Last week, I acquired this Conti Prestina in need of a total restoration:



I'll get around to taking some decent photos, for now all I have is this picture from the ad and some blurry phone pics.

The good news:

- it seems to be in better shape than the above picture would indicate. Sure, it needs a total teardown, but it seems to be unmolested and free of any dents, bent/missing parts or dodgy modifications.
- the case bolts and water and steam valves came out without issues, so I'm cautiously optimistic about loosening the boiler bolts (I'll probably eat those words in a few weeks).
- We've restored quite a bit of classic cars in the shop, so I have access to sandblasting, painting, powercoating equipment and all the tools I could possibly need.


The bad news:

- I don't know anything about espresso machines. Seriously.
- it needs chroming. My chrome guy's lead time is around 1 month so this whole ordeal is going to take some time. A quick glance suggests only the lever and group filter holder need chroming, possibly the drip tray. The rest appears to be polished stainless. Is this correct? How about the water and steam wand?

For now, I'd like to start by ordering just about every seal this machine will need. I understand Conti still make this group for the PMS Evolution. Is it smart to replace the spring? I can visually assess condition, but have no idea what its proper relaxed height should be. How do I go about getting all the other small seals and fittings I'm likely to need? I am in Europe, so that should hopefully simplify matters a bit with regards to metric sizing. What about boiler gaskets?

In terms of electrics, everything I've read so far seems to indicate it's smart to modernize (fuses, pstat), which I intend to do. An on/off switch and some indicator lights would be nice as well. While I'm at it, perhaps a PID (if I'm doing away with the original electrics anyway, I might as well go all in).

I found Orphan Espresso's website, but sadly the parts manual hosted there seems to be broken. Can anyone tell me where I might find a copy of the relevant diagrams?

Other than that, I'm sure I'll have a million more questions but I simply don't know enough about espresso machines to know what they are at this point. A few that come to mind: what sort of boiler insulation should I use? Should I replace the emergency pressure relief valve, if so, with a more modern model? The sightglass is cloudy and has no indicator line, where can I find another one?

Somewhat related: I'd like to get a period correct grinder with a matching design. Can anyone suggest a good 1970-1985 Conti model?

Here are some quick and dirty pictures of a quick teardown (I couldn't resist):

Hi Adrian, and welcome to Home-Barista.

The Prestina's a great machine and well worth restoring. Please use the Search engine here. It would find this for you right away.

Conti Prestina Espresso Machine Restoration 101 (Completed and Indexed)

I've also had very good results adding a PID.

Why PID a Conti Prestina?

@drgary: I already found both of those threads and am reading them piece by piece (it's quite a bit of reading!).

In fact they're how I ended up here, one of the first Google hits for "Conti Prestina". I suppose I mainly opened this thread - including the annoying amount of questions - aimed at European members. In terms of parts availability, I suspect it should be both easier and cheaper to stay within the EU.

OK, I'll get off my high horse!

Your machine looks very similar to mine when I started. Yours is more complete because you have the drip tray and grate and the Conti badge on the front panel.

The boiler gasket will be hard to find. You may need to fabricate it. I hope your boiler bolts are in good shape but am not optimistic from my experience. I tried "stainless" bolts and finally went to marine-grade stainless. Yes, the panels are polished stainless steel. I hope yours aren't scratched. Getting scratches out is a chore and unless you have a large buffer, you spend hours not getting the result you want. I like the brushed look on mine. I think replacing the spring is worthwhile. They are available and are inexpensive. You won't have to scratch your head wondering whether your old spring is performing to factory spec. The steam and water taps tend to turn. I finally solved that by using a thread locker. Some people have used JBWeld, but that's too permanent. You've probably read that I made a lot of the gaskets myself.

The boiler bolts will probably be the single most challenging thing about this whole ordeal, I agree (but remain cautiously optimistic). I've given them a good soak in penetrating oil already during my quick inspection disassembly. Regarding the boiler gaskets, I've already found some useful tips regarding what gasket material to use. The stainless of the panels is in reasonably good shape and the chromer I use offers a polishing service that should work wonders.

For all the little o-rings etc, I'll probably buy a large assortment from a hydraulics shop, I suspect viton should work just fine.

In terms of the grouphead, I've opened a corporate account with Conti Spare Parts and am amazed at the very reasonable parts prices. I've contacted them for a list of Benelux resellers, but ordering straight from Conti seems perfectly doable.

The biggest question marks for me right now are:

- where to source certain oddball gaskets in the EU for stuff like for instance the U-grooved fill valve gasket, etc
- if I consider PID control, I'd like to opt for an Arduino or Raspberry Pi based setup. There are several projects I've found, but I'd like to go with one that has gotten some traction amongst multiple users and is somewhat proven so I don't have to try (and possibly fail) to reinvent the wheel.
- auto-fill: worthwile addition and if so, is there a preferred set of components to do this?

Most of those bullet points are not really Prestina specific, looks like I have quite a bit of research ahead of me.

I suppose your enormous thread being the first thing I found, was a bit of a double edged sword, lots of info, but lots of potential problems as well.

That being said, being in Europe should simplify some things by the looks of it. I'm certainly less intimidated than I was a day ago.

You look very well prepared to restore yours quickly. As you can see by my megathread I was learning every step of the way. The good news is you'll have a very fine and collectible commercial lever. I'm looking forward to watching this thread unfold.

Today I had a few hours to disassemble the Prestina. Casualties so far: two snapped boiler bolts, luckily they both are in unthreaded holes, easily drilled out. I still have to tackle the threaded studs though, so I'm sure some problems will arise.

Some pictures:










Also hit two snags:

1) as expected the group is firmly stuck to the boiler lid. Current strategy: picking away at the very thick gasket which should give me a good 3mm of clearance between group and boiler lid. Once all gasket material has been removed, I should be able to give the group a good whack with a mallet towards the boiler, hoping to loosen the group. I opted for this strategy because it avoids applying massive amounts of lateral force to the grouphead studs. I am open to other ideas though.



2) I managed to loosen the top valve body, however it just keeps turning without threading out. I'm hoping that's because it's a fitting held in place with a nut inside the boiler? Anyone that can tell me whether or not this is the case?



That's about it for today. I placed an order of parts with Conti which should process somewhere next week. In the meantime, I'm still selecting components for PID control and considering an autofill circuit.

For the group stuck to the boiler, Doug Garrott suggested I use a mallet. That immediately got it off without breaking the studs. However if you are concerned about the studs you could try gripping and turning them out after applying penetrating oil. To your question of whether the valve body turns because there's a nut holding it in place, good guess!



Do you have the exploded parts diagrams? If not PM me and I'll send them to you.

With regards to the nut on the valve body, that's a load of my mind! I did try tapping the group with a mallet but so far no luck. I think some additional play obtained by removing gasket material should do the trick.

Hopefully I'll have some time to continue tomorrow.

Concerning the diagrams, someone already sent them to me, thanks for offering.

If you don't know how to already a good machine shop should be able to tell you how to get a good grip on those studs and get them out. As an amateur after a good soaking in penetrating oil I would consider perhaps attaching two nuts and gripping the inner one to turn it out. Or, you could grip them with vise grip pliers and maybe heat them too. Gasket material can be burned away with a low heat torch and then chipped out. Perhaps prying with the blade of a screwdriver or tapping it into the gasket and prying could loosen it too.