What's wrong? Never thought I'd have to ask!

[Joe K]

Joe K, I may be confused, but I believe that a higher compression requires less not more spark advance, as the fuel burns faster as compression increases??? I may be misreading your post.

You may be correct. And I may be mis-remembering the CFR Engine "Octane Test" from college which varied various parameters and given standard parameters could be used to derive the octane number.

Professor gave us "White Gas" (Coleman Fuel) - which as an octane rating is perhaps in the mid-70s.

Stick with Vince.

Joe K