It was asked, in regards to compression ratios:
> Since both vehicles have the same bore and stroke, what makes the
> compression ratio lower on the truck?
The size of the combustion chamber. Enlarge the 'open' area in the
head and the CR goes down. That's why shaving a head will raise the
compression ratio: by taking off metal, you've reduced the chamber
area and thus the swept area (bore x stroke) has a smaller area to
be squeezed into.
Also note that the R pistons, with their domes, intrude into the
chamber area, effectively making it smaller (and thus raising CR), By the
same token, the dished H20 pistons make for an effectively larger
chamber and thus lower CR.
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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