# My first runner - Gamma Stirling Engine



## keys (Oct 4, 2009)

Well I've had my first runner going for a couple of weeks but just today I'm finally happy with its performance. I first used aluminum for both the cylinder and piston on the power side. It ran well for about an hour before wearing out. I replaced the piston with brass which ran well but the piston was so heavy. After reading about graphite pistons on this forum I located some and replaced the piston for the third time. My Stirling is now running better than ever.  Much better than I could have hoped for on my first runner. Finding this forum has been incredibly helpful. 

http://www.youtube.com/watch?v=5aXBl7YT32M&feature=player_profilepage#


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## Fred (Oct 4, 2009)

Hi,

looking really good! Just make sure to keep the graphite piston dry and free of grease.
Where exactly is the water-cooling jacket? Are you sure you are not also cooling the power piston/cylinder? 

Have fun,

Fred


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## rake60 (Oct 4, 2009)

Keys
If your first runner is a Gamma Stirling, you are doing VERY well in this
hobby.
Beautiful build! :bow:

Rick


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## keys (Oct 5, 2009)

Fred  said:
			
		

> Hi,
> 
> looking really good! Just make sure to keep the graphite piston dry and free of grease.
> Where exactly is the water-cooling jacket? Are you sure you are not also cooling the power piston/cylinder?
> ...



The water jacket and the cold side of the displacement cylinder are the same piece. The hot side of the displacer is bolted to the cold side and separated by a gasket.

The power cylinder is not getting directly cooled. It can get rid of a little heat through its SS hex bolts. Would it be bad to cool the power piston and cylinder. I didn't put much thought into it when building the engine.


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## keys (Oct 5, 2009)

Diymania  said:
			
		

> You may want to add a second bearing block on the other side of the flywheel, just a thought.



I think you're right. I'm not happy with the amount of play the flywheel has and the amount of force it's probably putting on the bearings.


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## keys (Oct 8, 2009)

So I found one of those laser photo tachs at a local tool store and could not resist picking one up for $29.50. Using a different torch head I was able to get my little Stirling up to 1540 rpm. From the sound in the video I'm probably maxing out around 1100 rpm.


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## Longboy (Nov 19, 2009)

...........you can cut some meat out of the flywheel though I don't think it is too much for the bearings as is.


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## keys (Dec 23, 2009)

Longboy  said:
			
		

> ...........you can cut some meat out of the flywheel though I don't think it is too much for the bearings as is.



That was going to be my next modification. The flywheel is just under 4" in diameter. I was thinking about cutting another one at about 2" in diameter. I feel that it would improve its ability to run at low speeds. It has a hard time running any slower than about 500 rpm.


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## Longboy (Dec 24, 2009)

.........You may find that going to a lighter/ smaller dia. flywheel will actually raise the stall RPM of your engine with the same heat input. Heavier flywheels tend to allow for lower RPM running. The experiment of flywheel weights and diameters is a worthwhile mod to help your knowledge base in Stirling.


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