La San Marco 80, converting to 85

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panchovilla

Postby panchovilla » Oct 13, 2014, 12:35 am

Hi everyone. I now have 3 LSM machines, two 85's (1 lever) and one 80 (just purchased, lever), and after thinking and thinking quite a bit about the technology and changes of the machines, I now think I understand why LSM got rid of the heat exchange (hx) system starting with the 85 series. In the 80 models, cold water goes thru the hx system, heats up, then joins up with a tiny bit of the residual hotter water sitting behind the group, then enters the group, then producing coffee. If you do not have a constant flow of cold water entering the hx, you cannot produce many coffees, even if your boiler is full. So if you fill the boiler, then turn off your water line, then you will make a drink or two, but then no more coffee since the hx is no longer receiving water, thus no more water to the group.

Another problem I see with the 80's is that water in the boiler is never fully being replenished, drained, unless one is continually draining the boiler, either by making a lot of tea drinks or americanos or steaming a lot of milk. The water for the group/coffee is coming 99% from the cold water that went thru the hx from the incoming water line and 1% from what was in the tupe/pipe that sits inside the boiler. In my 85 Leva, I see that LSM got rid of the hx tube, and hence the top little hole where water enters to the back of the group, so LSM must have obviously thought that this was a more efficient way to continuously produce .9 Bar pressure water for coffee. Water heats up, then exits the boiler thru the big tube/pipe, to the group, then we get coffee. On my 80, my idea is to a-plug up the hx tube holes in the back of the boiler, b-plug up the small holes of water entering the group and to c-make a hole on the big pipe that sits in the boiler, thus allowing water to enter the group, and hence convert my machine into an 85. This should work fine. Am I thinking straight, or am I missing something here?
Putting disc brakes on a drum brake system,
Gerry

phillip canuck

Postby phillip canuck » Oct 13, 2014, 11:15 am

Oh my goodness. If you haven't seen this video, then watch it before deciding about "converting" your LSM 80.



-phillip

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homeburrero
Team HB

Postby homeburrero » Oct 13, 2014, 12:15 pm

phillip canuck wrote:Oh my goodness. If you haven't seen this video, then watch it before deciding about "converting" your LSM 80.

+1

I think dippers (as opposed to HX) are popular on lever machines for various reasons, but they are certainly not better. The HX gives you more functionality with more flushing/waiting hassle, and is used on some modern high end lever machines (e.g., Victoria Arduino Athena.) Hopefully Doug's video will convince you that your model 80 is a marvel of well designed and highly functional mechanical engineering that many folks would treasure - hacking it into a dipper seems a travesty. Plus it may not work that well because the 80 was designed and tuned for thermal stability as an HX. If you want a dipper I bet you could sell your model 80 here on HB and get more than enough money to buy one.

panchovilla wrote:If you do not have a constant flow of cold water entering the hx, you cannot produce many coffees, even if your boiler is full. So if you fill the boiler, then turn off your water line, then you will make a drink or two, but then no more coffee since the hx is no longer receiving water, thus no more water to the group.

Maybe your whole problem with the machine is in not using the water supply correctly. You want pressure in the HX at all times. My understanding is that the water line should always be on, and you have a separate valve for manually filling the boiler. (See Doug's video.)
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

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cuppajoe

Postby cuppajoe » Oct 13, 2014, 1:08 pm

Three at once? Wherever did you find them in SoCal?

Have a buddy restoring a '70 Torino for his daughter in law and just got through with the disc conversion. It will be a daily driver and is rather unassuming, so the conversion made sense. Have another friend with an all original '55 Corvette in the garage. I would want to be more than arms length away from him before suggesting he do the same.

Think there are plenty of folks out there who would love to have the 80 just as it is, would make a wonderful show piece in a cafe. Heck, if I could justify it for making two caps a day I'd try and snag it off you just to keep it from going under the knife...

PS - Yes, as Mr Burrero mentioned, water pressure is supposed to be supplied to plumbed-in machines at all times(during use), either with line pressure or an external pump and reservoir. Lots of HX info on this site.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits