Does anyone here have any tips RE: pulling, dosing, temp surfing for a new owner of a Kim Express? This machine won't normally be used for steaming milk, but if you use a machine like this for steaming, what's your routine?

I've studied all four of the videos online (two by OE and two by Rochitos), as well as the Kim Express threads on the lever forum and have some basic concepts down:

1. Turn off the heating element when the pressure release valve starts to hiss. [Noise control option: open steam valve till hissing stops, then close it.]
2. Don't overdose (max w/ the OEM basket seems to be under 16g.)
3. Hold lever down for preinfusion.
4. Empty the boiler after each use.

This will be used by a friend of mine. As far as temp management, I'm going to recommend that he get a temp strip from OE to help him fine tune his thermal routine and make things more repeatable.

Thanks in advance for any advice.

[I'm also curious if anyone ever discovered a readily-available compatible portafilter, one that can be chopped for a bottomless option with deeper baskets.]

Here are some pics the machine:









While I've seem some pics of piston faces stamped with the date of manufacture, in this case the date is indicated on the exterior housing. It was manufactured in 1969.

Here's another question. [Doug or Farmroast or Dr. Gary out there?] Anyone have a source for replacement springs for a boiler pressure release valve?

I put an OE steam wand boiler pressure gauge on this machine and the boiler pressure gauge reading at steady state is about 0.65 bars. Other Kim Express threads report steady-state boiler pressure in the 0.8 - 1.0 bar range. When I took the valve apart, the spring felt tired, if you know what I mean. [I don't have the spring in front of me but it is about 1/2" long and 1/4" in diameter and is used to seat the ball bearing that regulates boiler pressure.]

The dispersion screen spring clip is also ready for retirement. It looks like this takes a 49 mm portafilter spring clip or similar. If you know for sure what size that is please let me know.

Thanks.

(Nice easy access to the piston spring and piston, which are in perfect condition. Also, the Kim Express uses the same portafiler and lever handles as the early Olympia Express machines. But the Kim lever arm is about 25% longer than the Oly.)

Thanks Gary. It looks like Marcio has a source for piston springs. In this case, I'm just looking for the tiny spring inside the hiss valve located in the lid assembly at the top of the boiler. I'm sure it's a metric spec, but I don't have the spring in front of me-it's roughly 1/2" long by 1/4" in diameter. Pretty generic spring, except for the diameter. There's a nicely machined brass fitting with a flange on top that nests inside the spring; the bottom has a pyramid cone-shaped recession that the ball bearing seats in.

(It's actually about the size of the spring used on the bottom of the burr axel of a Peugeot hand grinder. I'll dig one of those up and if it fits and, if so, what that does to the boiler pressure.)

Besides sourcing a new spring, you can look into changing the timing of the release valve. The further you screw it in, the more pressure get build up.
In terms of a routine I don't agree with the necessity to dose below 16g. I can get good results with anything between 16-20g (for a double). It is propably the easiest to stick to letting the boiler come to full pressure, shut off and then make sure that you don't wait too long with the shot or you loose the pressure needed to fill the chamber. I think I have a video somewhere (which will differ a bit from rochitos) so you can see how I pump for preinfusion and how quickly the lever rises. I never use it to steam milk so I can't speak to that.
It's definatly a capable machine but the learning curve was steaper for me than with my pavoni and peppina. It delivers a unique and enjoyable shot though.

Thank you, Peppi.

We're getting 0.65 bars with the release valve screwed all the way down. I've taken the valve apart and there is no additional adjustment-unless we hack it somehow, which wouldn't be too hard to do. But a new spring would solve the problem, and last for decades.

It's great to know that there is some adjustment in the pressure release valve when it is working as intended. That makes sense. Do you happen to know what your machine is set to?

We'll take another look at the dosing. The dispersion screen sits pretty deep down in the basket, 3-4mm, and I'm assuming you want some additional clearance below that. My first dose was 17g and it made a mess of the dispersion screen (but the shot tasted pretty good). I'll do a coin test to see for sure where we're at when the puck is dry.

Is there a way to add a thin washer or two at one end of the spring to increase the compression? If there is not a secondary safety device (that is, if this is the one pressure release that acts as the safety as well as the temperature control), proceed with great caution!).

That's exactly the hack that occurred to me. Sourcing the right washer is probably as much work as sourcing the right spring. I have a lot of odd parts in my shed, but not so many metric washers.

I pulled a spring that is 20mm x 10mm off of a coffee grinder; the wire diameter is 1.1mm. Will check that against the compression spring in the Kim pressure regulation valve later today.

Since there is no additional pressure relief on the machine, we'll have a known good pressure gauge on the steam wand if we change anything in the existing setup. If the valve isn't hissing a 0.9 bars, we'll shut it down.

Good news. It sounds like the boiler pressure readings are up this morning. After we broke the machine down yesterday and reassembled it, we never fired it back up. My friend reports that the boiler pressure is running over 1.0 bar today, so we may have fixed something. I told him to dial the valve back inside the 0.8-1.0 range. (Lower might be better if he's not steaming milk?)

Good to hear you are making progress. The spring must be old if that is all the pressure you are getting with the valve all the way down. I get good pressure with about half a centimeter to go down. I unfortunatly don't have a pressure gauge so I can't tell you my pressure.
I do have a wet puck when I use 18g of coffee or more but as long as i tastes good... plus it seems to be wet either way and I find that I have to grind rather fine as is. I can't get shots with a very heavy body but it shines in other parts. I haven't played around much with the different parameters lately but if you want to try a softer preinfusion, learn the point just before the release valve really opens, then pull down the lever, keep it there for a bit, let it come up till you feel the resistance and bring it back down, let it rise till the first drops and pull it down a third time and let it go for the shot. The temp will be lower as well so you should match this to your coffee. Generally the design is quite temp stable.
Good luck on finding a new spring. I would consider contacting Francesco (http://www.francescoceccarelli.eu/)
He got me the seals for this machine. He might have a spring for you.