Hi All,.... it has been a busy couple of weeks since I got my 1975 Cremina.... wouldn't you know work got busy right when I started my rebuild project.... Anyway, I have been working on the rebuild in 15-30 minute sessions, and I have cleaned all the parts and gotten the boiler element bead blasted (now it looks brand new!). All I need now is a clear weekend to re-assemble and fire her up!

Here is a picture of the grouphead after I cleaned it a little. I noticed that there are some grooves in the wall of the grouphead, and I am wondering if any of you other rebuilder/refurbisher's of Cremina's have seen this in your projects? The piston did have a gank mark at the top, like where someone pushed a screwdriver through the water inlet hole. I think this might have scored the grouphead wall. The groove is only a thousandth or two deep. I have sanded off the gank mark on top of the piston so it won't muck up the cylinder wall again.


I am thinking of porting/polishing these grooves out by using a motorcycle mechanic friend of mine's cylinder polishing stones, that are on a spring-loaded "tripod" jig. You just put this thing on a drill, and run it up and down the cylinder a few times. The springs apply pressure and adjust to whatever size cylinder you have. The stones are very fine grit, and it is new (never seen a motor). I know that I don't want to port out the grouphead to a bigger size, I am just thinking of trying to get out the scar. But maybe this is overkill, and the new seals I have will not even notice the grooves. Thanks for any input in advance.

PS. I saw or read about the pair of two little channel grooves on the piston, that are for vaccuum reduction.... and I think that is where the shallower markings are from. But the bigger, deeper mark, that I am looking at, definitely came from something else like the gank in the top of the piston. Anyway, I might just re-assemble the machine and see if I have any pressure problems when I pull the lever, i.e. water bypass. If I do have an issue, then for sure I will polish with the stones. Thanks again.

Well, it has been a while and now here are some pictures of the "fresh" grouphead. The tripod tool worked great! Even though I am just now posting the pictures, the Cremina has been working since around the 15th of November. Awesome Machine!! I am using it more than my Vetrano!

A couple more 'After' pics:

That turned out really nice! good work. Do you have a photo of the machine that did the job?

I imagine this is the honing tool he is talking about: http://www.tooltopia.com/kd-tools-2833.aspx You just have to be careful not to lift the stones too high in the cylinder when you are making your passes as you don't want the spring loaded arms popping out of the hole when the drill is running. The stones will break easily if they hit anything.

John B.'s link to that tool is just like the one I used. Here's a picture anyway. The one I borrowed isn't quite as cool as the one at toolopia... Theirs has adjustability for spring tension. Also you are correct that you have to be careful not to pull it out past the lip of the cylinder. I just went slow at first, used some cutting oil, and got the hang of what the tool was doing. It is not like it is cutting large amounts of material. I used a medium speed with a hand held variable speed drill. It took about 4 mini sessions of dressing/honing, cleaning out the oil and checking progress to see where I was. It was pretty satisfying to work out those grooves.

Cheers! Happy New Year!!