1976 Olympia Club Rebuild - Page 3

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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wreckfish (original poster)
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#21: Post by wreckfish (original poster) »

Rebuilding the Club's group was the simplest part of the project. A clamp is a must for removing and reinstalling the piston although next time I'll try to figure out a better configuration. Positioning the clamp so it has a good footing on the pieces and so that you can access the piston rod to put the yoke and pins in took a bit of fiddling and more than a few tries.



The lip of the Club's cylinder was not entirely round, caused by years of prying out the shower screen I assume. I worked it a bit with a dowel and mallet to bring it back into shape as best I could. Of interest to me, having changed the seals on a Cremina previously, is that the Club does not have a head gasket like its brother - it does have three piston gaskets, though, unlike the Cremina's two.



The piston was the most involved part of the group rebuild. 40 years of work, and less than regular gasket changes, left a layer of baked on gasket, coffee residue and oxidation. After an initial cleaning I soaked the piston head in a citric acid solution and gently removed all the crud I could with a dremel, using brass wire brush and abrasive pad attachments. This deep clean revealed pitting in the brass, particularly around the top of the second piston. I left the face of the piston alone with the exception of a light brush with a non-scratching abrasive pad.






I found the spring configuration and the "bearing" washers at the top and bottom that provide seats for the spring at either end rather elegant in its functionality. I was never able to get the washer in the piston itself out and am not sure if it is integrated with the piston, or a separate piece.




I found a little Dow 111 on the piston rod eased installation and I assume will help in operation down the road.
The chrome on the group was in good shape except for wear around the pins and the yoke.




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wreckfish (original poster)
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#22: Post by wreckfish (original poster) »

The only thing I have in common with a $22m vintage Ferrari is the guy who did my Club's chrome...


The Club's chrome was in decent shape. The steam wand, understandably, had the most wear with more than half of the chrome gone. The portafilter, lever yoke, and piston nut and acorn cap all showed a bit of wear as well. The group was in good shape with the exception of wear around the pins and the yoke, so I decided to leave that as is.




The pieces that went for chrome.


I decided to chrome the water wand despite the fact that it was in good shape. I wanted to make sure that the wands matched. Having the group slightly different would look fine as long as the chrome on either side was consistent. That turned out to be a good decision as the new chrome finish is a little different than the original.

The finished product.

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wreckfish (original poster)
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#23: Post by wreckfish (original poster) »

Three months into the rebuild, it came time to pull out the case and the stainless trays, front plate, and grills that I had carefully packed away. At the time I thought all the stainless was in great shape and just needed a cleaning. Looking at it again, I realized that the front panel had been locked in a 40 year war with abrasive cleaning pads. There were swirls everywhere and I realized that the loss of chrome on the steam wand was likely due to scotchbrite pads as well.

A quick search on HB lead me to the idea of electropolishing and I found a company willing to do the job. Electropolishing seems to be very similar to chroming, except in the case of electropolishing a very thin layer of the stainless is being removed. I brought the stainless to the polisher and went over it piece by piece -- with the exception of a few deep scratches, he felt comfortable that he could get them looking new again...and he was right!



After polishing






The drip tray appeared to have silver solder on the corners. The electropolishing removed that -- something I was made fully aware of before the work. After I learn how to silver solder, I'll go back and clean up these joints.



I also replaced as many fasteners as I could with stainless ones. It started with the boiler bolts, but then quickly snowballed into the site glass fasteners and all the other smaller nuts and bolts around the machine. I also changed the front plate mounting bolts to stainless, replacing the chromed brass bolts whose finish was spotty.



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naked-portafilter
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#24: Post by naked-portafilter »

Great to see how this amazing machine nears to be completely refurbished. I have two '76 Club also.

Has anybody thought about using a stronger spring in the group? After my Cremina we made a pressure gauge kit also for the Club. As we played with it I was surprised that the pressure peak reached only 4 bar.



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wreckfish (original poster)
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#25: Post by wreckfish (original poster) »

That pressure gauge kit is great. Interesting results too. I had read that some folks thought the club spring was a bit weak at the end of the shot, but its curious that its peak is so low as well. Is that a temp sensor running through the boiler cap?

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wreckfish (original poster)
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#26: Post by wreckfish (original poster) »

With all the major components ready, there were just a few bits and pieces that needed finishing. I opened up the pressure gauge, cleaned the glass, and cleaned the face with a q-tip and some window cleaner. I reassembled the pressure relief valve and replaced the gasket with a new Teflon one of my making. I cleaned up all the piping and polished it. The compression fittings on two pipes needed a Teflon wrap to keep things in order. The feet were cleaned and polished as well.











I cleaned the body of the pstat but did not go so far as to break the whole thing down. Since it was working, I didn't take it apart.



I made a new wiring harness and installed a modern cable relief grommet. The new grommet required that I open up the existing hole in the frame a bit.




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vberch
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#27: Post by vberch »

This is truly a spectacular rebuild!

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naked-portafilter
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#28: Post by naked-portafilter »

wreckfish wrote:That pressure gauge kit is great. Interesting results too. I had read that some folks thought the club spring was a bit weak at the end of the shot, but its curious that its peak is so low as well. Is that a temp sensor running through the boiler cap?
Yes, it was a surprise. But excellent shots. So I don't really mind. I will make a double check with my red Club tomorrow.

The temp sensor was originally made for the cremina temp study 4:



Maybe interesting for you. I measured the group temps for the Club (with and without teflon gasket) also.

Olympia Cremina Temperature Study, Part 4

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naked-portafilter
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#29: Post by naked-portafilter »

Another '76 Club same pressure profile, excellent pour, tasty espresso:

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wreckfish (original poster)
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#30: Post by wreckfish (original poster) »

Another '76 Club same pressure profile, excellent pour, tasty espresso:
Gabor- This is really great information. Really adds a new layer of understanding to how these machines work (and the red case is awesome!). I'll check out the temp study for the Cremina as well. Thanks for sharing all this work.