Interesting story, Bill. My other car ('67 Barracuda) nominally has
10.5:1 compression from the factory, and it does run on 92 octane,
although I had to back off the timing 2 degrees. Undoubtedly the
particular configuration of the combustion chamber has an effect on which
engines can tolerate high compression, and as you point out, the MGB
engine is not outstanding in that regard.
WSpohn4@aol.com had this to say:
><Unless you are planning to use the car for racing only, using racing fuel,
>do not exceed 9 to 1 compression. Your engine is virtually guaranteed to
>ping and run on, causing expensive damage to pistons and bearings, if you
>exceed this figure. 92 Octane just cannot handle that high a compression
>ratio.>
>
>Lawrie, I more or less agree, but I think you are being just a touch
>conservative. I have run engines at 10:1 on pump premium without problem,
>but
>you do have to watch the timing. I agree that 9 would be safer for most
>people.
>
[historic details snipped]
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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