> So compression is based on cylinder volume? More volume, more air to
> compress, bigger explosion...
Compression ratio is the ratio of maximum cylinder volume to minimum
cylinder volume, or as it's usually expressed (S + U)/U where S is the swept
area (bore^2 * stroke * Pi/4) and U is the unswept area, which is mostly the
combustion chamber volume, plus any adjustments for piston pop-up or dish,
head gasket volume, and deck height.
> Then would the head have to be worked on to compensate? Because it could
> be over 10 to 1 compression if it is an HE engine right?
I'll let others comment on the effect of mixing components, as I just don't
know that much about the 6-pot. But according to Piggott, the HE engine was
never more than 9.5:1; and if I run the above formula backwards then
forwards (assuming a 7.47cm bore & 9.5cm stroke, also from Bill), I get that
a .020" overbore will increase it to a whopping 9.6:1. Of course I am using
a Pentium ... so YMMV <g>
Randall
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