My Jeroen Jonkman’s Stirling 60 brass Stirling engine build

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ZebDog

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Congrats on a nice looking and running engine.
Now you caught the bug you will soon be making your first i/c engine.
Thanks for sharing.
 

Technical Ted

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Just an update... I made two more, one for each of my boys. I hope they like them!

Ted

IMG_20190221_122740.jpg
 

cooksservices

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This engine looks lovely, I have built two ic engines now both four stroke. A Single cylinder 8cc and an 18cc 90 degree v twin. I have been learning the principles of the sterling engine and found this thread. I have been looking at building something of a similar size and design to your ones. The better half won’t let me run the ic engines indoors for some reason so it would be lovely to have something like this that can run almost silently indoors above the fire place for me t watch whilst she’s watching tv ☺. Are designs available for this engine? I hope your boys like their engines they are a lovely gift that i would treasure forever.
 

Ken I

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I've finished mine and after working the tight spots out it runs beautifully.

I don't like the candle - it rapidly blackens and soots up the tube - anyone know how to avoid this ?

In the meantime I'm building a Butane version using a cheap butane torch for donor parts - I'll do a post when it's finished.
 

Technical Ted

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The only time mine has had any soot whatsoever is if I have the flame too close. If the engine runs well, the flame doesn't need to be very close. I trim the wick with nail clippers as well to keep the flame small. I've used both "cheap" candles and better quality ones and the candle doesn't seem to make much difference.

Ted
 

Ken I

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Ted, Thanks - you are correct - it runs cleanly with the candle far enough away.
It was my fault trying to "force" it when the engine was still too tight - it doesn't tolerate any tight spots.
I ran mine "in" by driving the flywheel against a rubber wheel in the lathe.
It still needs to run in a little bit more as it is inconsistently self-sustaining on a small (clean) candle flame but runs fine on a slightly larger butane flame.
I'm going to complete the butane burner as an alternative / running in feature. It was almost finished when I read your reply and experimented further in any case.
I had too much interference on the test tube "O" rings and had to take the displacer cylinder back to the lathe - once I got the "fit" I was looking for I mounted the test tube in the cylinder / lathe / "O" rings (obviously radiussed end in) and parted it off using a three square diamond file. A final dress of the end with the diamond file and emery paper got me a finished test tube.
A final question - there is (by my version of Jonkman's drawings) 2.9mm clearance between the internal test tube radius and the displacer at full extension - would reducing this volume by shortening the test tube improve performance ?

P.S. mine is running with the grease still in the bearings and the piston and displacer shaft lubricated with ATF - according to Jerome these should be run dry to free up the motor ?

Regards, Ken
 
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Technical Ted

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A final question - there is (by my version of Jonkman's drawings) 2.9mm clearance between the internal test tube radius and the displacer at full extension - would reducing this volume by shortening the test tube improve performance ?

P.S. mine is running with the grease still in the bearings and the piston and displacer shaft lubricated with ATF - according to Jerome these should be run dry to free up the motor ?

Regards, Ken
Hi Ken,

Not sure about the best amount of clearance at the end. It would be easy to test by shortening your test tube. There is quite a bit of length between the inside Oring and the main body where the tube butts up to so you could play with the clearance distance and find out by adjusting the tube in and out. If you do, please report back. This is a variable I didn't play with and am interested.

I remove the grease from the bearings. They were shielded (not sealed), but I found by soaking them in brake cleaner for a few days the grease dissolved. This did seem to free them up giving the fly wheel less drag. As I've discussed before, the CI bearing was my biggest issue with all of my engines. When first attempting to get them to run I have tried a tiny bit of 10 weight Mobil spindle oil on the diffuser shaft. That has definitely helped, transforming a non-running engine into a running one. But, I also found that if I continued to oil it the power piston sooted up (from the smoking oil) and would end up binding. This required disassembly and cleaning. I ended up making several attempts at methods for making the hole in the CI bearings to make the hole perfectly concentric all the way through. Once I achieved this, my problems went away.

Ted
 

Ken I

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Here's mine parked next to my Six Shooter Elbow Engine on my bar.
20200110_151321.jpg

I gave up on the Butane burner and modified it to run on Alcohol - appropriate as it's a nice model to actually run on the bar.

I did my own version of the drawings (AutoCad *.dwg) - with a few changes and notes - if anyone's interested I'll post them under the downloads section. I don't suppose Jerone would mind.

Regards, Ken
 

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