Not having built a vacuum engine I can not comment but having built some hot air engines using cast iron pistons running in steel bores and piston rods running in cast iron bushes one thing I have learned is that friction is a killer and getting a good seal on the power piston and displacer rod...
try a light oiling with very thin oil / crc . wd40 on any parts that open to atmosphere ie power piston . displaver guide . my stirling wont run without a bit of very thin oil on the power piston and displacer piston rod .
all joints are spigot and socket and, i use teflon plumbers tape as a...
Most Rods fail under tension and its on the exhaust stroke as there is no cushioning effect as per the compression stroke and that piston wants to just keep going straight ahead . The force generated by a piston hitting TDC at 1,000 RPM is 50 times its initial weight when the engine is not...
I concur with the comments about fusion 360 . its free and plenty of tutorials on You Tube
Designing a two stroke similar to a ships diesel with crosshead piston etc and its facinating to be able to animate it and see all the bits working and where any conflics might be.
I would look at what is available of the shelf ie 4 stroke weed wacker pistons rods valves and even maybe cylinder heads etc
6x35cc = 210 cc should give you about 4 hp
Something I always did after honing bores is to boil the part in hot soapy water
( after Solvent wash ) ,
later we bought a purpose built parts washer that hot washed the cylinders ( Some 400 Kg )
This opens up the pores in the metal and release the grit from hones or laps
Proof is wiping...
labrynth piston compressors are common in gas process industry see below http://www.jsw.co.jp/en/products/reciprocating_compressor/labyrinth_piston.html
Brian
I think you have made a basic mistake with your design
The Hot air engine works on the expansion and contraction of gas due to heating and cooling
I Think You have the Cooling Fins on the wrong side of the Plate which has the port going to the power pistons.
I use Berocca Viatmin Tubes...
Brian
I used to help build and sell CNG compressors 3-4 stage up to 750 hp 3600 psig discharge. I remember one company that spent millions of dollars developing a small 4 cylinder 4 stage compressor using scotch yoke system and ceramic valves for a home refueling . We ended up with a few...
Hi Terry , coming up for the 4th anniversary of my CABGx3.
Just bought a motorbike . never felt better, but I will admit that recovery took a while.
Good luck and welcome to the Zipper Club ..
Ralph