Hello Frank, Bruce and Matt:
Some information re the TL OS/ST .40 Stunt engine:
Built 1977
Cautioned not to remove the head and/or the backplate.
There appears to be an aluminum piston with one conventual ring.
Four square exhaust ports are seen in the exhaust stack.
The cyinder was honed to make it straqight.
Use an 10-6 Wide prop with 25% castor oil fuel.
What modifictrions do you think were made to make this engine a first flip starter?
Honing of he cylinder?
Custom ring made to FIT the cylinder? Did the two together provide the outstanding compression? It leads me to think that a cylinder must be honed prior to fitting a ring! I have engines rebuilt by "experts" that had no-inadequate compression after they were customized!!!! Can one say,"Waste of time and money?"
Any other questions and/or comments?
Be well,
Frank McCune