The waterboxer motor was actually developed in 1977 (so my info source says).
It was just coincidental that the C. A. F. E.  gas standards changed in 1984
at the same time VW was introducing the Wasserboxer engine for the Vanagon.

The lowering of octane (lower octane, burns hotter) was bad for the
air-cooled engine since the valve lift was low and duration short, so the at
the slower, hotter burning fuel exhaust was not completely flushed out of the
cylinder when the valve closed, resulting in higher head temperatures.
High-lift ratio rockers and lowering the cylinder compression are a few of
the solutions for the air-cooled engine.

Water-cooled engines run cooler than air-cooled, can tolerate a lower octane
without the overheating.

I went through 3 rebuilt engines in my 64 bus in the nineties trying to use
it as a daily driver.
The bus I owned before 1984 was sold with 80,000 miles on the rebuilt engine.
And I drove it every day in the summer in Phoenix.

 Of the engines that blew in (less demanding weather) only one reached 47,000
miles.(1992). The last engine only made 21,000. The GEX (93)only hit 35,000.
I peeled the "air-cooled rules" sticker off the bumper, and sold it with it's
third engine in 5 years.
I made my escape to a Diesel Westfalia that now runs a 95 Golf lll. It was
the most practical choice for the Diesel Vanagon.
I heard that someone is planning to sell German 112 hp waterboxer engines in
the US. These are stock US cases with German parts. When I find out more I
will let you know.

Robert

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