I am renewing knowledge of this very interesting engine...
Guys your really need to look into all the information here:
https://www.bourkeengineprojectllc.com/
I ran into a guy with photo copies of the scraped together book by Mr. Bourke about the engine... it was a bit of a mess.
It has been cleaned up and is much better form now.
Now if I was struck rich I have a second dream to build, and this engine just might be number one ahead of Gasoline vapor.
Rich