I went and picked them up. 'Machine number 2' (around 2008 IIRC) was free-flowing and so I swapped over the silvia wand and just started using this. rn

Wife then booked coffechap for a training session as an anniversary present (her morning latte must not have been up to snuff!), and I just carried on with machine #2 until this weekend some 9 months later.

Finally cleaned out the solenoid on machine #1 and got it back in action this weekend and it is startlingly better.


It's obvious that #1 has had far less use, it's very clean and everything 'tight' - no wayward drips, few rattles and healthy humming pump etc. - it also has a massively higher steam wand pressure with no leakage whatsoever, completely took me by surprise as I've been used to a low-pressure leaky wand on #2 over the best part of a year. Another peculiarity is that on #1 the portafilter takes a good 1/4 turn or more to sit solidly in the group head taking no effort to engage it in 'threads' whereas #2 it's a bit of an effort getting it in and it's probably done up tight in barely more than 1/16th of a turn - if you don't do it firmly when empty and the machine warming up, the portafilter can drop out!

Now, I gather that there's probably a seal needs sorting for the leaky wand, but is there anything that can be done about the amount/pressure of steam?

I'm not using the portafilter that came with machine #2 but I remember that being the same in terms of a lack of movement in the group, is there anything to explain this difference?

There are some vague differences in design between the two machines, #1 has just one rubber pipe to draw water up and a little black nozzle, what looks like a return outlet, which you can see sends water back in to the tank whilst machine under pressure (when pouring shot or backflushing). Machine #2 has two rubber pipes in the tank but both go up through in to the machine casing (no nozzle), I though this was just two to draw up water originally but gather now that one is a return pipe. Logos slightly different but nothing noteworthy. One other difference is the portafilters, although both machines were bought used I'm assuming they're original. #1 has a PF with two holes in, and #2 with spouty bits that shot pours through - never used the #2 one as it annoyingly doesn't allow for anything but an espresso cup to be placed under!

Any idea why it would be so much better and what I can do to bring machine #2 (the spare now!), up to snuff? Or should I just forget about it and keep it purely for spares given that the cost of a new solenoid is almost what I paid for the machine?!

Cheers,

Graham

(this is a real sunday morning post isn't it?! baby asleep = interwebz)


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## Jumbo Ratty (Jan 12, 2015)

I would guess the portafilter not engaging as well in machine number 2 is down the the wrong thickness seal being fitted. A difference of .5mm can make a lot of difference here.

I would wonder whether machine 2 has had the OPV mod done and machine 1 not had the OPV mod done. This may have a bearing on your different experience on both machines.

as for the steam wand dripping, this isnt such an easy fix and costs in the region of £30 from the top of my head.


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## Grahamg (Oct 24, 2013)

Hadn't thought of OPV mod - highly likely that #2 has. Must read in to this mod a little to understand the impact.


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## timmyjj21 (May 10, 2015)

I have noticed the same thing before. Even after adjusting the OPV on both machines, the older one had more 'punch' when pouring and needed a significantly finer grind setting. I put it down to the older one having the brown coloured Invensys pump instead of a newer red Ukla. @MrShades had better results with an Invensys and pressure profiling with a dimmer switch from memory.

Other things to consider that may effect steam could be the level of lime scale in the boiler acting as an insulator, or the variation between steam thermostats which are set for 145 with a 15 degree range. One might have a thermostat that gets hotter?

Group handle tightening could be due to a spacer inserted under the group seal. The old seal may have been compressed and loose so a new seal and spacer was put in, making it too tight instead. For the few pounds involved, just pull it out and look. I've fixed a few classics with this issue.


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## timmyjj21 (May 10, 2015)

Dripping steam wands is a common issue. Then valve is a metal-on-metal pin valve that gets worn. You can open the valve to renew the seat, but the valve needs attacking with a file/dremel to remove the crimped retaining collar. I leave a little bit of the collar in place to crimp back over once it's fixed to prevent the valve being accidentally opened all the way when I'm use and potentially shooting steam onto your hand.


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## Grahamg (Oct 24, 2013)

Thanks for the input, will have a look at seal - solenoid needs a clean out anyway as flow had started dropping off of late (forced my hand fixing the #1 machine!).


