Since determining that my GT will need an engine rebuild, I have been
looking at my MG bookmarks in Netscape and picked up the British Automotive
technical info on Pistons and engine rebuilding. The Piston info states
that our cars should have a compression of 9:1 to run properly on today's
unleaded gas. My understanding is that early cars (to 1971) have an 8.7:1
compression ratio and later cars have 8:1. Why would a higher compression
enable me to use a lower octane gas? Does a machine shop determine the
piston dish size to achieve a certain compression ratio? Is there a FAQ or
book available which would explain these things to me? I'm new at this,
and figure that if I'm going to try doing an engine rebuld, I'd like to
understand why things work the way they do.
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