Need some D-Jet help. Options

[DerekKim]

Hello. I have a 1973 1.7 D-Jet and am having some issues with my vacuum canister on the distributor. It is a 2 connection distirbutor. First off.

Can anyone explain to me exactly how the 2 connection works?

And number 2-
Can I plug it and use a 1 connection?

The reason why I ask is because PP has to order them(and even then it may be NLA) and it's 24$ for the 1 connection and 188$ for the 2. I can't really afford a 2 connection.


Any help is appreciated.


Thanks,
Derek

[pbanders]

From the Bosch Ignition Tech guide, with my comments:

VACUUM ADVANCE MECHANISM
The lower the load on the engine, the earlier the air/fuel mixture needs to be ignited, since it burns more slowly. The percentage of burned but non-exhausted residual gases in the combustion chamber increases and the mixture becomes leaner.

The vacuum advance port in the throttle body is positioned just above the throttle plate when it is closed. When the throttle is slightly opened (light part-load conditions), intake air passes at high speed directly by the advance port, creating a vacuum (Bernoulli effect) that causes the advance mechanism on the distributor to activate. As the throttle is opened wider, the effect diminishes and the vacuum decreases.

VACUUM RETARD MECHANISM
When the throttle is closed (as in overrun or idle conditions), the ignition point is retarded to produce lower emissions.

The vacuum retard port is positioned in the throttle body just below the throttle plate when it is closed. When the throttle is opened even slightly, vacuum in the port abruptly decreases and the retard mechanism is deactivated.

Note that the vacuum advance mechanism is dominant over the retard mechanism - if you pull a vacuum on both ports, the timing will be advanced, not retarded.

Later cars lacked the vacuum advance port.