Spridgeteers,
I ran a modified 1972 1300cc Ford Escort Sport for a few years in England. I
had a 32/36 Weber carb on it. I took it to a couple of dyno sessions and
adjustments/jet changes were made, but could never quite get rid of the
"stumble". I also advanced the ignition. BTW - The Weber DGV series was
designed for Ford and Renault cars(In DFAV, the F stands for French) with
engines from 1300 to 2000 cc, but I always thought it was better suited to
engines in the 1600 to 2000 cc category.
Check the DGV specs for a Spitfire at:
http://www.teglerizer.com/dcoe/index.html#The
... and for an MGB (with diagram, etc):
http://www.mgbexperience.com/reference/3236dgev.html
This paragraph from the web page above: "This carburetor requires excessive
initial
ignition timing advance to avoid stumble on take off (if the ignition timing
was retarded, we would have to open the primary throttle plate to obtain the
necessary idle; this would expose the progression bleed holes which in turn
would require that the idle mixture be leaned to
compensate for this richer mixture condition. The end result being very
little progressive richening upon further throttle opening, especially at
snap throttle and so the stumble".
JLC in San Diego
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