How to lube Ponte Vecchio Export piston for smoother movement

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slooowr6

#1: Post by slooowr6 »

The piston movement is not as smooth as when I first got it. I can see the lever jitters as it move up. I think the seal on the piston probably does not have enough lube on it. So I decided to open it up to lube it. Here is a quick recap of how I got it done. Be very careful the spring in the group head is STRONG make sure you are protecting your eyes.

1) I use a small screw driver to get the rubber gasket. It'll be easier to remove the gasket if you can remove the shower screen first but I don't have the tool to do that with the gasket in place, not enough space, so I prey the gasket out first. The shower screen is press fit on to the group head. You can see the lip of the screen.


2) After the screen is off.


3) Use a clamp compress the piston a little so there is no tension on the pin that holds the piston rod. Remove the c ring, make sure the clamp is secure so the spring does not jump out.

4) Slowly release the clamp now you can remove the piston.


5) The volume is pretty small for this group head.


6) There is only one water inlet in the chamber.


7) When re-insert the piston make sure the second seal counting from the bottom is properly fit into the chamber.

8 ) It's pretty hard to get the piston back in. The piston needs to go up pretty high so you can insert the pin back in. I use a clamp to compress it. There is not a lot of surface area for the clamp to fit securely. I had the clamp slip and all explode couple times. :shock:

After all is done now the piston is butter smooth again. Next step naked PF.

:D

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peacecup

#2: Post by peacecup »

Slooowr6,

Thanks for the info. and photos. I'm hoping to delay my entry into the PV group as long as possible. Did you notice any damage to the rubber? What lube did you use? Also, are you careful not to pull the lever the first time before the machine heats up? This is supposed to keep the piston well-lubed.

The PV does indeed have a small-volume group. At first I thought this was a serious limitation on espresso volume, but lately I've overcome it by grinding more coarsely and taking four pulls. Just had a very nice 2-oz. doppio Raven's Brew Organic Espresso Cantata.

The more I use the PV the more I like it,

PC
LMWDP #049
Hand-ground, hand-pulled: "hands down.."

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slooowr6 (original poster)

#3: Post by slooowr6 (original poster) »

peacecup wrote:Slooowr6,

Thanks for the info. and photos. I'm hoping to delay my entry into the PV group as long as possible. Did you notice any damage to the rubber? What lube did you use? Also, are you careful not to pull the lever the first time before the machine heats up? This is supposed to keep the piston well-lubed.
No, there is no damage on the rubber it's just a little dry. The machine is so simple the only thing needs maintainance is the rubber. After lub them I think they should last a long time. Lowes is just right around the corner of my place so I went there and got the plumber lub from Gunk, it's rated up to 400F and it's food safe. I never know that no pull untill machine heats up, thanks for the tip. I don't think you need to open it up unless you feel the piston is no longer moving smoothly. It's not hard to open the group it's just there is no good place to hold the clamp stable enough and the spring is very strong. But with enough patient it can be done.
peacecup wrote: The PV does indeed have a small-volume group. At first I thought this was a serious limitation on espresso volume, but lately I've overcome it by grinding more coarsely and taking four pulls. Just had a very nice 2-oz. doppio Raven's Brew Organic Espresso Cantata.
How long is your single pull in your four pulls sequence? The way I calibrate my process is that a single pull on my is around 14sec so when I do a double pull it's in the ~28sec range. It's very interesting that the shot time effect greatly by the type of beans I'm using. In general the bean that is more dense the shot time will be longer and I need to adjust coarser to compensate for that.


Next I'm going to get a thermometer to check the brew temp and make a bottomless PF for it.

Alex

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peacecup

#4: Post by peacecup »

How long is your single pull in your four pulls sequence? The way I calibrate my process is that a single pull on my is around 14sec so when I do a double pull it's in the ~28sec range. It's very interesting that the shot time effect greatly by the type of beans I'm using. In general the bean that is more dense the shot time will be longer and I need to adjust coarser to compensate for that.
I don't often time my shots, but just tried one - a doppio, <30 seconds total, three pulls with ~ 10 sec "Fellini" pre-infusion, so around 7-8 secs per pull. The pour was ~1.75 oz. I had backed off the grind from my previous doppio, which was a four-pull, 1.75 oz - probably ran closer to 40 sec., which I know is supposed to be too long.

The sweet spot for the double basket appears to be the three-pull, <30 sec. shot. This requires very fresh beans, however, and varies with type/roast. By the time the beans are over a week old I get less creama with the coarser three-pull grind, and need to go to the finer four-pull for more creama.

If you start to get too good at pulling doppios try your hand at the elusive solo using the single basket.

Looking forward to seeing photos of the naked PF.

PC
LMWDP #049
Hand-ground, hand-pulled: "hands down.."

slooowr6 (original poster)

#5: Post by slooowr6 (original poster) »

Update: Plumber lub is NOT a good lub to use on the piston. :( It will wear out fast under the heat in the cylinder. I'll re-lub the piston after I get the Taylor-Lub.

slooowr6 (original poster)

#6: Post by slooowr6 (original poster) »

Got the Taylor-Lube after re-lube the rings now the machine is smoooooth like butter. Here are a couple more pic to make the process clearer.

1) Pop out the screen. I used a L shape allen key.


2) After screen is out.


3) Remove the gasket.


4) Use a clamp to release the tension on the piston to remove the pins.


5) The bottom ring.


6) I use washers on the lower clamp so it can push the piston higher without the clamp hitting the rim of the cylinder.