page 73 of the book
"The Internal Combustion Engine"
by CF Taylor and son
has the pair of important graphs
on quench clearance and squish area.
To give you a rough idea
at 2000 rpm
on an engine with a 2.75 inch stroke
and 10 to 1 compression ratio
a piston design with 0% squish area
needed roughly 95 octane fuel
to keep from detonating
and needed
about 29 degrees btdc timing
to make best power
In contrast
the same engine, rpm, CR and conditions
with a piston design giving 50% squish area
only needed 75 octane fuel
and 14 btdc degrees of ignition timing for best power
This was with a 'Very Tight'
0.0065 times bore quench clearance.
That worked out to 0.018 inches on the 2.75 inch diameter bore engine in the test
It would be 0.026 inches on a 4.00 inch bore engine
the actual graphs show the effects using compression ratios from 4 to as much as 16,
and with 0, 10, 20, 30, 40 and 50 percent squish areas
there used to be an article
on the Edelbrock website
by Hugh McCandless about a 360V8 with aluminum Edelbrock cylinder heads
where he points out that he set the quench clearance at 0.026 inches for the 4.00 bore
the old web address for the article was
http://www.edelbrock.com/automotive/stories/hpm907/index.htmlbut unfortunately it seems to have disappeared
and the Google sponsored Wayback machine does not seem to have a cached copy
http://web.archive.org/collections/web.htmlPerhaps someone knows a web link to it?
I think the title was 'Feeling Light Headed'
