First stirling build ... won't run.

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Nut

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I've just built my first Stirling based off the Grizzly H8101 plans. But I cannot get it to run. It spins smoothly and quietly. With conrods disconnected it spins for about 3 to 5 seconds. Pistons are a good fit. If I apply heat and spin it with the power piston disconnected that piston jumps up and down. The out of phase timing is correct. The power piston is graphite in an aluminium bore. The displacer piston is hollow/capped aluminium in a steel bore with 1mm free space. Am I battling friction? If so, I'm at a loss as to how to get it any better. I do wonder if I have bought myself undone in 2 places. The first is I have used home cast aluminium that has tiny pin holes, these are bubbles and not through holes but I wondered if it could be effecting internal pressure. The second is that much of my crank setup is steel on steel. The displacer piston shaft and flywheel shafts are running in brass bushes but everything else is steel. Again I wonder if they are minutely galling and/or just adding to much weight to the whole system. Any pointers that could be offered would be very much appreciated. Thanks Nut.
 
It spins smoothly and quietly. With conrods disconnected it spins for about 3 to 5 seconds.
If you are talking about the flywheel, then 3 to 5 seconds is too little. For my engine the flywheel must rotate for at least 35 seconds.

. Pistons are a good fit. If I apply heat and spin it with the power piston disconnected that piston jumps up and down.
That reflects the good fit of the piston and cylinder, as well as the airtightness of the engine .
You are very close to making the engine work, trying to reduce friction, or not smoothness between parts.
 
If you are talking about the flywheel, then 3 to 5 seconds is too little. For my engine the flywheel must rotate for at least 35 seconds.


That reflects the good fit of the piston and cylinder, as well as the airtightness of the engine .
You are very close to making the engine work, trying to reduce friction, or not smoothness between parts.
Thank you. I'll concentrate on the flywheel/crank setup as it does not spin anywhere near as long as you expect.
 
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