Dave:
Noticed a couple of more responsi to your
Weber ("to vacuum or not to vacuum?") question as I review the weeks
mail upon
returning home this morning.
For those of you NOT inclined to run "vacuum":
NAPA sells a rebuilt Lucas 23D (strictly mechanical advance) under part
number
48400 (48-400?) which is a copy of the
40819 Cooper "S" curve for those of you
so inclined; remember, this curve was used for "foot on the floor"
driving during
the days of 100+ RON leaded gasolines.
According to the Official Workshop Manual, this dizzy will give about 30
degrees of advance at 6,500 rpm with
a static setting of "0". Now this is the
dizzy's own curve. With a static setting
of 7 degrees as recommended in the
Official Workshop Manual, that works out
to 37 degrees @ 6,500....that's a lot even
even at 8.8-1 stock CR using 93PON unleaded.
It's got a 15 degree "swing" in it so use
caution in terms of total advance when
setting "initial". You might want
to shorten the curve to 12 degrees or so
to give decent advance for reasonable low end torque without going "over
the top" in terms of total advance.
On the stock 1275 (this dizzy was also
used on some stock early 1275 Sprites)
the "book" dynamic ignition setting is
given as 22 degrees BTDC @ 1200rpm
while "static" is given as 7 degrees BTDC.
CAUTION:
Watch these settings as you could end up
with more than the engine can stand on
today's "garbage" octane unleadeds, unless you use a little less initial
"static"
(or "dynamic") advance than recommended during the days of 100+RON
leadeds, or shorten the curve
a few degrees to make the curve more
suitable for today's unleaded premium
pump octanes.
I had a pro make this mistake and burned
holes in pistons at 10,000 miles on a prior
"tuned" 11.0-1 motor, even while running
a (100RON) "mix" of 93PON unleaded and CAM2 racing gas.....so "be
careful out
there"!! :)
Cap'n. Bob
'60 :{)
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