Nina:
The 8.7 to 1 pistons are the ones to use. Also, The higher the compression,
the higher the octane requirement. If you do a proper engine rebuild, you
will probably need premium fuel. The factory recommended this when the cars
were new. The 8.to 1 pistons were used in the later V type engines.
Cheers:
Skip.........At 08:16 PM 11/8/97 -0700, Nina Barton wrote:
>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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