Another interesting development. I just changed the spark plugs to NGK BPR6HS (apparently they are the same as the BP6HS, but with a resistor added -- I called NGK), which are the equivalents of the Boschs recommended for the B20B. Anyway, they are about 1/2 inch shorter than the ones the mechanic in Toronto had put in there last fall. All of a sudden, pretty much no ping at all.
Is it possible that the plugs which were in there, being too long (if they were) made the combustion chamber smaller, and so increased the compression, and so made the gas ignite earlier than it normally would with any given timing setting?
Greg
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