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<DIV>If you change to a lower octane then it is more likely to ping/pink, and
this is more likely to happen in a high compression engine than a low. If
you must use that fuel - is it cheaper? - just back the timing off until
you can't hear pinking at any combination of throttle opening, revs and
load.</DIV>
<DIV> </DIV>
<DIV>The factory specs on original fuel were conservative to take account of
engine component tolerances and many engines can run more advance without
problems and give better acceleration and cruising economy - BT, DT back in the
day. Haynes agrees and says to run at full throttle between 30 and 50 in
top gear and set the timing so that faint pinking can just be heard. For
me that's too aggressive, like you I've had part-throttle pinking on hills that
goes at full throttle, hence my modified recommendation. I also found that
the change to unleaded increased the tendency to pink, so on this engine that
never could run more advance than book on leaded has to be slightly retarded
from book on unleaded. E5 hasn't made any difference, E10 will be arriving
here this year but only in the lower of the two octanes usually available, so I
will continue to use the higher in the roadster, and change to that in the
'low compression' V8. </DIV>
<DIV> </DIV>
<DIV>PaulH.</DIV>
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<DIV>It appears to run well enough, but I have had a couple of issues come up
where there was a low-speed but high load situation, like going up a short
hill with a 15 mph speed limit. I could hear it pinging some. <BR
data-mce-bogus="1">...</DIV>
<DIV>I expected the timing to be too far advanced at that RPM, but if
anything, it was slightly retarded.</DIV>
<DIV>'''<BR data-mce-bogus="1"></DIV>
<DIV>Does anyone else run 87 in a high compression engine, or have I gone off
on a fool's errand here?</DIV></DIV></BLOCKQUOTE></BODY></HTML>