Stirlingengineforum.com

Has anybody using oil in their engines tried Lucas gun oil? It doesn"t burn off like most oil.

I'm using Singer Sewing Machine oil. The best oil is straight synthetic oil, it's used in aviation gas turbine engines, it is low viscosity, and high temperature, will not ignite under compression as mineral oil can.
Ian S C

I was using singer sewing machine oil but switched to this. Its a lighter oil than Singer and seems slicker. I think its a synthetic. Doesn"t last forever.The inside of my power piston looks like a worn out washboard(exaggeration). Its an old pneumatic cylinder which you would think would be smoother than that . The Lucas oil makes a world of difference. It only takes a little. I just wipe the cylinder with a slightly oily rag. Don't know if its available in New Zealand.

Got some gun oil, hadn't thought of trying that, it's whats known as 303 gun oil, it's what we used on service rifles (.303 British was the calibre of our rifles until, in the late 1960s we went to 7.62 mm).
Ian S C

Ian,
What was your results with the gun oil?

I have a Stirling engine with metal pistons, interestingly the manual calls for WD-40. But after many runnings, it stopped working. The hot cap got gummed up and carboned up. After cleaning it runs great but I will take it apart reclean and use sewing oil...

So I am definitely ordering singer sewing oil...

Don't use WD-40, that and similar stuff is OK when first put on, but when the lighter liquids evaporate it leaves a thin film (this is what protects the metal from rust), maybe you'll get away with this a couple of times, then the build up just stops every thing until you strip the motor and clean it. A drop of diesel works ok, and if you are lucky the motor will run dry, because oil causes drag.
Ian S C

At the sewing shop, they have Singer and Dritz brand. The Singer oil has a slight smell - like 3 in 1 oil. The Dritz is 100% odorless.

I reassembled using the Singer oil and it runs great. I still wonder though if the odorless Dritz may be better? Any odor outgassing is evaporating oil. So I wonder if the Singer thickens over time? I must but hopefully not gummy?

Every now and then I spray a little brake cleaner fluid down the cylinder, and wash the oil, and any gummy deposits out. The main thing I try for is minimum oil.
Ian S C