1976 La San Marco Tipo 75 two group - Page 2

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truemagellen

#11: Post by truemagellen »

IamOiman wrote:You're right, normally I've been using a rubber oil strap wrench and a firm tug with no issues for the other two groups I've disasssembled. The pistons should not be as stuck as this troublesome one, and for ones in the future that also may fight me I can see what can be sourced around here or if I go and just try to make my own.

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If you need to borrow please let me know


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IamOiman (original poster)
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#12: Post by IamOiman (original poster) »

I'll keep that in mind, thanks for the offer 8) . That tool looks like it will work with my angled slots too on my piston faces.

I figured out why there was some play in one of the groups (the older looking one that was originally on the left), and that is because the piston rod is loose, and the internal pin was failing. It was taken out in two pieces. I also had to clean the threads from the metal glitter that was created from the pin that completely failed.



In the meanwhile I did my degreasing and cleaning regime for the valves and relevant group parts. I had to do multiple rounds in the tumbler due to the large number of parts I was cleaning. Some parts are plated so they will not give as much shine. There's various other parts in the mix like the group and flange nuts, a few body panel screws, the heating element nuts, etc.




The manometer actually has a more recent date than the machine, 5 July 1977. I wonder if the original one failed. The bezel was also missing one of two tiny screws that secure the bezel to the manometer.
-Ryan
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pizzaman383
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#13: Post by pizzaman383 »

It appears that the lever forks are fairly different between the two groups. Is the smaller pivot hole in a different location with respect to the large hole? It looks in the picture that one might overlap more.
Curtis
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IamOiman (original poster)
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#14: Post by IamOiman (original poster) »

No, the biggest difference in shape are the pointy ends of the forks which should not affect anything. I was able to switch the fork pins between them without issue.



I investigated the frame a little more too because I have seen on other San Marco machines the group/flange studs are not metric. Looking into it the studs are actually just a regular M8 x 1.25, and I was easily able to thread a bolt onto an original nut and thread an M8 nut onto an original stud. The studs screw into the frame and can come out, and so far I have removed two out of eight. I measured on my LSM 6X and that one does have an SAE thread for the group studs, 5/16" 18 TPI





The lower skirt pieces come off via six screws, two on each front corner and one on each rear corner. The skirt is made of two pieces, one covering the front and sides and the other piece covers the rear and also secures the little foot frame pieces. The two 'feet' pieces I am referring to simply slip on over two beams at the bottom of the frame, and are only secured by the four aluminum feet I took off earlier. However, there was some rust from the frame that fought me while slipping the pieces off.




-Ryan
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IamOiman (original poster)
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#15: Post by IamOiman (original poster) »

I had to wait for the arrival of a big (and I mean BIG) 35mm wrench to take off the dipper tubes. The design of the boiler did not allow me to fit my adjustable wrench and be able to exert enough torque to loosening the big 3/4" BSP dipper tube threads. With the 35mm wrench I could easily fit the tool and knock both tubes loose with my deadblow hammer. I am able to lock the outer fitting onto my vise which allowed me to exert the necessary force. The dipper tubes are designed differently from the modern San Marco dipper, with female threads for the old one instead of a male thread for the modern tubes. You can also see the LSM 75 tubes are a little longer than the LSM 6X, shown on the left.





With all the pieces apart I spent most of today cleaning them and taking off the nasty old gaskets. I had to take picks and gently poke off the gasket residue, and with some wire wheeling, citric acid baths, and magnetic tumbler they are all cleaned up.




The boiler is cleaned up to my satisfaction. A nasty gasket was taken out of the boiler lid and I am still cleaning that up.

-Ryan
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truemagellen

#16: Post by truemagellen »

Looks like LSM since expanded the size of the group flange internal cavity.
. Not sure if this helps with temp stability or not to have almost like a quasi brew boiler of slightly lower temp water (water staging area)? This was my theory atleast.

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IamOiman (original poster)
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#17: Post by IamOiman (original poster) »

I think they are pretty similar in size. See a brand new flange from Nuova Ricambi and the ones from the plated LSM 6X flange on the left and a LSM 75 flange on the right



I forgot to show that the frame is fully stripped now with the group studs taken off. It does have some rust so I am still deciding what to do with it.
-Ryan
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truemagellen

#18: Post by truemagellen »

Do u use the enzyme rust remover? Is love to use a laser based one

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#19: Post by IamOiman (original poster) »

If I strip the frame or other parts I media blast it with my Metal Guy's blaster
-Ryan
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#20: Post by IamOiman (original poster) »

I took apart the original pstat. Unfortunately this older style of sirai does not have available spares from the big parts sellers, but it is certainly a cool piece. It is designed just like modern Sirais but with the diffrent membrane. I will be using a modern Sirai 20A for now but I will see if in the future I can get a spare membrane kit made for the original.







The hot cup tray valve was taken apart after my metal guy showed me you can clamp a socket in the vise to exert the leverage needed. Nifty stuff. It's the same design in terms of seals used in modern San Marco machines.



The body panels were washed up. I will keep them original, but I did need to bend back one of the side brackets and panels that appears to have been struck by something in the past. I used my vise to get the worst of it out. I also got rid of the crud on the lower panels using green scotch brite to pretty good effect. The feet are still at my metal guy's place since they are getting media blasted.






The boiler and pipes were cleaned up on the wire wheel. The hot water pipe fitting will need some extra sealant tape, or perhaps even a repair as it wobbles a bit.


-Ryan
Using a spice grinder violates the Geneva Convention
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