Recently I got a NS Oscar second hand. I tried to find details about this machine, proper specs and a decent user manual but, to my surprise, the information is surprisingly poor for a name like Nuova Simonelli. I'm sorry my italian friends, but you really don't know how to write a user manual...

1. How good is the espresso made with Oscar comparing with an E61 machine? Does the E61 preinfusion make a huge difference?
2. NS has its own way to keep the system up to temp. Is it better than others?
3. How good are the factory filters, shower screens, steam tips comparing with the upgrades (big difference, some difference, night and day)? Does make a difference to buy them for everyday use? What options are there?
4. How reliable is Oscar? What kind of maintenance should I do? My local NS dealer/repair centre said descaling is not a realistic option. Also I saw in some videos the boiler in some machines looks disgusting, corroded. Why? How can I prevent that?

I will appreciate any detail and story about the Oscar!

Thank you!

daopi wrote:1. How good is the espresso made with Oscar comparing with an E61 machine? Does the E61 preinfusion make a huge difference?
2. NS has its own way to keep the system up to temp. Is it better than others?
3. How good are the factory filters, shower screens, steam tips comparing with the upgrades (big difference, some difference, night and day)? Does make a difference to buy them for everyday use? What options are there?
4. How reliable is Oscar? What kind of maintenance should I do? My local NS dealer/repair centre said descaling is not a realistic option. Also I saw in some videos the tank in some machines looks disgusting, corroded. Why? How can I prevent that?

I assume you refer to the original Oscar and not the current version. I have no experience with Oscar II.

1. I loved my Oscar and the espresso it made. It was very easy to set up, use, clean, and maintain. I used it without modification for a few years before getting the urge to try a pressure control mod I read about on HB. So I added a dimmer switch to the pump power line to control brew pressure, with no significant change in the cup.

When we downsized and moved from our house to a condo apartment, I was in the mood for a bright and shiny new machine. So I bought an e61 ECM to see what the fuss was about, and it makes truly great espresso. The e61 will let you get more out of subtle and sophisticated light roasts, if that's your preference. But I prefer a classic blend, and Oscar's brew was just about as tasty as the ECM's. And to be honest, I'm still not 100% thrilled with the mechanics of using an e61. Oscar was so easy to use that it spoiled me - I'm used to the e61 after 18 months of daily use, but it takes more movement and effort to pull a shot than Oscar did.

Preinfusion does give me fantastic consistency and freedom from gushers. But I had very little problem with that from Oscar, and I changed my dosing method after getting the ECM to grinding into a pitcher and shaking it before putting it in the basket.

2. The grouphead temperature is maintained by a thermosiphon system, and boiler temp / pressure stability is determined by a high quality pressurestat. Neither of these is unique, and both work well. The group is not directly attached to the boiler, but that's also not unique to Oscar.

3. The fittings are all solid and of good quality. I bought the stock NS diffuser and screen when I cleaned up my machine and was very happy with them. I used a silicone group gasket, which is a good idea on any machine for which it's available. The standard rubber ones harden and become problematic at some point in the second year for most home users. So if you stick with the stock gasket, I'd replace it every year or whenever it starts to feel like it's losing resiliency when you lock in the PF.

I did replace the stock steam tip with a 4 hole La Marzocco tip from Espressoparts. Oscar's a steam monster that foams like a professional machine with this simple addition, although it was fine with the stock tip. It's just faster with the added area of the 4 large holes, and the boiler can easily keep up with it.

Older Oscars often have cracked boiler insulation that may even have fallen off inside the machine. This looks bad but isn't a serious problem. Mine was OK, but the simple solution for this if it happens is to pull off the old stuff and just wrap the boiler with exhaust system heat insulating tape (available from Amazon and any good performance auto parts supplier).

4. The original Oscar is a workhorse - it's solid and reliable, and I'd buy another today with no hesitation at all. I'm not clear on what you mean by "the tank" - the water reservoir is plastic. If you're looking at the boiler, you're probably seeing the insulation problem mentioned in 3 or deposits from leaking water. If there's any sign of a leak at any fitting or interface, take it apart and fix it properly - don't just try to overtighten it or seal it by applying glop to the outside.

It's a rare espresso machine that never has any condensation or leaking water inside, and that's what causes rust and other ugly stuff on the frame etc. If your machine is already affected, the best fix is to strip it down, remove the rust with your method of choice (sanding, media blasting etc), and either paint the frame with a good coating like POR-15 or have it powder coated. Most of this yuck is purely cosmetic, but I agree that it's distressing to see. POR-15 can be painted right over rust to stop its progression and improve appearance - but this doesn't look as good or last as long as proper cleanup and prep before painting.

One thing we found with the office Oscar 1 was that grouphead gaskets that are claimed to be for the Oscar are not all actually any good - we suffered with either gushers or choking for years, even with replacement the gaskets every few months until I had the bright idea to *ask*. NS gave the the correct part number, and I ordered those - they are conical, (not flat, as was in the machine when I first started paying attention, and what I had been getting as replacements) and just work, no more issues here...

From NS: "The gasket you need is 02280020.V 7mm."

Thank you guys for detailed response!

Anyone knows the official basket capacity of Nuova Simonelli double and single ones? I assume Oscar uses the regular commercial baskets...

Thanks!

About 2, I didn't like the rising temperature shots. I installed same restrictors Musica and Oscar II have:

Nuova Simonelli Oscar restoration

About 1, there should be a flow restrictor (around 1mm) right after the retention valve before the HX inlet. It delays the pressure ramp rise about 8-10 seconds. I did played without it and it was more difficult to tame the group. So I let it there (I think I even put a 0,9mm restrictor in one of the two machines I restored).

Some months ago this second machine I restored and painted red came back to me and I found another owner for it. I pulled some shots and they where great. I added a IMS shower screen and I was using the tapered double filter from Espresso Parts. But, for me, the thermosyphon restrictors are the most important mod.