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## Jumbo Ratty (Jan 12, 2015)

This is the official gaggia replacement. 8mm. This is what I would replace it with for peace of mind

Some others will be 8.5mm,might be cheaper, might be silicon. Take your choice

http://www.ebay.co.uk/itm/Gaggia-NG01-001-8mm-Rubber-Seal-Gasket-/201101278118?_trksid=p2054897.l4275


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## Hairy_Hogg (Jul 23, 2015)

I am worried now as just purchased this off ebay which is advertised as 8.5mm. Assumed this would be a pretty standard part









What is going to be the difference apart from the handle not taking as much rotation to tighten?


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## Jumbo Ratty (Jan 12, 2015)

Grahamg said:


> Another peculiarity is that on #1 the portafilter takes a good 1/4 turn or more to sit solidly in the group head taking no effort to engage it in 'threads' whereas #2 it's a bit of an effort getting it in and it's probably done up tight in barely more than 1/16th of a turn - if you don't do it firmly when empty and the machine warming up, the portafilter can drop out!





Hairy_Hogg said:


> I am worried now as just purchased this off ebay which is advertised as 8.5mm. Assumed this would be a pretty standard part
> 
> 
> 
> ...


I would imaging you will find it doesnt engage in the group head as well as it should.

Have a play with your portafilteer and see that when your insert it there is more of an aggressive "thread" that tapers off into a gradual "thread"

I would imagine you are only just going to get it into locking position with the danger of it falling off as the OP has suggested happens.

perhaps insert your portailter to the mentioned fraction and see how happy you would be if that was how far it would go in. , I just tried and its by the skin of its teeth.

All this is supposition, we havent had it confirmed or denied that the seal is the 8mm or the 8.5mm.

also, your 8.5mm might be made of a more spongy rubber and compress adequately


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## El carajillo (Mar 16, 2013)

As pointed out earlier in post, with thicker seal / gasket the portafilter will lock in at a lesser angle Ie 7 oclock instead of 6 oclock. It is "possible" for the portafilter to blow off if not fully locked in.


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## Grahamg (Oct 24, 2013)

I'm going to have to take back the comment on the steam wand - it's not necessarily better! Noticed this morning with a slightly larger quantity of milk that the pressure drops away after the initial 20 seconds odd blast, a pretty big change which doesn't quite properly allow for proper incorporation after stretching. A bit annoying this, starting to see why people hit the upgrade path when certain machine foibles start to grate (not an option for me for that most basic of reasons... financial!).


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## Dylan (Dec 5, 2011)

You can always consider a PID for the Classic, I believe it greatly improves steaming performance.


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## risky (May 11, 2015)

Dylan said:


> You can always consider a PID for the Classic, I believe it greatly improves steaming performance.


Really need to weigh up whether it is worth spending the money though. More than the cost of a second hand classic itself in many cases!


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## Tewdric (Apr 20, 2014)

I didn't do the OPV mod certainly but I was the second owner and #2 is certainly a well used machine. The group gasket was replaced probably 4 months before you had the machine with one supplied by Happy Donkey.


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## Grahamg (Oct 24, 2013)

It's had heavy use since I got it from you too... three espressos and one lot of milk before 7am most days! I think the Bristol water and my lack of diligence with the water filter has been a contributor too. One day, when I grow up and have a home of my own, I'll have a proper posh plumbed in machine with a filtered water supply... until then I will rinse and repeat the repairs and maintenance on my two gaggias!


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## Dylan (Dec 5, 2011)

risky said:


> Really need to weigh up whether it is worth spending the money though. More than the cost of a second hand classic itself in many cases!


Absolutely, I never did PID my classic and just decided to upgrade. But a PID is cheaper than a new machine if budget is tight.


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## Jumbo Ratty (Jan 12, 2015)

Tewdric said:


> The group gasket was replaced probably 4 months before you had the machine with one supplied by Happy Donkey.


The ones from happy donkey come with an extra .5mm spacer. Do you recall if it was installed or not?

THIS SEAL IS SUPPLIED WITH A FREE 0.5MM RUBBER SHIM, THIS IS USED TO SIT ABOVE THE SEAL TO PACK IT OUT WITH IF THERE IS EITHER A TOLERANCE ON THE HEAD OR IF THE PORTAFILTER TABS ARE A BIT WORN.

http://www.happydonkey.co.uk/hd6005.html


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