Well, my Spitfire ran under its own power around the block a few
times last night. The freeze plug just stopped leaking. I guess that
means the inside of the cooling system has rusted already ;-). It had very
little power and I was quite upset until I read the Bently manual that says
time it at 2 atdc rather than the 10 btdc I had seemed to remember and set.
This brings me to my questions. We have discussed how the timing
advance
was changed over the years to meet pollution standards. I'm considering taking
the springs out of an early distributor I have laying around. This will change
the advance, but then how do I set the timing? From the Bently manual it
appears
the mechanical advance gives about 16 degrees of advance at ~3500 rpm. Should I
put the new springs in and set the timing to 16 atdc @ 3500 rpm?
Also, the vacuum unit is a retard type (I think). What are the
ramifications
of disconnecting this altogether? I'm a little cloudy on its purpose. It
seems it
is designed to retard the timing when there is a high manifold vacuum. Is this
to give more burning time when the mixture is too rich (say when the throttle is
snapped shut at highway speed)? The bently manual does not say whether to time
the
engine with it connected or not. I guess I should add that I'm using an old cd
carb
from a 72 1300 engine rather than the 1979 version originally on the car. The
72 carb
only has a manifold vacuum port. I still have the later Lucas electronic
ignition
on it. Perhaps my vacuum unit is supposed to have 'idle vacuum' only, not
manifold
vacuum as it has at present, and I am causing it to retard the timing at when
its not
supposed to. I have re-read timing.muller from the sol archives and didn't get
enough depth on these topics.
Thanks in advance,
woodruff2caen.engin.umich.edu
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