I think most 16 valve engines are interference as you cantmake the chamber
in a way that all the valves are clear
from the piston. The chamber on 16 valves has to be
symmetrical, while on a 2 valve per cylinder, you could
have the valves on one side of the chamber that you
would make raised, while the other side would be
lower, to keep the compression ratio through the head.
Having said that...
> I believe the 405 DL (low
> compression) is not an interference engine.
The compression ratio is not the issue. Even at 7:1that you can find on some
turbo engines, you'll find
interference engines. Beside, the head is not the only
way to have high compression, you could have a
long stroker that could produce 13:1 and still be
non interference, even at 4 valves/cylinder.
The Fiat/Lancia 2L is a short stroker, and is an
interference engine. I dont have the specs on the DL,
but chances are it is too. There is a site on the web
that has a list of interference engines, but I cant remember
where I saw that...
Ciao,
Francois Dion (francois@hyperreal.org)
-- Member: FLU #1722, PCNA http://www.fortunecity.com/silverstone/zagato/101/launch.html Alfa Romeo, Fiat, Lancia, Peugeot, Volvo, Solex