Greeting Scions.
The 64 Spit is running great except for a little problem during
acceleration. Granted, I have not yet attempted to fix it, and I am looking
for ideas before fiddling with all kinds of things. During acceleration
there is a "flat spot" in the acceleration curve starting at about 2800 rpm
up to about 3400 rpm. No missing, no surging, just a definite flat spot.
Typically this occurs under part throttle. Under full throttle it
diminishes somewhat, but the car still doesn't pull quite as strong as it
should in that rev range (although above 3400 it zings pretty good). Since
I know that the mechanical advance mechanism in my Delco distributor is not
functioning, I thought I'd start there first, by removing it, dismantling it
(again - aarrgghh), driving out the pin and fixing the advance. I get
plenty of vacuum advance now at idle and part throttle openings, but no
mechanical advance. Is this the most likely cause?
My other thoughts were (1) I may need different needles for the stock SU
carbs since I have a slightly hotter street cam in it now, plus
ported/polished head, headers and free flow exhaust, and am still using the
stock needles - any ideas on size? (2) Adjust the mixture in the carbs -
(but I don't think that will do it as I already adjusted them and it runs
and idles fine otherwise), (3) Check the coil to ensure proper functioning
(4) ?????????? Frankly, I can't think of anything other than carburation
and ignition that could cause the flat spot so I am open to any and all
other ideas. Thanks.
Ross D. Vincenti
64 Spitfire 4
64 Porsche 356C Coupe
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