Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Hero, I changed the cutaway pic title to reflect that it was from early 1978 manual. Earlier John Griffin letters show that Solar Engines must not have had too many Owners Manuals  ready to ship with the engines, and thus Griffin was promising to send the Owners Manual latter.
One important point of interest that may contribute to solving the mystery of the Thermal Energy engines is look closely at the above cut-away. It shows a very early engine with a different power piston and a “knuckle” for a wrist pin. These two features were not present on latter 1977 engines , thus maybe cutaway is from early Thermal Energy version closely copied (not exact) from Davies-Charlton.
Also, I found 1977 advertising brochure promising the  Sun motor to be introduced in Summer 1978.
Pic Circa 1977-78 “Tomorrow’s Promise”