This engine worked exactly as I hoped. It worked prefect right out of the box, looks great, and is just a fun demo of the Stirling technology.
Great product, use it this year to demonstrate energy conversions, engineering design, and students were amazed to see it in action. Stirling engines are not practical in real world applications and shouldn't be run excessively
Do yourself a favor and follow the manufacturer directions and never use liquid based lubricants on it. Instead do what they say - dust the mechanical points with the tiniest amount of graphite powder
The quality is better than I expected. My two teenaged sons, both became completely focused when I showed them, and then a big smile came across their faces. Great deal! Soild construction. No cons.