<< Another engine that doesn't like high compression ratio is the
Jag XK. That deep hemi head requires a pop up pistion to make compression
and the plug is off to one side so 9:1 is it. Thers are lot's of other
variables like quench, squish, and such but the theory is the same.
Regards,
Bill Eastman>>
The real challenge in a hemi engine is to find a high compression crown shape
that doesn't get in the way of a combustion process that is often already
marginal. Any increase in height often gets right in the way of optimal flame
front propogation. You _can_ run high compressions in a Jag engine but must be
very careful how you do it — a potentially expensive learning curve.
I have the same problem in the Twincam, although at around 12:1 it isn't as
bad as the engines that run 13.5:1 (that makes em _really_ sit up and move,
for a while, at least).
Bill S.
|