wrote in message
ups.com...
More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR

The terminology has changed from time to time. DKW (German) made such an
engine, as did Jawa (Czech, I think) and Vostok (Russian). I have seen them
called "undoubled" engines as well as "twin cylinder."

The old Taylor books from MIT called them "U-chamber" engines, or something
like that.

Which manufacturer were you thinking of?

--
Ed Huntress