Doug writes:
I just did the same swap you described on my '72 spit.
I figured out the part numbers for the throttle linkage
bits I needed, but no one here carries them, and I checked
with Rimmer Bros in England, and they couldn't help.
Anyway, I was able to cobble up something that works fine.
You refer to HS4's on the 1300 engines, but I am
sure they used HS2's (which is what I have),
What did you do with the vacuum advance? The MK IV had
a vacuum retard thing whose only purpose is to retard at idle
(for emissions, I guess), and had no effect other than at idle.
Because of this, I simply left it unconnected, and advanced the idle
timing to compensate. Do you have any better idea?
Would it make any sense to mess with the carb needles?
The stock needles were presumably set up for the non-emissions
1300, and I have the stock MK IV emissions
Adam replies:
I have a 1980 spitfire with twin HS2's on a Mk III intake manifold, and had
the same advance problem with the distributor. My solution was to get a
large black phenolic carb insulator (7/8") from the local britcar part place,
rip it in half, sand smooth and drill a hole and expoxy in a vacuum port.
I replaced both stock carb insulators with these and connected the stock
distributor to the new port. Now the ignition is retarded at idle and the
manifold vacuum makes the retard go away at speed. If anyone else has a
better solution, I'd love to hear it, becuase the car is still not yet
runnin as well as I think it might. Also would like to get people's opinions
on re-jetting and re-needling H2S's for the spitfire 1500 motor.
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